Research ArticleInfluenceofRedMudProportiononCircularConcrete-FilledSteelTubular Short Columns
Wu Bin 12 Tan Zhuoying1 Li Fan3 and Wang Sun4
1School of Civil and Resource Engineering University of Science and Technology Beijing Beijing 100083 China2Department of Construction Engineering Liaoning Provincial College of Communications Shenyang Liaoning 110122 China3Hannoer Greenland Venue Management Co Ltd Shanghai 100083 China4Architectural and Civil Engineering College Shenyang University Shenyang Liaoning 110044 China
Correspondence should be addressed to Wu Bin 66084537qqcom
Received 30 March 2020 Revised 22 June 2020 Accepted 30 July 2020 Published 24 August 2020
Guest Editor Norbert Randl
Copyright copy 2020Wu Bin et alis is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
Tests on twelve circular concrete-filled steel tube stub columns with mixed red mud and three circular concrete-filled steel tubestub columns to investigate the influence of the mixed proportion of red mud on the mechanical behavior of axial compressivecircular concrete-filled steel tube stub columns are reported It is found that with the increase of red mud content the ultimateload increases first and then decreases on the contrary the ultimate displacement decreases first and then increases the specimenstress reaches the proportion limitation as the steel tube longitudinal strain is around 160 με and reaches the yield limitation as thesteel tubesrsquo longitudinal strain is around 4400sim5000 με e axial compressive bearing capacity empirical formulation of concrete-filled steel tubes stub columns mixed with red mud is proposed e theoretical calculation results agree well with thoseexperimental data
1 Introduction
Circular concrete-filled steel tube (CCFST) can provideexcellent structural properties such as high bearing capacityand high ductility and the steel tube of CCFSTcan be used aspermanent formwork to reduce the construction schedulewithout any effect by seasonal climate erefore a con-siderable amount of studies on CCFST have been carried outin recent decades [1ndash9] which make this kind of structuremore and more widely used in subways tunnels bridgeshigh-rise and super high-rise buildings
Various studies of the utilization of solid waste in theconstruction industry have been conducted in recent years[10ndash13] Most of the solid wastes generally produce certainradiation and corrosiveness and the poured concrete withmixing those solid wastes normally engenders attribute ofhigh dispersion However the steel tube has the charac-teristics of radiation protection and corrosion resistanceand it has a behavior to constrain the dispersion of concreteerefore the solid wastes utilized in the CCFST would
greatly improve the utilization rate of solid wastes in theworld Nowadays the research works of solid wastes inCCFST [14ndash16] have already been conducted and achievedsome research results
As a result this paper takes red mud as a research objectto study its effective utilization Red mud as a solid wasteproduced in the process of bauxite extraction occupies alarge amount of land Its high alkali content causes seriouspollution in the surroundings which makes the red muddisposal and utilization increasingly prominent [17] Atpresent the main field of red mud treatment is in theconstruction industry and some achievements have beenmade It was found that red mud had good cementationsrsquoactivity and could be well utilized [18] Liu and Poon [19]used bauxite residue-red mud instead of part of fly ash tomake self-compacting concrete in order to test its me-chanical behavior It was found that the compressivestrength the splitting tensile strength and the elasticmodulus of the specimens were increased respectively Wuet al [20] put forward the concept of the CCFSTmixed with
HindawiAdvances in Materials Science and EngineeringVolume 2020 Article ID 8578059 11 pageshttpsdoiorg10115520208578059
red mud first and conducted experimental research onpushing core concrete out of steel tube e research resultindicated that the bond slip behavior of the CCFST mixedwith red mud was improved it was proved that the cementof core concrete could be partly replaced by the red mud
In order to investigate the influence of mixing pro-portion of the red mud on the mechanical behaviors ofCCFSTstub columns under axial compressive load the testson a total of fifteen specimens under axial compressivebearing load including twelve specimens of CCFST stubcolumns mixing with the red mud and three specimens ofCCFST stub columns are reported in this paper e mainobjective of these tests was twofold firstly to derive theempirical formulation of axial compressive bearing capacityby the discussion on the influence of mixing proportion ofthe red mud in CCFSTstub columns and secondly to verifythe correctness of the formulation by comparing and ana-lyzing the calculation results and the test data
2 Experimental Study
21 Specimen Material
(1) Steel tube a seamless circular steel tube was appliedAccording to Chinese Code GBT228-2002 thetensile test method of metal material at the status ofroom temperature the yield strength fy tensilestrength fu elastic modulus Es yield strain εsy andPoissonrsquos ratio ]s will be determined shown inTable 1
(2) Concrete Yatai brand 425R normal cement mixedwith 5sim15mm aggregates the river sand and the tapwater the superplasticize was applied from LiaoningJianfeng Industrial Co Ltd Bauxite residue-redmud generated in Beihai Alumina Plant WeiqiaoShandong Province e chemical composition ofthe red mud is shown in Table 2 e quality sub-stitution rate of the red mud in the concrete wasapplied for 0 5 10 15 and 20 respectivelye mixture ratio of the red mud concrete was inaccordance with the Chinese standard JGJ55-2001mix design of normal concrete as can be seen inTable 3
22 Specimen Labels and Parameters A total of fifteenspecimens were constructed including twelve CCFST stubcolumns mixed with the red mud and three CCFST stubcolumns A summary of the specimen information is givenin Table 4 e specimens labeled as CSC are for CircularStub Column the fourth letter labeled as A B or C is for theexternal diameter of the specimens of 108mm 133mm or159mm and the last Arabic numeral labeled 1 2 3 4 or 5 isfor the quality substitution rate of the red mud of 0 510 15 or 20 L is the length of the stub columnD is theexternal diameter of the circular steel tube ts stands for thewall thickness of the steel tube r means the quality sub-stitution rate of the red mud fcu means the cubic com-pressive strength of concreteα means the steel content ξs
stands for the confining factor Neu is the ultimate bearing
capacity of stub column
23 Specimens Fabrication A circular steel tube was cut intofifteen steel tubes according to the length shown in Table 4on the automatic cutting machine All the specimens werethree times the diameter in length to reduce the end effectsand to ensure that the specimens would be stub columnswith minimum effect from slenderness Each tube waswelded to a 200mmtimes 200mmtimes 10mm steel base plate at thebottom of the steel tube Fifteen same size steel plates weremilled with a 3mm deep concentric round groove whichdiameter was 02mm bigger than the external diameter ofthe steel tubes and was used as the movable cover plates onthe top of the steel tubes e red mud concrete was pouredfrom the top of the steel tube and compacted with vibrationuntil the redmud concrete was higher than the top surface ofthe steel tube All the specimens were cured for 2weeks thenthe top surface of the red mud concrete-filled steel tube wasground smooth and flushed with the steel tube by using anangle polishingmachinee steel cover plate covered on thetop surface of the steel tubeis was done to ensure that theload was applied evenly across the cross-section and si-multaneously to the steel tube and concrete core See Fig-ures 1 and 2 for the fabricated test specimens
24 Test Arrangement andMeasurement e loading deviceand measuring equipment are shown in Figures 3 and 4 Allthe specimens were tested with a universal testing machinewith a 2000 kN capacity in the structural engineering lab-oratory of Liaoning Construction Sciences Academy elongitudinal displacement of each specimen was measuredby two transducers with ameasurement range of 50mmearrangement of strain gauges is shown in Figure 5 erewere 8 strain gauges in total including 4 longitudinal straingauges and 4 circumferential strain gauges (points 1ndash4) etype of strain gauge was BX120-5AA and the size was 50times 3TDS602 was used for collecting relative strain anddisplacement
25 Loading System According to Chinese Code GBT50152-2012 Standard for test method of concrete structuresthe test adopted method of load increment as shown inFigure 6 e estimated ultimate loads of the 3 series A B Cspecimens were about 900 kN 1300 kN and 1700 kN re-spectively e preloading value was applied 10 of theestimated ultimate load in order to make a concentric ad-justment imposing on specimens en the loads wereapplied in increments of 110 of the estimated ultimate load
in the elastic range When the target loads were reachedeach target load was maintained for 2mins on the specimenAs the load reached 60 of the estimated ultimate load(540 kN 780 kN and 1020 kN respectively) the loads were
applied in an increment of 120 of the estimated ultimateload When the target loads were reached each target loadwas maintained for 2mins as well As the specimen wasunder destruction the load continued to increase slowlyAfter reaching the ultimate load value the loads were ap-plied continuously until the deformation of the specimenwas too big then the test stopped Each test took approx-imately one hour to complete In the whole process of thetest the load readings and deformation measurements wererecorded automatically by the pressure servo machinewhich provided enough data points to complete the drawingof load displacement curve
3 Experimental Results and Discussion
31 Analysis of Experimental Phenomena At the beginningthe specimens were loaded in the elastic stage without ob-vious change When the load reached 60 sim 70 of theultimate load the shear slip line appeared on the steel tubewall As the load reached 80 sim 90 of the ultimate load therust on the steel tube wall started falling down the localbuckling of the steel tube happened and the cross shear slipline emerged en the specimens were in the failure stageBecause the confining factor was relatively big the
Table 2 Red mud chemical composition
Al2O3 Na2Ok Fe2O3 SiO2 TiO2 CaO CO2 H2O H2O Loss PH Density (gcmminus3) 2373 739 2879 2463 222 269 097 859 1 1494 113 32
Table 3 e proportion of red mud concrete Kgm3
SN Red mud Cement Sand Aggregate I Aggregate II Water SuperplasticizeRMC-0 0 360 780 216 862 162 36RMC-5 18 342 780 216 862 162 39RMC-10 36 324 780 216 862 162 42RMC-15 54 306 780 216 862 162 45RMC-20 72 288 780 216 862 162 48Note RMC labeled for red mud concrete 0 5 10 15 and 20 are for quality substitution rate of red mud 0 5 10 15 and 20 respectively
Table 4 Parameters of the specimens
SN Specimen L (mm) D (mm) ts (mm) r () fy (MPa) fcu (MPa) D (ts) α ξs Neu (kN)
drum-shaped failure occurred (Figure 7) while the speci-mens showed good ductility After the ultimate load wasreached the bearing capacity of the specimens was differentaccording to the different confining factor For the speci-mens with big confining factor the bearing capacity wasslightly increased For the specimens with small confiningfactor the bearing capacity was slightly decreased For thespecimen with a moderate confining factor the bearingcapacity kept the same e deformation of the specimens inthose 3 situations was continuously increasing until thespecimens were loaded to failure e failure modality of the
CCFSTwith the red mud specimen was similar to the failuremodality of the CCFST specimen Figure 8 shows all thespecimens with failure mode
32 Influence of Mixed Red Mud e load (kN) versusdisplacement (mm) curves for the 3 groups specimens (A BC) are presented in Figure 9
As shown in Figure 9 the load (kN) versus axial dis-placement (mm) curves for the 3 series of specimens are littledifferent It was found that with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stubcolumn the ultimate load of specimens increased first andthen decreased e ultimate load was the maximum asr 5 the ultimate load on the CCFST with the red mudspecimens for groups A B and C were 10034 kN14036 kN and 18845 kN respectively which increased1330 884 and 1561 compared with those 3 CCFSTspecimens As r 20 the ultimate load on the CCFSTwiththe red mud specimens for groups A B and C were8605 kN 12656 kN and 1600 kN respectively which de-creased 283 186 and 185 than the ultimate load onthe 3 CCFST specimens It illustrates that when the qualitysubstitution rate of the red mud is between 0sim20 theultimate load on the CCFSTwith the red mud increases thereasons of which are twofold firstly the red mud has thecharacteristics of pozzolanic During the hydration ofconcrete Ca (OH)2 was produced It reacted with activeSiO2 Fe2O3 and Al2O3 produced from the red mud in thesecond time hydration and generated the hydrate calcium
Pressure plate
Top plate (movable)
Bottom plate
Pressure plate
Transducers
SpecimenStrain gauges
N
N
Figure 4 Column test layout
1
24
3
Figure 5 Arrangement of the strain gauges measuring equipment
200
1010
Top plate (movable)
Top plate (movable)Specimen
Specimen
Specimen
Fillet weld
Bottom plate
200
200
200
10
3
D
D + 02
Top plate (movable)
Fillet weld
Bottom plate
200
200
ts
ts
L DD + 02
Figure 2 e specimens geometry
Figure 3 e loading device
4 Advances in Materials Science and Engineering
silicate and the hydrate calcium acuminate In the process ofthe reaction Ca (OH)2 generated was being consumedwhich caused further hydration reaction promoted estructure of the interface between the internal medium ofconcrete was improved e compressive strength of con-crete was enhanced and secondly the red mud particleswere finer after processing its specific surface area wasbigger than 400m2kg while the specific surface area of
Portland cement was only bigger than 300m2kg ereforethe red mud played a physical filling role in the concreteeconcrete mixing with the red mud would have smaller poresand lower porosity which caused the compactness of theconcrete was raised As a result the compressive strength ofthe concrete would be improved
As seen in Figure 9 with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stub
Note(1) e horizontal line is to keep the load unchanged for two minutes(2) Oblique straight line is the load that increases slowly
Figure 6 Simplified diagram of the method of load increment
Advances in Materials Science and Engineering 5
column the ultimate displacement of the specimens de-creased first and then increased the ultimate displacementwas minimum as r 5 the ultimate displacement of theCCFST with the red mud specimens for groups A B and Cwere 58mm 45mm and 33mm respectively decreased1077 1964 and 2667 than those 3 CCFSTspecimensAs r 20 the ultimate displacement of the CCFSTwith thered mud specimens for groups A B and C was 66mm59mm and 47mm respectively increased 154 536and 444 than the ultimate displacement of the 3 CCFSTspecimens Obviously when the quality substitution rate ofthe red mud was between 0sim20 the ultimate displace-ment of the CCFST with the red mud specimens decreasedand the ductility became weaker compared with the CCFSTspecimens the main reason of which was that the strength of
the CCFST mixing the red mud was improved and thestiffness was enhanced
33 Analysis of the Whole Process of Stress Strain enominal compressive stress of the specimen is σsc NAsc
σsc is the nominal compressive stress of the specimenN is the axial pressureAsc is the cross-sectional area of the specimen
e axial compressive strain of the specimen is εsl ΔL
εsl is the compressive strain of the specimenΔ is the axial deformationL is the height of the specimen
0
500
1000
1500N
(KN
)
0 5 10 15 20 25Δ (mm)
CSCA-1CSCA-2CSCA-3
CSCA-4CSCA-5
(a)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCB-4CSCB-5
CSCB-1CSCB-2CSCB-3
(b)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCC-1CSCC-2CSCC-3
CSCC-4CSCC-5
(c)
Figure 9 e load versus displacement curves (a) Group A (b) Group B (c) Group C
6 Advances in Materials Science and Engineering
According to Figure 8 the typical σsc minus εsl curves of thespecimens were obtained as shown in Figure 10
As can be seen from Figure 10 the curve mainly un-dergoes three stages elastic stage (OA) elastic-plastic stage(AB) and ascendingdescendinghorizontal stage (BC)
OA stage the curve is linear It indicates that the qualitysubstitution rate of the red mud has little effect on thestiffness when the specimen is in the elastic stage e steeltube and the red mud concrete have not been working welltogether When reaching point A the steel tube is in acompressive yield state the longitudinal strain is about1600 με the circumferential strain is around 450 με and thespecimen reaches the proportional limitation
AB stage the specimen is in the elastic-plastic stage andthe steel tube and the red mud concrete bear the load si-multaneously With the development of the red mud con-crete cracks in the steel tube the transverse deformationexceeds the Poissonrsquos ratio of the steel tube Mutual ex-trusion produced between these two materials causes thesteel tube to produce the confinement effect on the red mudconcrete core At the same time the redmud concrete core isin a three-dimensional compressive state erefore thebearing capacity of the specimen is enhanced As reachingpoint B the longitudinal strain of the steel tube is about4400sim5000 με and the specimen reaches the yield limitation
BC stage when it exceeds point B the curve is dividedinto three situations according to the different confiningfactor As ξs ξ0 the curve is basically horizontal as ξs gt ξ0it becomes a slowly rising curve the bigger the confiningfactor is the larger the rise range is and vice versa as ξs lt ξ0it is a gradually falling curve the smaller the confining factoris the larger the decline range is and vice versa Accordingto Table 4 and Figure 9 ξ0 11
4 Simplified Calculation of Axial CompressiveBearing Capacity
419eProposedEmpirical Formulation ofAxialCompressiveBearing Capacity of Stub Column According to Figure 9when the specimens reach the peak load the deformation is
too big e components would have lost their usagefunction if they were applied in the real projects ereforethe ultimate yield strength fscy of the specimen (longitu-dinal strain is about 4400ndash5000 με) determined by the stress-strain relations shown in Figure 10 is defined as the ultimatestrength of the axial compressive bearing capacity of thespecimen In the range of quality substitution rate of the redmud r 0sim20 regression analysis of test data is carriedout as shown in Figures 11 and 12
e formulation of fscy proposed by regression analysisis as follows
fscy φr 2094 + 0765ξs( 1113857fck (1)
en the axial compressive bearing capacity formula-tion of the CCFSTstub columnwith the redmud is proposedas follows
Nu fscyAsc (2)
φr 0993 minus 1480r + 8261r2 (3)
Asc As + Ac (4)
fscy is the ultimate strength of axial compressive bearingcapacity fckis the standard value of compressive strength ofconcrete fck 067fcu ξs is the confining factor of steeltube ξs (fyAsfckAc) Nuis the axial compressive bearingcapacity of stub column Ascis the composite section area ofCCFST stub column with red mud As is the section area ofsteel tube of CCFST stub column with red mud Ac is thesection area of concrete of CCFST stub column with redmud φr is the influence coefficient of quality substitutionrate of the red mud r is the quality substitution rate of thered mud
When r 0 it can be seen as the formulation of theaxial compressive bearing capacity of the CCFST stubcolumn
C
C
CB
Aξs lt ξ0
ξs gt ξ0
ξs = ξ0
εsl
σ sc
O
Figure 10 e σsc minus εsl relations of the specimens2
3
4
5
1 2 3
f scyf
ck
ξs
fscy = (2094 + 0765ξs)fck
Figure 11 e relationship between ultimate yield strength andconfining factor
Advances in Materials Science and Engineering 7
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
red mud first and conducted experimental research onpushing core concrete out of steel tube e research resultindicated that the bond slip behavior of the CCFST mixedwith red mud was improved it was proved that the cementof core concrete could be partly replaced by the red mud
In order to investigate the influence of mixing pro-portion of the red mud on the mechanical behaviors ofCCFSTstub columns under axial compressive load the testson a total of fifteen specimens under axial compressivebearing load including twelve specimens of CCFST stubcolumns mixing with the red mud and three specimens ofCCFST stub columns are reported in this paper e mainobjective of these tests was twofold firstly to derive theempirical formulation of axial compressive bearing capacityby the discussion on the influence of mixing proportion ofthe red mud in CCFSTstub columns and secondly to verifythe correctness of the formulation by comparing and ana-lyzing the calculation results and the test data
2 Experimental Study
21 Specimen Material
(1) Steel tube a seamless circular steel tube was appliedAccording to Chinese Code GBT228-2002 thetensile test method of metal material at the status ofroom temperature the yield strength fy tensilestrength fu elastic modulus Es yield strain εsy andPoissonrsquos ratio ]s will be determined shown inTable 1
(2) Concrete Yatai brand 425R normal cement mixedwith 5sim15mm aggregates the river sand and the tapwater the superplasticize was applied from LiaoningJianfeng Industrial Co Ltd Bauxite residue-redmud generated in Beihai Alumina Plant WeiqiaoShandong Province e chemical composition ofthe red mud is shown in Table 2 e quality sub-stitution rate of the red mud in the concrete wasapplied for 0 5 10 15 and 20 respectivelye mixture ratio of the red mud concrete was inaccordance with the Chinese standard JGJ55-2001mix design of normal concrete as can be seen inTable 3
22 Specimen Labels and Parameters A total of fifteenspecimens were constructed including twelve CCFST stubcolumns mixed with the red mud and three CCFST stubcolumns A summary of the specimen information is givenin Table 4 e specimens labeled as CSC are for CircularStub Column the fourth letter labeled as A B or C is for theexternal diameter of the specimens of 108mm 133mm or159mm and the last Arabic numeral labeled 1 2 3 4 or 5 isfor the quality substitution rate of the red mud of 0 510 15 or 20 L is the length of the stub columnD is theexternal diameter of the circular steel tube ts stands for thewall thickness of the steel tube r means the quality sub-stitution rate of the red mud fcu means the cubic com-pressive strength of concreteα means the steel content ξs
stands for the confining factor Neu is the ultimate bearing
capacity of stub column
23 Specimens Fabrication A circular steel tube was cut intofifteen steel tubes according to the length shown in Table 4on the automatic cutting machine All the specimens werethree times the diameter in length to reduce the end effectsand to ensure that the specimens would be stub columnswith minimum effect from slenderness Each tube waswelded to a 200mmtimes 200mmtimes 10mm steel base plate at thebottom of the steel tube Fifteen same size steel plates weremilled with a 3mm deep concentric round groove whichdiameter was 02mm bigger than the external diameter ofthe steel tubes and was used as the movable cover plates onthe top of the steel tubes e red mud concrete was pouredfrom the top of the steel tube and compacted with vibrationuntil the redmud concrete was higher than the top surface ofthe steel tube All the specimens were cured for 2weeks thenthe top surface of the red mud concrete-filled steel tube wasground smooth and flushed with the steel tube by using anangle polishingmachinee steel cover plate covered on thetop surface of the steel tubeis was done to ensure that theload was applied evenly across the cross-section and si-multaneously to the steel tube and concrete core See Fig-ures 1 and 2 for the fabricated test specimens
24 Test Arrangement andMeasurement e loading deviceand measuring equipment are shown in Figures 3 and 4 Allthe specimens were tested with a universal testing machinewith a 2000 kN capacity in the structural engineering lab-oratory of Liaoning Construction Sciences Academy elongitudinal displacement of each specimen was measuredby two transducers with ameasurement range of 50mmearrangement of strain gauges is shown in Figure 5 erewere 8 strain gauges in total including 4 longitudinal straingauges and 4 circumferential strain gauges (points 1ndash4) etype of strain gauge was BX120-5AA and the size was 50times 3TDS602 was used for collecting relative strain anddisplacement
25 Loading System According to Chinese Code GBT50152-2012 Standard for test method of concrete structuresthe test adopted method of load increment as shown inFigure 6 e estimated ultimate loads of the 3 series A B Cspecimens were about 900 kN 1300 kN and 1700 kN re-spectively e preloading value was applied 10 of theestimated ultimate load in order to make a concentric ad-justment imposing on specimens en the loads wereapplied in increments of 110 of the estimated ultimate load
in the elastic range When the target loads were reachedeach target load was maintained for 2mins on the specimenAs the load reached 60 of the estimated ultimate load(540 kN 780 kN and 1020 kN respectively) the loads were
applied in an increment of 120 of the estimated ultimateload When the target loads were reached each target loadwas maintained for 2mins as well As the specimen wasunder destruction the load continued to increase slowlyAfter reaching the ultimate load value the loads were ap-plied continuously until the deformation of the specimenwas too big then the test stopped Each test took approx-imately one hour to complete In the whole process of thetest the load readings and deformation measurements wererecorded automatically by the pressure servo machinewhich provided enough data points to complete the drawingof load displacement curve
3 Experimental Results and Discussion
31 Analysis of Experimental Phenomena At the beginningthe specimens were loaded in the elastic stage without ob-vious change When the load reached 60 sim 70 of theultimate load the shear slip line appeared on the steel tubewall As the load reached 80 sim 90 of the ultimate load therust on the steel tube wall started falling down the localbuckling of the steel tube happened and the cross shear slipline emerged en the specimens were in the failure stageBecause the confining factor was relatively big the
Table 2 Red mud chemical composition
Al2O3 Na2Ok Fe2O3 SiO2 TiO2 CaO CO2 H2O H2O Loss PH Density (gcmminus3) 2373 739 2879 2463 222 269 097 859 1 1494 113 32
Table 3 e proportion of red mud concrete Kgm3
SN Red mud Cement Sand Aggregate I Aggregate II Water SuperplasticizeRMC-0 0 360 780 216 862 162 36RMC-5 18 342 780 216 862 162 39RMC-10 36 324 780 216 862 162 42RMC-15 54 306 780 216 862 162 45RMC-20 72 288 780 216 862 162 48Note RMC labeled for red mud concrete 0 5 10 15 and 20 are for quality substitution rate of red mud 0 5 10 15 and 20 respectively
Table 4 Parameters of the specimens
SN Specimen L (mm) D (mm) ts (mm) r () fy (MPa) fcu (MPa) D (ts) α ξs Neu (kN)
drum-shaped failure occurred (Figure 7) while the speci-mens showed good ductility After the ultimate load wasreached the bearing capacity of the specimens was differentaccording to the different confining factor For the speci-mens with big confining factor the bearing capacity wasslightly increased For the specimens with small confiningfactor the bearing capacity was slightly decreased For thespecimen with a moderate confining factor the bearingcapacity kept the same e deformation of the specimens inthose 3 situations was continuously increasing until thespecimens were loaded to failure e failure modality of the
CCFSTwith the red mud specimen was similar to the failuremodality of the CCFST specimen Figure 8 shows all thespecimens with failure mode
32 Influence of Mixed Red Mud e load (kN) versusdisplacement (mm) curves for the 3 groups specimens (A BC) are presented in Figure 9
As shown in Figure 9 the load (kN) versus axial dis-placement (mm) curves for the 3 series of specimens are littledifferent It was found that with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stubcolumn the ultimate load of specimens increased first andthen decreased e ultimate load was the maximum asr 5 the ultimate load on the CCFST with the red mudspecimens for groups A B and C were 10034 kN14036 kN and 18845 kN respectively which increased1330 884 and 1561 compared with those 3 CCFSTspecimens As r 20 the ultimate load on the CCFSTwiththe red mud specimens for groups A B and C were8605 kN 12656 kN and 1600 kN respectively which de-creased 283 186 and 185 than the ultimate load onthe 3 CCFST specimens It illustrates that when the qualitysubstitution rate of the red mud is between 0sim20 theultimate load on the CCFSTwith the red mud increases thereasons of which are twofold firstly the red mud has thecharacteristics of pozzolanic During the hydration ofconcrete Ca (OH)2 was produced It reacted with activeSiO2 Fe2O3 and Al2O3 produced from the red mud in thesecond time hydration and generated the hydrate calcium
Pressure plate
Top plate (movable)
Bottom plate
Pressure plate
Transducers
SpecimenStrain gauges
N
N
Figure 4 Column test layout
1
24
3
Figure 5 Arrangement of the strain gauges measuring equipment
200
1010
Top plate (movable)
Top plate (movable)Specimen
Specimen
Specimen
Fillet weld
Bottom plate
200
200
200
10
3
D
D + 02
Top plate (movable)
Fillet weld
Bottom plate
200
200
ts
ts
L DD + 02
Figure 2 e specimens geometry
Figure 3 e loading device
4 Advances in Materials Science and Engineering
silicate and the hydrate calcium acuminate In the process ofthe reaction Ca (OH)2 generated was being consumedwhich caused further hydration reaction promoted estructure of the interface between the internal medium ofconcrete was improved e compressive strength of con-crete was enhanced and secondly the red mud particleswere finer after processing its specific surface area wasbigger than 400m2kg while the specific surface area of
Portland cement was only bigger than 300m2kg ereforethe red mud played a physical filling role in the concreteeconcrete mixing with the red mud would have smaller poresand lower porosity which caused the compactness of theconcrete was raised As a result the compressive strength ofthe concrete would be improved
As seen in Figure 9 with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stub
Note(1) e horizontal line is to keep the load unchanged for two minutes(2) Oblique straight line is the load that increases slowly
Figure 6 Simplified diagram of the method of load increment
Advances in Materials Science and Engineering 5
column the ultimate displacement of the specimens de-creased first and then increased the ultimate displacementwas minimum as r 5 the ultimate displacement of theCCFST with the red mud specimens for groups A B and Cwere 58mm 45mm and 33mm respectively decreased1077 1964 and 2667 than those 3 CCFSTspecimensAs r 20 the ultimate displacement of the CCFSTwith thered mud specimens for groups A B and C was 66mm59mm and 47mm respectively increased 154 536and 444 than the ultimate displacement of the 3 CCFSTspecimens Obviously when the quality substitution rate ofthe red mud was between 0sim20 the ultimate displace-ment of the CCFST with the red mud specimens decreasedand the ductility became weaker compared with the CCFSTspecimens the main reason of which was that the strength of
the CCFST mixing the red mud was improved and thestiffness was enhanced
33 Analysis of the Whole Process of Stress Strain enominal compressive stress of the specimen is σsc NAsc
σsc is the nominal compressive stress of the specimenN is the axial pressureAsc is the cross-sectional area of the specimen
e axial compressive strain of the specimen is εsl ΔL
εsl is the compressive strain of the specimenΔ is the axial deformationL is the height of the specimen
0
500
1000
1500N
(KN
)
0 5 10 15 20 25Δ (mm)
CSCA-1CSCA-2CSCA-3
CSCA-4CSCA-5
(a)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCB-4CSCB-5
CSCB-1CSCB-2CSCB-3
(b)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCC-1CSCC-2CSCC-3
CSCC-4CSCC-5
(c)
Figure 9 e load versus displacement curves (a) Group A (b) Group B (c) Group C
6 Advances in Materials Science and Engineering
According to Figure 8 the typical σsc minus εsl curves of thespecimens were obtained as shown in Figure 10
As can be seen from Figure 10 the curve mainly un-dergoes three stages elastic stage (OA) elastic-plastic stage(AB) and ascendingdescendinghorizontal stage (BC)
OA stage the curve is linear It indicates that the qualitysubstitution rate of the red mud has little effect on thestiffness when the specimen is in the elastic stage e steeltube and the red mud concrete have not been working welltogether When reaching point A the steel tube is in acompressive yield state the longitudinal strain is about1600 με the circumferential strain is around 450 με and thespecimen reaches the proportional limitation
AB stage the specimen is in the elastic-plastic stage andthe steel tube and the red mud concrete bear the load si-multaneously With the development of the red mud con-crete cracks in the steel tube the transverse deformationexceeds the Poissonrsquos ratio of the steel tube Mutual ex-trusion produced between these two materials causes thesteel tube to produce the confinement effect on the red mudconcrete core At the same time the redmud concrete core isin a three-dimensional compressive state erefore thebearing capacity of the specimen is enhanced As reachingpoint B the longitudinal strain of the steel tube is about4400sim5000 με and the specimen reaches the yield limitation
BC stage when it exceeds point B the curve is dividedinto three situations according to the different confiningfactor As ξs ξ0 the curve is basically horizontal as ξs gt ξ0it becomes a slowly rising curve the bigger the confiningfactor is the larger the rise range is and vice versa as ξs lt ξ0it is a gradually falling curve the smaller the confining factoris the larger the decline range is and vice versa Accordingto Table 4 and Figure 9 ξ0 11
4 Simplified Calculation of Axial CompressiveBearing Capacity
419eProposedEmpirical Formulation ofAxialCompressiveBearing Capacity of Stub Column According to Figure 9when the specimens reach the peak load the deformation is
too big e components would have lost their usagefunction if they were applied in the real projects ereforethe ultimate yield strength fscy of the specimen (longitu-dinal strain is about 4400ndash5000 με) determined by the stress-strain relations shown in Figure 10 is defined as the ultimatestrength of the axial compressive bearing capacity of thespecimen In the range of quality substitution rate of the redmud r 0sim20 regression analysis of test data is carriedout as shown in Figures 11 and 12
e formulation of fscy proposed by regression analysisis as follows
fscy φr 2094 + 0765ξs( 1113857fck (1)
en the axial compressive bearing capacity formula-tion of the CCFSTstub columnwith the redmud is proposedas follows
Nu fscyAsc (2)
φr 0993 minus 1480r + 8261r2 (3)
Asc As + Ac (4)
fscy is the ultimate strength of axial compressive bearingcapacity fckis the standard value of compressive strength ofconcrete fck 067fcu ξs is the confining factor of steeltube ξs (fyAsfckAc) Nuis the axial compressive bearingcapacity of stub column Ascis the composite section area ofCCFST stub column with red mud As is the section area ofsteel tube of CCFST stub column with red mud Ac is thesection area of concrete of CCFST stub column with redmud φr is the influence coefficient of quality substitutionrate of the red mud r is the quality substitution rate of thered mud
When r 0 it can be seen as the formulation of theaxial compressive bearing capacity of the CCFST stubcolumn
C
C
CB
Aξs lt ξ0
ξs gt ξ0
ξs = ξ0
εsl
σ sc
O
Figure 10 e σsc minus εsl relations of the specimens2
3
4
5
1 2 3
f scyf
ck
ξs
fscy = (2094 + 0765ξs)fck
Figure 11 e relationship between ultimate yield strength andconfining factor
Advances in Materials Science and Engineering 7
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
in the elastic range When the target loads were reachedeach target load was maintained for 2mins on the specimenAs the load reached 60 of the estimated ultimate load(540 kN 780 kN and 1020 kN respectively) the loads were
applied in an increment of 120 of the estimated ultimateload When the target loads were reached each target loadwas maintained for 2mins as well As the specimen wasunder destruction the load continued to increase slowlyAfter reaching the ultimate load value the loads were ap-plied continuously until the deformation of the specimenwas too big then the test stopped Each test took approx-imately one hour to complete In the whole process of thetest the load readings and deformation measurements wererecorded automatically by the pressure servo machinewhich provided enough data points to complete the drawingof load displacement curve
3 Experimental Results and Discussion
31 Analysis of Experimental Phenomena At the beginningthe specimens were loaded in the elastic stage without ob-vious change When the load reached 60 sim 70 of theultimate load the shear slip line appeared on the steel tubewall As the load reached 80 sim 90 of the ultimate load therust on the steel tube wall started falling down the localbuckling of the steel tube happened and the cross shear slipline emerged en the specimens were in the failure stageBecause the confining factor was relatively big the
Table 2 Red mud chemical composition
Al2O3 Na2Ok Fe2O3 SiO2 TiO2 CaO CO2 H2O H2O Loss PH Density (gcmminus3) 2373 739 2879 2463 222 269 097 859 1 1494 113 32
Table 3 e proportion of red mud concrete Kgm3
SN Red mud Cement Sand Aggregate I Aggregate II Water SuperplasticizeRMC-0 0 360 780 216 862 162 36RMC-5 18 342 780 216 862 162 39RMC-10 36 324 780 216 862 162 42RMC-15 54 306 780 216 862 162 45RMC-20 72 288 780 216 862 162 48Note RMC labeled for red mud concrete 0 5 10 15 and 20 are for quality substitution rate of red mud 0 5 10 15 and 20 respectively
Table 4 Parameters of the specimens
SN Specimen L (mm) D (mm) ts (mm) r () fy (MPa) fcu (MPa) D (ts) α ξs Neu (kN)
drum-shaped failure occurred (Figure 7) while the speci-mens showed good ductility After the ultimate load wasreached the bearing capacity of the specimens was differentaccording to the different confining factor For the speci-mens with big confining factor the bearing capacity wasslightly increased For the specimens with small confiningfactor the bearing capacity was slightly decreased For thespecimen with a moderate confining factor the bearingcapacity kept the same e deformation of the specimens inthose 3 situations was continuously increasing until thespecimens were loaded to failure e failure modality of the
CCFSTwith the red mud specimen was similar to the failuremodality of the CCFST specimen Figure 8 shows all thespecimens with failure mode
32 Influence of Mixed Red Mud e load (kN) versusdisplacement (mm) curves for the 3 groups specimens (A BC) are presented in Figure 9
As shown in Figure 9 the load (kN) versus axial dis-placement (mm) curves for the 3 series of specimens are littledifferent It was found that with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stubcolumn the ultimate load of specimens increased first andthen decreased e ultimate load was the maximum asr 5 the ultimate load on the CCFST with the red mudspecimens for groups A B and C were 10034 kN14036 kN and 18845 kN respectively which increased1330 884 and 1561 compared with those 3 CCFSTspecimens As r 20 the ultimate load on the CCFSTwiththe red mud specimens for groups A B and C were8605 kN 12656 kN and 1600 kN respectively which de-creased 283 186 and 185 than the ultimate load onthe 3 CCFST specimens It illustrates that when the qualitysubstitution rate of the red mud is between 0sim20 theultimate load on the CCFSTwith the red mud increases thereasons of which are twofold firstly the red mud has thecharacteristics of pozzolanic During the hydration ofconcrete Ca (OH)2 was produced It reacted with activeSiO2 Fe2O3 and Al2O3 produced from the red mud in thesecond time hydration and generated the hydrate calcium
Pressure plate
Top plate (movable)
Bottom plate
Pressure plate
Transducers
SpecimenStrain gauges
N
N
Figure 4 Column test layout
1
24
3
Figure 5 Arrangement of the strain gauges measuring equipment
200
1010
Top plate (movable)
Top plate (movable)Specimen
Specimen
Specimen
Fillet weld
Bottom plate
200
200
200
10
3
D
D + 02
Top plate (movable)
Fillet weld
Bottom plate
200
200
ts
ts
L DD + 02
Figure 2 e specimens geometry
Figure 3 e loading device
4 Advances in Materials Science and Engineering
silicate and the hydrate calcium acuminate In the process ofthe reaction Ca (OH)2 generated was being consumedwhich caused further hydration reaction promoted estructure of the interface between the internal medium ofconcrete was improved e compressive strength of con-crete was enhanced and secondly the red mud particleswere finer after processing its specific surface area wasbigger than 400m2kg while the specific surface area of
Portland cement was only bigger than 300m2kg ereforethe red mud played a physical filling role in the concreteeconcrete mixing with the red mud would have smaller poresand lower porosity which caused the compactness of theconcrete was raised As a result the compressive strength ofthe concrete would be improved
As seen in Figure 9 with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stub
Note(1) e horizontal line is to keep the load unchanged for two minutes(2) Oblique straight line is the load that increases slowly
Figure 6 Simplified diagram of the method of load increment
Advances in Materials Science and Engineering 5
column the ultimate displacement of the specimens de-creased first and then increased the ultimate displacementwas minimum as r 5 the ultimate displacement of theCCFST with the red mud specimens for groups A B and Cwere 58mm 45mm and 33mm respectively decreased1077 1964 and 2667 than those 3 CCFSTspecimensAs r 20 the ultimate displacement of the CCFSTwith thered mud specimens for groups A B and C was 66mm59mm and 47mm respectively increased 154 536and 444 than the ultimate displacement of the 3 CCFSTspecimens Obviously when the quality substitution rate ofthe red mud was between 0sim20 the ultimate displace-ment of the CCFST with the red mud specimens decreasedand the ductility became weaker compared with the CCFSTspecimens the main reason of which was that the strength of
the CCFST mixing the red mud was improved and thestiffness was enhanced
33 Analysis of the Whole Process of Stress Strain enominal compressive stress of the specimen is σsc NAsc
σsc is the nominal compressive stress of the specimenN is the axial pressureAsc is the cross-sectional area of the specimen
e axial compressive strain of the specimen is εsl ΔL
εsl is the compressive strain of the specimenΔ is the axial deformationL is the height of the specimen
0
500
1000
1500N
(KN
)
0 5 10 15 20 25Δ (mm)
CSCA-1CSCA-2CSCA-3
CSCA-4CSCA-5
(a)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCB-4CSCB-5
CSCB-1CSCB-2CSCB-3
(b)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCC-1CSCC-2CSCC-3
CSCC-4CSCC-5
(c)
Figure 9 e load versus displacement curves (a) Group A (b) Group B (c) Group C
6 Advances in Materials Science and Engineering
According to Figure 8 the typical σsc minus εsl curves of thespecimens were obtained as shown in Figure 10
As can be seen from Figure 10 the curve mainly un-dergoes three stages elastic stage (OA) elastic-plastic stage(AB) and ascendingdescendinghorizontal stage (BC)
OA stage the curve is linear It indicates that the qualitysubstitution rate of the red mud has little effect on thestiffness when the specimen is in the elastic stage e steeltube and the red mud concrete have not been working welltogether When reaching point A the steel tube is in acompressive yield state the longitudinal strain is about1600 με the circumferential strain is around 450 με and thespecimen reaches the proportional limitation
AB stage the specimen is in the elastic-plastic stage andthe steel tube and the red mud concrete bear the load si-multaneously With the development of the red mud con-crete cracks in the steel tube the transverse deformationexceeds the Poissonrsquos ratio of the steel tube Mutual ex-trusion produced between these two materials causes thesteel tube to produce the confinement effect on the red mudconcrete core At the same time the redmud concrete core isin a three-dimensional compressive state erefore thebearing capacity of the specimen is enhanced As reachingpoint B the longitudinal strain of the steel tube is about4400sim5000 με and the specimen reaches the yield limitation
BC stage when it exceeds point B the curve is dividedinto three situations according to the different confiningfactor As ξs ξ0 the curve is basically horizontal as ξs gt ξ0it becomes a slowly rising curve the bigger the confiningfactor is the larger the rise range is and vice versa as ξs lt ξ0it is a gradually falling curve the smaller the confining factoris the larger the decline range is and vice versa Accordingto Table 4 and Figure 9 ξ0 11
4 Simplified Calculation of Axial CompressiveBearing Capacity
419eProposedEmpirical Formulation ofAxialCompressiveBearing Capacity of Stub Column According to Figure 9when the specimens reach the peak load the deformation is
too big e components would have lost their usagefunction if they were applied in the real projects ereforethe ultimate yield strength fscy of the specimen (longitu-dinal strain is about 4400ndash5000 με) determined by the stress-strain relations shown in Figure 10 is defined as the ultimatestrength of the axial compressive bearing capacity of thespecimen In the range of quality substitution rate of the redmud r 0sim20 regression analysis of test data is carriedout as shown in Figures 11 and 12
e formulation of fscy proposed by regression analysisis as follows
fscy φr 2094 + 0765ξs( 1113857fck (1)
en the axial compressive bearing capacity formula-tion of the CCFSTstub columnwith the redmud is proposedas follows
Nu fscyAsc (2)
φr 0993 minus 1480r + 8261r2 (3)
Asc As + Ac (4)
fscy is the ultimate strength of axial compressive bearingcapacity fckis the standard value of compressive strength ofconcrete fck 067fcu ξs is the confining factor of steeltube ξs (fyAsfckAc) Nuis the axial compressive bearingcapacity of stub column Ascis the composite section area ofCCFST stub column with red mud As is the section area ofsteel tube of CCFST stub column with red mud Ac is thesection area of concrete of CCFST stub column with redmud φr is the influence coefficient of quality substitutionrate of the red mud r is the quality substitution rate of thered mud
When r 0 it can be seen as the formulation of theaxial compressive bearing capacity of the CCFST stubcolumn
C
C
CB
Aξs lt ξ0
ξs gt ξ0
ξs = ξ0
εsl
σ sc
O
Figure 10 e σsc minus εsl relations of the specimens2
3
4
5
1 2 3
f scyf
ck
ξs
fscy = (2094 + 0765ξs)fck
Figure 11 e relationship between ultimate yield strength andconfining factor
Advances in Materials Science and Engineering 7
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
drum-shaped failure occurred (Figure 7) while the speci-mens showed good ductility After the ultimate load wasreached the bearing capacity of the specimens was differentaccording to the different confining factor For the speci-mens with big confining factor the bearing capacity wasslightly increased For the specimens with small confiningfactor the bearing capacity was slightly decreased For thespecimen with a moderate confining factor the bearingcapacity kept the same e deformation of the specimens inthose 3 situations was continuously increasing until thespecimens were loaded to failure e failure modality of the
CCFSTwith the red mud specimen was similar to the failuremodality of the CCFST specimen Figure 8 shows all thespecimens with failure mode
32 Influence of Mixed Red Mud e load (kN) versusdisplacement (mm) curves for the 3 groups specimens (A BC) are presented in Figure 9
As shown in Figure 9 the load (kN) versus axial dis-placement (mm) curves for the 3 series of specimens are littledifferent It was found that with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stubcolumn the ultimate load of specimens increased first andthen decreased e ultimate load was the maximum asr 5 the ultimate load on the CCFST with the red mudspecimens for groups A B and C were 10034 kN14036 kN and 18845 kN respectively which increased1330 884 and 1561 compared with those 3 CCFSTspecimens As r 20 the ultimate load on the CCFSTwiththe red mud specimens for groups A B and C were8605 kN 12656 kN and 1600 kN respectively which de-creased 283 186 and 185 than the ultimate load onthe 3 CCFST specimens It illustrates that when the qualitysubstitution rate of the red mud is between 0sim20 theultimate load on the CCFSTwith the red mud increases thereasons of which are twofold firstly the red mud has thecharacteristics of pozzolanic During the hydration ofconcrete Ca (OH)2 was produced It reacted with activeSiO2 Fe2O3 and Al2O3 produced from the red mud in thesecond time hydration and generated the hydrate calcium
Pressure plate
Top plate (movable)
Bottom plate
Pressure plate
Transducers
SpecimenStrain gauges
N
N
Figure 4 Column test layout
1
24
3
Figure 5 Arrangement of the strain gauges measuring equipment
200
1010
Top plate (movable)
Top plate (movable)Specimen
Specimen
Specimen
Fillet weld
Bottom plate
200
200
200
10
3
D
D + 02
Top plate (movable)
Fillet weld
Bottom plate
200
200
ts
ts
L DD + 02
Figure 2 e specimens geometry
Figure 3 e loading device
4 Advances in Materials Science and Engineering
silicate and the hydrate calcium acuminate In the process ofthe reaction Ca (OH)2 generated was being consumedwhich caused further hydration reaction promoted estructure of the interface between the internal medium ofconcrete was improved e compressive strength of con-crete was enhanced and secondly the red mud particleswere finer after processing its specific surface area wasbigger than 400m2kg while the specific surface area of
Portland cement was only bigger than 300m2kg ereforethe red mud played a physical filling role in the concreteeconcrete mixing with the red mud would have smaller poresand lower porosity which caused the compactness of theconcrete was raised As a result the compressive strength ofthe concrete would be improved
As seen in Figure 9 with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stub
Note(1) e horizontal line is to keep the load unchanged for two minutes(2) Oblique straight line is the load that increases slowly
Figure 6 Simplified diagram of the method of load increment
Advances in Materials Science and Engineering 5
column the ultimate displacement of the specimens de-creased first and then increased the ultimate displacementwas minimum as r 5 the ultimate displacement of theCCFST with the red mud specimens for groups A B and Cwere 58mm 45mm and 33mm respectively decreased1077 1964 and 2667 than those 3 CCFSTspecimensAs r 20 the ultimate displacement of the CCFSTwith thered mud specimens for groups A B and C was 66mm59mm and 47mm respectively increased 154 536and 444 than the ultimate displacement of the 3 CCFSTspecimens Obviously when the quality substitution rate ofthe red mud was between 0sim20 the ultimate displace-ment of the CCFST with the red mud specimens decreasedand the ductility became weaker compared with the CCFSTspecimens the main reason of which was that the strength of
the CCFST mixing the red mud was improved and thestiffness was enhanced
33 Analysis of the Whole Process of Stress Strain enominal compressive stress of the specimen is σsc NAsc
σsc is the nominal compressive stress of the specimenN is the axial pressureAsc is the cross-sectional area of the specimen
e axial compressive strain of the specimen is εsl ΔL
εsl is the compressive strain of the specimenΔ is the axial deformationL is the height of the specimen
0
500
1000
1500N
(KN
)
0 5 10 15 20 25Δ (mm)
CSCA-1CSCA-2CSCA-3
CSCA-4CSCA-5
(a)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCB-4CSCB-5
CSCB-1CSCB-2CSCB-3
(b)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCC-1CSCC-2CSCC-3
CSCC-4CSCC-5
(c)
Figure 9 e load versus displacement curves (a) Group A (b) Group B (c) Group C
6 Advances in Materials Science and Engineering
According to Figure 8 the typical σsc minus εsl curves of thespecimens were obtained as shown in Figure 10
As can be seen from Figure 10 the curve mainly un-dergoes three stages elastic stage (OA) elastic-plastic stage(AB) and ascendingdescendinghorizontal stage (BC)
OA stage the curve is linear It indicates that the qualitysubstitution rate of the red mud has little effect on thestiffness when the specimen is in the elastic stage e steeltube and the red mud concrete have not been working welltogether When reaching point A the steel tube is in acompressive yield state the longitudinal strain is about1600 με the circumferential strain is around 450 με and thespecimen reaches the proportional limitation
AB stage the specimen is in the elastic-plastic stage andthe steel tube and the red mud concrete bear the load si-multaneously With the development of the red mud con-crete cracks in the steel tube the transverse deformationexceeds the Poissonrsquos ratio of the steel tube Mutual ex-trusion produced between these two materials causes thesteel tube to produce the confinement effect on the red mudconcrete core At the same time the redmud concrete core isin a three-dimensional compressive state erefore thebearing capacity of the specimen is enhanced As reachingpoint B the longitudinal strain of the steel tube is about4400sim5000 με and the specimen reaches the yield limitation
BC stage when it exceeds point B the curve is dividedinto three situations according to the different confiningfactor As ξs ξ0 the curve is basically horizontal as ξs gt ξ0it becomes a slowly rising curve the bigger the confiningfactor is the larger the rise range is and vice versa as ξs lt ξ0it is a gradually falling curve the smaller the confining factoris the larger the decline range is and vice versa Accordingto Table 4 and Figure 9 ξ0 11
4 Simplified Calculation of Axial CompressiveBearing Capacity
419eProposedEmpirical Formulation ofAxialCompressiveBearing Capacity of Stub Column According to Figure 9when the specimens reach the peak load the deformation is
too big e components would have lost their usagefunction if they were applied in the real projects ereforethe ultimate yield strength fscy of the specimen (longitu-dinal strain is about 4400ndash5000 με) determined by the stress-strain relations shown in Figure 10 is defined as the ultimatestrength of the axial compressive bearing capacity of thespecimen In the range of quality substitution rate of the redmud r 0sim20 regression analysis of test data is carriedout as shown in Figures 11 and 12
e formulation of fscy proposed by regression analysisis as follows
fscy φr 2094 + 0765ξs( 1113857fck (1)
en the axial compressive bearing capacity formula-tion of the CCFSTstub columnwith the redmud is proposedas follows
Nu fscyAsc (2)
φr 0993 minus 1480r + 8261r2 (3)
Asc As + Ac (4)
fscy is the ultimate strength of axial compressive bearingcapacity fckis the standard value of compressive strength ofconcrete fck 067fcu ξs is the confining factor of steeltube ξs (fyAsfckAc) Nuis the axial compressive bearingcapacity of stub column Ascis the composite section area ofCCFST stub column with red mud As is the section area ofsteel tube of CCFST stub column with red mud Ac is thesection area of concrete of CCFST stub column with redmud φr is the influence coefficient of quality substitutionrate of the red mud r is the quality substitution rate of thered mud
When r 0 it can be seen as the formulation of theaxial compressive bearing capacity of the CCFST stubcolumn
C
C
CB
Aξs lt ξ0
ξs gt ξ0
ξs = ξ0
εsl
σ sc
O
Figure 10 e σsc minus εsl relations of the specimens2
3
4
5
1 2 3
f scyf
ck
ξs
fscy = (2094 + 0765ξs)fck
Figure 11 e relationship between ultimate yield strength andconfining factor
Advances in Materials Science and Engineering 7
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
silicate and the hydrate calcium acuminate In the process ofthe reaction Ca (OH)2 generated was being consumedwhich caused further hydration reaction promoted estructure of the interface between the internal medium ofconcrete was improved e compressive strength of con-crete was enhanced and secondly the red mud particleswere finer after processing its specific surface area wasbigger than 400m2kg while the specific surface area of
Portland cement was only bigger than 300m2kg ereforethe red mud played a physical filling role in the concreteeconcrete mixing with the red mud would have smaller poresand lower porosity which caused the compactness of theconcrete was raised As a result the compressive strength ofthe concrete would be improved
As seen in Figure 9 with the increase of the qualitysubstitution rate of the red mud (r) in the CCFST stub
Note(1) e horizontal line is to keep the load unchanged for two minutes(2) Oblique straight line is the load that increases slowly
Figure 6 Simplified diagram of the method of load increment
Advances in Materials Science and Engineering 5
column the ultimate displacement of the specimens de-creased first and then increased the ultimate displacementwas minimum as r 5 the ultimate displacement of theCCFST with the red mud specimens for groups A B and Cwere 58mm 45mm and 33mm respectively decreased1077 1964 and 2667 than those 3 CCFSTspecimensAs r 20 the ultimate displacement of the CCFSTwith thered mud specimens for groups A B and C was 66mm59mm and 47mm respectively increased 154 536and 444 than the ultimate displacement of the 3 CCFSTspecimens Obviously when the quality substitution rate ofthe red mud was between 0sim20 the ultimate displace-ment of the CCFST with the red mud specimens decreasedand the ductility became weaker compared with the CCFSTspecimens the main reason of which was that the strength of
the CCFST mixing the red mud was improved and thestiffness was enhanced
33 Analysis of the Whole Process of Stress Strain enominal compressive stress of the specimen is σsc NAsc
σsc is the nominal compressive stress of the specimenN is the axial pressureAsc is the cross-sectional area of the specimen
e axial compressive strain of the specimen is εsl ΔL
εsl is the compressive strain of the specimenΔ is the axial deformationL is the height of the specimen
0
500
1000
1500N
(KN
)
0 5 10 15 20 25Δ (mm)
CSCA-1CSCA-2CSCA-3
CSCA-4CSCA-5
(a)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCB-4CSCB-5
CSCB-1CSCB-2CSCB-3
(b)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCC-1CSCC-2CSCC-3
CSCC-4CSCC-5
(c)
Figure 9 e load versus displacement curves (a) Group A (b) Group B (c) Group C
6 Advances in Materials Science and Engineering
According to Figure 8 the typical σsc minus εsl curves of thespecimens were obtained as shown in Figure 10
As can be seen from Figure 10 the curve mainly un-dergoes three stages elastic stage (OA) elastic-plastic stage(AB) and ascendingdescendinghorizontal stage (BC)
OA stage the curve is linear It indicates that the qualitysubstitution rate of the red mud has little effect on thestiffness when the specimen is in the elastic stage e steeltube and the red mud concrete have not been working welltogether When reaching point A the steel tube is in acompressive yield state the longitudinal strain is about1600 με the circumferential strain is around 450 με and thespecimen reaches the proportional limitation
AB stage the specimen is in the elastic-plastic stage andthe steel tube and the red mud concrete bear the load si-multaneously With the development of the red mud con-crete cracks in the steel tube the transverse deformationexceeds the Poissonrsquos ratio of the steel tube Mutual ex-trusion produced between these two materials causes thesteel tube to produce the confinement effect on the red mudconcrete core At the same time the redmud concrete core isin a three-dimensional compressive state erefore thebearing capacity of the specimen is enhanced As reachingpoint B the longitudinal strain of the steel tube is about4400sim5000 με and the specimen reaches the yield limitation
BC stage when it exceeds point B the curve is dividedinto three situations according to the different confiningfactor As ξs ξ0 the curve is basically horizontal as ξs gt ξ0it becomes a slowly rising curve the bigger the confiningfactor is the larger the rise range is and vice versa as ξs lt ξ0it is a gradually falling curve the smaller the confining factoris the larger the decline range is and vice versa Accordingto Table 4 and Figure 9 ξ0 11
4 Simplified Calculation of Axial CompressiveBearing Capacity
419eProposedEmpirical Formulation ofAxialCompressiveBearing Capacity of Stub Column According to Figure 9when the specimens reach the peak load the deformation is
too big e components would have lost their usagefunction if they were applied in the real projects ereforethe ultimate yield strength fscy of the specimen (longitu-dinal strain is about 4400ndash5000 με) determined by the stress-strain relations shown in Figure 10 is defined as the ultimatestrength of the axial compressive bearing capacity of thespecimen In the range of quality substitution rate of the redmud r 0sim20 regression analysis of test data is carriedout as shown in Figures 11 and 12
e formulation of fscy proposed by regression analysisis as follows
fscy φr 2094 + 0765ξs( 1113857fck (1)
en the axial compressive bearing capacity formula-tion of the CCFSTstub columnwith the redmud is proposedas follows
Nu fscyAsc (2)
φr 0993 minus 1480r + 8261r2 (3)
Asc As + Ac (4)
fscy is the ultimate strength of axial compressive bearingcapacity fckis the standard value of compressive strength ofconcrete fck 067fcu ξs is the confining factor of steeltube ξs (fyAsfckAc) Nuis the axial compressive bearingcapacity of stub column Ascis the composite section area ofCCFST stub column with red mud As is the section area ofsteel tube of CCFST stub column with red mud Ac is thesection area of concrete of CCFST stub column with redmud φr is the influence coefficient of quality substitutionrate of the red mud r is the quality substitution rate of thered mud
When r 0 it can be seen as the formulation of theaxial compressive bearing capacity of the CCFST stubcolumn
C
C
CB
Aξs lt ξ0
ξs gt ξ0
ξs = ξ0
εsl
σ sc
O
Figure 10 e σsc minus εsl relations of the specimens2
3
4
5
1 2 3
f scyf
ck
ξs
fscy = (2094 + 0765ξs)fck
Figure 11 e relationship between ultimate yield strength andconfining factor
Advances in Materials Science and Engineering 7
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
column the ultimate displacement of the specimens de-creased first and then increased the ultimate displacementwas minimum as r 5 the ultimate displacement of theCCFST with the red mud specimens for groups A B and Cwere 58mm 45mm and 33mm respectively decreased1077 1964 and 2667 than those 3 CCFSTspecimensAs r 20 the ultimate displacement of the CCFSTwith thered mud specimens for groups A B and C was 66mm59mm and 47mm respectively increased 154 536and 444 than the ultimate displacement of the 3 CCFSTspecimens Obviously when the quality substitution rate ofthe red mud was between 0sim20 the ultimate displace-ment of the CCFST with the red mud specimens decreasedand the ductility became weaker compared with the CCFSTspecimens the main reason of which was that the strength of
the CCFST mixing the red mud was improved and thestiffness was enhanced
33 Analysis of the Whole Process of Stress Strain enominal compressive stress of the specimen is σsc NAsc
σsc is the nominal compressive stress of the specimenN is the axial pressureAsc is the cross-sectional area of the specimen
e axial compressive strain of the specimen is εsl ΔL
εsl is the compressive strain of the specimenΔ is the axial deformationL is the height of the specimen
0
500
1000
1500N
(KN
)
0 5 10 15 20 25Δ (mm)
CSCA-1CSCA-2CSCA-3
CSCA-4CSCA-5
(a)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCB-4CSCB-5
CSCB-1CSCB-2CSCB-3
(b)
0
700
1400
2100
N (K
N)
0 5 10 15 20 25Δ (mm)
CSCC-1CSCC-2CSCC-3
CSCC-4CSCC-5
(c)
Figure 9 e load versus displacement curves (a) Group A (b) Group B (c) Group C
6 Advances in Materials Science and Engineering
According to Figure 8 the typical σsc minus εsl curves of thespecimens were obtained as shown in Figure 10
As can be seen from Figure 10 the curve mainly un-dergoes three stages elastic stage (OA) elastic-plastic stage(AB) and ascendingdescendinghorizontal stage (BC)
OA stage the curve is linear It indicates that the qualitysubstitution rate of the red mud has little effect on thestiffness when the specimen is in the elastic stage e steeltube and the red mud concrete have not been working welltogether When reaching point A the steel tube is in acompressive yield state the longitudinal strain is about1600 με the circumferential strain is around 450 με and thespecimen reaches the proportional limitation
AB stage the specimen is in the elastic-plastic stage andthe steel tube and the red mud concrete bear the load si-multaneously With the development of the red mud con-crete cracks in the steel tube the transverse deformationexceeds the Poissonrsquos ratio of the steel tube Mutual ex-trusion produced between these two materials causes thesteel tube to produce the confinement effect on the red mudconcrete core At the same time the redmud concrete core isin a three-dimensional compressive state erefore thebearing capacity of the specimen is enhanced As reachingpoint B the longitudinal strain of the steel tube is about4400sim5000 με and the specimen reaches the yield limitation
BC stage when it exceeds point B the curve is dividedinto three situations according to the different confiningfactor As ξs ξ0 the curve is basically horizontal as ξs gt ξ0it becomes a slowly rising curve the bigger the confiningfactor is the larger the rise range is and vice versa as ξs lt ξ0it is a gradually falling curve the smaller the confining factoris the larger the decline range is and vice versa Accordingto Table 4 and Figure 9 ξ0 11
4 Simplified Calculation of Axial CompressiveBearing Capacity
419eProposedEmpirical Formulation ofAxialCompressiveBearing Capacity of Stub Column According to Figure 9when the specimens reach the peak load the deformation is
too big e components would have lost their usagefunction if they were applied in the real projects ereforethe ultimate yield strength fscy of the specimen (longitu-dinal strain is about 4400ndash5000 με) determined by the stress-strain relations shown in Figure 10 is defined as the ultimatestrength of the axial compressive bearing capacity of thespecimen In the range of quality substitution rate of the redmud r 0sim20 regression analysis of test data is carriedout as shown in Figures 11 and 12
e formulation of fscy proposed by regression analysisis as follows
fscy φr 2094 + 0765ξs( 1113857fck (1)
en the axial compressive bearing capacity formula-tion of the CCFSTstub columnwith the redmud is proposedas follows
Nu fscyAsc (2)
φr 0993 minus 1480r + 8261r2 (3)
Asc As + Ac (4)
fscy is the ultimate strength of axial compressive bearingcapacity fckis the standard value of compressive strength ofconcrete fck 067fcu ξs is the confining factor of steeltube ξs (fyAsfckAc) Nuis the axial compressive bearingcapacity of stub column Ascis the composite section area ofCCFST stub column with red mud As is the section area ofsteel tube of CCFST stub column with red mud Ac is thesection area of concrete of CCFST stub column with redmud φr is the influence coefficient of quality substitutionrate of the red mud r is the quality substitution rate of thered mud
When r 0 it can be seen as the formulation of theaxial compressive bearing capacity of the CCFST stubcolumn
C
C
CB
Aξs lt ξ0
ξs gt ξ0
ξs = ξ0
εsl
σ sc
O
Figure 10 e σsc minus εsl relations of the specimens2
3
4
5
1 2 3
f scyf
ck
ξs
fscy = (2094 + 0765ξs)fck
Figure 11 e relationship between ultimate yield strength andconfining factor
Advances in Materials Science and Engineering 7
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
According to Figure 8 the typical σsc minus εsl curves of thespecimens were obtained as shown in Figure 10
As can be seen from Figure 10 the curve mainly un-dergoes three stages elastic stage (OA) elastic-plastic stage(AB) and ascendingdescendinghorizontal stage (BC)
OA stage the curve is linear It indicates that the qualitysubstitution rate of the red mud has little effect on thestiffness when the specimen is in the elastic stage e steeltube and the red mud concrete have not been working welltogether When reaching point A the steel tube is in acompressive yield state the longitudinal strain is about1600 με the circumferential strain is around 450 με and thespecimen reaches the proportional limitation
AB stage the specimen is in the elastic-plastic stage andthe steel tube and the red mud concrete bear the load si-multaneously With the development of the red mud con-crete cracks in the steel tube the transverse deformationexceeds the Poissonrsquos ratio of the steel tube Mutual ex-trusion produced between these two materials causes thesteel tube to produce the confinement effect on the red mudconcrete core At the same time the redmud concrete core isin a three-dimensional compressive state erefore thebearing capacity of the specimen is enhanced As reachingpoint B the longitudinal strain of the steel tube is about4400sim5000 με and the specimen reaches the yield limitation
BC stage when it exceeds point B the curve is dividedinto three situations according to the different confiningfactor As ξs ξ0 the curve is basically horizontal as ξs gt ξ0it becomes a slowly rising curve the bigger the confiningfactor is the larger the rise range is and vice versa as ξs lt ξ0it is a gradually falling curve the smaller the confining factoris the larger the decline range is and vice versa Accordingto Table 4 and Figure 9 ξ0 11
4 Simplified Calculation of Axial CompressiveBearing Capacity
419eProposedEmpirical Formulation ofAxialCompressiveBearing Capacity of Stub Column According to Figure 9when the specimens reach the peak load the deformation is
too big e components would have lost their usagefunction if they were applied in the real projects ereforethe ultimate yield strength fscy of the specimen (longitu-dinal strain is about 4400ndash5000 με) determined by the stress-strain relations shown in Figure 10 is defined as the ultimatestrength of the axial compressive bearing capacity of thespecimen In the range of quality substitution rate of the redmud r 0sim20 regression analysis of test data is carriedout as shown in Figures 11 and 12
e formulation of fscy proposed by regression analysisis as follows
fscy φr 2094 + 0765ξs( 1113857fck (1)
en the axial compressive bearing capacity formula-tion of the CCFSTstub columnwith the redmud is proposedas follows
Nu fscyAsc (2)
φr 0993 minus 1480r + 8261r2 (3)
Asc As + Ac (4)
fscy is the ultimate strength of axial compressive bearingcapacity fckis the standard value of compressive strength ofconcrete fck 067fcu ξs is the confining factor of steeltube ξs (fyAsfckAc) Nuis the axial compressive bearingcapacity of stub column Ascis the composite section area ofCCFST stub column with red mud As is the section area ofsteel tube of CCFST stub column with red mud Ac is thesection area of concrete of CCFST stub column with redmud φr is the influence coefficient of quality substitutionrate of the red mud r is the quality substitution rate of thered mud
When r 0 it can be seen as the formulation of theaxial compressive bearing capacity of the CCFST stubcolumn
C
C
CB
Aξs lt ξ0
ξs gt ξ0
ξs = ξ0
εsl
σ sc
O
Figure 10 e σsc minus εsl relations of the specimens2
3
4
5
1 2 3
f scyf
ck
ξs
fscy = (2094 + 0765ξs)fck
Figure 11 e relationship between ultimate yield strength andconfining factor
Advances in Materials Science and Engineering 7
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
000 005 010 015 020
09
10
r
φ r
φr = 0993 ndash 1480r + 8261r2
Figure 12 e relationship between ultimate yield strength and quality substitution rate of the red mud
0
500
500
1000
1000
1500
1500
2000
2000
Nuc (K
N)
0Nu
e (KN)
CSCACSCBCSCC
(a)
Figure 13 Continued
8 Advances in Materials Science and Engineering
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
42 Validation of the Proposed Empirical Formulation Inorder to verify the correctness of the proposed empiricalformulation the calculated results from formula (2) shownabove were compared with test data of fifteen specimens ascan be seen in Figure 13(a) It was found that the mean valuethe standard deviation and the variation coefficient of theCCFST stub columns with the red mud Nc
uNeu were 0989
0024 and 0024 respectively e result indicates that ingeneral the theoretical values of the axial compressivebearing capacity of stub columns agree well with the ex-perimental data
Due to the limited experimental data of 15 CCFST stubcolumns with the red mud the additional experimental dataof a total of 325 CCFST stub columns specimens (r 0)from references [1ndash8 21ndash29] were introduced in order tofurther validate the proposed formulation and were com-pared with the calculated value from formula (2) as can beseen in Figure 13(b) It was found that the mean value thestandard deviation and the variation coefficient of CCFSTstub columns Nc
uNeu were 0938 0141 and 0150 respec-
tively In the same way the theoretical value of the axialcompressive bearing capacity of the stub column agrees wellwith the experimental data as well
erefore formula (2) is applicable to the calculation ofaxial compressive bearing capacity for the CCFST stubcolumns with the red mud (as r 0 for the CCFST stubcolumns) Formula calculation value is generally safe andsuitable for engineering application
5 Conclusions
Based on the results of this study the following conclusionscan be drawn
(1) with the increase of the quality substitution rate ofthe red mud (r 0sim20) in the CCFST stub col-umn with the red mud the ultimate load increasesfirst and then decreases on the contrary the ultimatedisplacement decreases first then increases the ul-timate load is maximum as r 5 while the ulti-mate displacement is minimum as r 20 theultimate load and the ultimate displacement are bothnearly the same respectively as r 0
(2) As the longitudinal strain of the steel tube is about1600 με the specimen reaches the proportionallimitation as the longitudinal strain of steel tube isabout 4400sim5000 με the specimen reaches the yieldlimitation When it exceeds yield limitation asξs ξ0 the curve is basically horizontal as ξs gt ξ0 itbecomes a slowly rising curve as ξs lt ξ0 it is agradually falling curve ξ0 11
(3) Empirical formulation of axial compressive bearingcapacity of the CCFST stub columns with the redmud is proposed with clear expression and it issuitable for engineering application
(4) e experimental data of total 340 specimens in-cluding 15 specimens shown in this paper were
Figure 13 e comparison of calculated result and experiment result of axial compressive bearing capacity
Advances in Materials Science and Engineering 9
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
compared with calculated results from formula (2)e calculated results agree well with the experi-mental data which approve the correctness of theempirical formulation
Data Availability
e literature data used to support the findings of this studyhave been deposited in the CNKI and Duxiu AcademicSearch repositories (ISBN7-03-012871-0 ISBN 978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN 0733-9445000011-1295ndash1303 ISSN1708-5284 101061(ASCE)ST1943-541X0002474 doiorg101016jjcsr200310001 doiorg101061(ASCE)0733-9445(2004)1302(180) doiorg101016jtws200710001 doiorg101016jtws201604004) e test data used to support the findingsof this study are included within the article Previouslyreported literature data were used to support this studyand are available at (ISBN7-03-012871-0 ISBN978-7-114-06393-0 ISBN7-5611-1071-5 1014006jjzjgxb2002020061014006jjzjgxb1999010021015951jtmgcxb2004090011014006jjzjgxb2017S1034 doi101016jjcsr200310001ISSN0733-9445000011-1295ndash1303ISSN1708-5284101061(ASCEST1943-541X0002474doiorg101016jjcsr200310001doiorg101061(ASCE)0733-9445(2004)1302(180)doiorg101016jtws200710001doiorg101016jtws201604004) ese prior studies (and datasets) arecited at relevant places within the text as references [1sim8]and [21sim30]
Conflicts of Interest
e authors declare that they have no conflicts of interest
Acknowledgments
is work was financially supported by the National NaturalScience Foundation of China (51574015) Liaoning ProvincePHD Startup Fund (20170520139) Liaoning Province ldquoXin-gliao Talent Programrdquo Project (XLYC1906010) and LiaoningProvincial Communications Technical College 2019 Tech-nology Applied Research Funding Project (LNCCjyky201918)
References
[1] L H Han Concrete Filled Steel Tubular structures SciencePress Beijing China 2nd edition 2007
[2] S H Cai Modern Steel Tube Confined Concrete structuresChina Communications Press Beijing China 2nd edition2007
[3] L H Han and S T Zhong Concrete Filled Steel TubeMechanics Dalian University of Technology Press DalianChina 2nd edition 1996
[4] Z Yu F Ding and L Song ldquoResearches on behavior of high-performance concrete filied tubular steel short columnsrdquoJournal of Building Structures vol 23 no 2 pp 41ndash47 2002
[5] K Tan X Pu and S Cai ldquoStudy on the mechanical propertiesof steel extra-high strength concrete encased in steel tubesrdquoJournal of Building Structures vol 20 no 1 pp 10ndash15 1999
[6] S Zhang and YWang ldquoFailure mode of short colums of high-strength concrete-filled steel tubesrdquo China Civil EngineeringJournal vol 37 no 9 pp 1ndash10 2004
[7] K Sakino H Nakahara and S Morino ldquoBehavior of centrallyloaded concrete-filled steel-tube short columnsrdquo Journal ofStructural Engineering vol 130 no 2 pp 180ndash188 2004
[8] P Nishiyama Y Wang C Liu et al ldquoExperimental study onsize effect of circular concrete-filled steel tubular columnssubjected to axial compressionrdquo Journal of Building Struc-tures vol 38 no S1 pp 249ndash257 2017
[9] J Xiao Q Zhang J Yu et al ldquoA novel development of concretestructures Composite concrete structuresrdquo Journal of TongjiUniversity (Natural Science) vol 46 no 2 pp 147ndash155 2018
[10] J Xiao Z Lin and J Zhu ldquoEffects of recycled aggregatesrsquogradation on compressive strength of concreterdquo Journal ofSichuan University (Engineering Science Edition) vol 46no 4 pp 154ndash160 2014
[11] S Omary E Ghorbel andW George ldquoRelationships betweenrecycled concrete aggregates characteristics and recycledaggregates concretes propertiesrdquo Construction and BuildingMaterials vol 108 pp 163ndash174 2016
[12] M Zhou S Tian T Guo et al ldquoExperimental research on theconcrete using spontaneous combustion gangue as full activematerialrdquo Bulletin of the Chinese Ceramic Society vol 30no 5 pp 1221ndash1226 2011
[13] L Yan-hua Li Liang and Q-xin Ren ldquoMechanical propertiesof rubber concrete-filled square steel tubular stub columnssubjected to axial loadingrdquo Journal of Northeastern University(Natural Science) vol 32 no 8 pp 1198ndash1209 2011
[14] J Chen Y Wang C W Roeder and J Ma ldquoBehavior ofnormal-strength recycled aggregate concrete filled steel tubesunder combined loadingrdquo Engineering Structures vol 130pp 23ndash40 2017
[15] L Ma and Z Shan-tong ldquoStrength and lateral deformationcoefficient of gangue concrete restrained by steel tuberdquoJournal of Harbin University of C EampArchitecture vol 35no 3 pp 20ndash23 2002
[16] A Silva Y Jiang J M Castro N Silvestre and R MonteiroldquoMonotonic and cyclic flexural behaviour of squarerectan-gular rubberized concrete-filled steel tubesrdquo Journal ofConstructional Steel Research vol 139 pp 385ndash396 2017
[17] W Liu J Yang and B Xiao ldquoReview on treatment andutilization of bauxite residues in Chinardquo International Journalof Mineral Processing vol 93 no 3-4 pp 220ndash231 2009
[18] X Liu N Zhang and H Sun ldquoStructural investigation re-lating to the cementitious activity of bauxite residue-Redmudrdquo Cement and Concrete Research vol 41 no 8pp 847ndash853 2011
[19] R-X Liu and C-S Poon ldquoUtilization of red mud derived frombauxite in self-compacting concreterdquo Journal of CleanerProduction vol 112 pp 384ndash391 2016
[20] B Wu Z Tan Y Zhang Z Zhao C Liu and Q WangldquoExperiment research on the bond-slip behavior of red mudconcrete filled square steel tubesrdquo Journal of Henan PolytechnicUniversity (Natural Science) vol 38 no 4 pp 148ndash153 2019
[21] G Giakoumelis and D Lam ldquoAxial capacity of circularconcrete-filled tube columnsrdquo Journal of Constructional Steelresearch vol 60 pp 1049ndash1068 2004
[22] D Lam and C Roach ldquoAxial capacity of concrete filledstainless steel circular columnsrdquo Welding in the Worldvol 50 pp 448ndash454 2007
[23] M D OrsquoShea and R Q Bridge ldquoDesign of circular thin-walledconcrete filled steel tubesrdquo Journal of Structural Engineeringvol 126 no 11 pp 1295ndash1303 2000
10 Advances in Materials Science and Engineering
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
Advances in Materials Science and Engineering 11
[24] M Mimoune F Z Mimoune and M Ait Youcef ldquoAxialcapacity of circular concrete-filled steel tube columnsrdquoWorldJournal of Engineering vol 8 no 3 pp 237ndash244 2011
[25] J Wei X Luo Z Lai and A H Varma ldquoExperimental be-havior and design of high-strength circular concrete-filledsteel tube short columnsrdquo Journal of Structural Engineeringvol 146 no 1 pp 1ndash16 Article ID 04019184 2020
[26] N J Gardner and R Jacobson ldquoStructural behavior ofconcrete filled steel tubesrdquo ACI Journal vol 64 no 7pp 404ndash413 1967
[27] G Giakoumelis and D Lam ldquoAxial capacity of circularconcretefilled tube columnsrdquo Journal of Constructional SteelResearch vol 60 no 7 pp 1049ndash1068 2004
[28] Q Yu Z Tao and Y-XWu ldquoExperimental behaviour of highperformance concrete-filled steel tubular columnsrdquo 9inWalled Structres vol 46 no 4 pp 362ndash370 2008
[29] T Ekmekyapar and B J M Al-Eliwi ldquoExperimental behav-iour of circular concrete filled steel tube columns and designspecificationsrdquo 9in Walled Structures vol 105 no 8pp 220ndash330 2016
