Ippei MARUYAMA, NAGOYA UNIV.
UNDERSTANDING OF CONCRETE STRUCTURE: MULTI-SCALE OBSERVATIONS AND MODELING IPPEI MARUYAMA NAGOYA UNIV. SYSTEMIZATION OF CONCRETE SCIENCE AND TECHNOLOGY THROUGH MULTI-SCALE MODELING 13RD JULY, 2015
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Ippei MARUYAMA, NAGOYA UNIV.
MULTI-SCALE PROBLEM • Long-term service of concrete structures is required by many
reasons. (Economical, Environmental (CO2, saving materials))
• Maintenance / Aging management is required.
• The knowledge of Maintenance / Aging management should contribute to the design of new structures.
• In matured society, extension of service life of concrete structure is more important rather than re-build the structures. Especially in case of Japan, which is under decreasing in population.
• Sensing and monitoring are applied to many structures for evaluating structural performance, damage or deterioration of reinforced concrete members.
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NEW PROBLEM OBSERVED IN MONITORING : ONAGAWA NPP
Onagawa NPP-3 was suffered from several (relatively large) earthquakes. Based on the monitoring results of accelerometer or velocimeter, modes of vibration are evaluated and natural frequencies were obtained.
Even though, all the earthquakes were found that they did not affect the structural cracking of quake resisting walls according to the design basis evaluation, 1st mode natural frequency of structure was decreased.
0 2 4 6 8 100
0.2
0.4
0.6
0.8
1
Rel
ativ
e na
tura
l fre
quen
cy (T
/To)
Years after constructionSimulation results of nuclear power plant building 2 and 3 in Onagawa site of Tohoku electric power company, Nuclear and Industrial Safety Agency Japan, 2011 (in Japanese). 3
Ippei MARUYAMA, NAGOYA UNIV.
NEW PROBLEM OBSERVED IN MONITORING : 8-STORY BRI BLDG
Building Research Institute, they have 8-story steel-reinforced concrete building. It contains many kinds of monitoring system and using the monitoring data, the change in natural frequency has been detected.
The trend is very similar to that of Onagawa NPP-3.
0 2 4 6 8 100
0.2
0.4
0.6
0.8
1
Rel
ativ
e na
tura
l fre
quen
cy (T
/To)
Years after construction
Onagawa-1 NPP BLI-building
T. Kashima, Y. Kitagawa, Dynamic characteristics of a building estimated from strong motion records using evolution strategy, J. Struct. Const. Eng. AIJ, 602 (2006) 4
Onagawa NPP-3
Ippei MARUYAMA, NAGOYA UNIV.
NEW PROBLEM OBSERVED IN MONITORING : 8-STORY BLDG
It is also confirmed that this decreasing trend is observed between earthquakes. During the every earthquakes, there is no damage, except for Tohoku-earthquake.
L. Li, A. Nakamura, T. Kashima, M. Teshigawara, EARTHQUAKE DAMAGE EVALUATION OF AN 8-STORY STEEL-REINFORCED CONCRETE BUILDING USING Sa-Sd CURVES, J Struct Constr Eng, 79 (2014) 1107-1115. 5
Ippei MARUYAMA, NAGOYA UNIV.
POSSIBLE IMPACT - For high-rise building, the decreasing of natural frequency
of building may cause to resonance, even wide range of frequency is considered in design state. System controlling is needed for compensating large seismic deformation.
- For nuclear power plant, supporting system is important. Resonance with piping system, cable system, or other facilities introduced in the plant are important issue. 2nd mode of structure might arise the problem. Aging management is important.
- Fundamental mechanism understanding and prediction is needed for aging management.
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Ippei MARUYAMA, NAGOYA UNIV.
PASTE-AGGREGATE-CONCRETE
PASTE C-S-H, Mesoscale structural compaction
+ Dehydration of C-S-H from interlayer and
resultant strength change
Strength Shrinkage
Aggregate
Mineralogical composition
Shrinkage Stiffness, Strength
Damage in concrete
Concrete stiffness
Concrete shrinkage
Stiffness
Cracking in member
Stiffness of member 7
Ippei MARUYAMA, NAGOYA UNIV.
SHRINKAGE OF PASTE
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Ippei MARUYAMA, NAGOYA UNIV.
IRREVERSIBLE SHRINKAGE
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0 0.2 0.4 0.6 0.8 1-0.006
-0.005
-0.004
-0.003
-0.002
-0.001
0
Relative humidity (p/p0)
Stra
in (m
/m)
N55
I. Maruyama, Origin of Drying Shrinkage of Hardened Cement Paste: Hydration pressure, Journal of Advanced Concrete Technology, Vol. 8, No. 2, pp.187-200, 2010.6
Ippei MARUYAMA, NAGOYA UNIV.
MECHANISM OF SHRINKAGE IN FIRST DESORPTION
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-0.016
-0.014
-0.012
-0.01
-0.008
-0.006
-0.004
-0.002
0
0 0.5 1 1.5 2
Shr
inka
ge s
train
(x10
-6)
Statistical thickness of adsorption (nm)
- Where disjoining pressure acts? - Long-term shrinkage is always liner function of statistical
thickness of adsorption.
0 0.2 0.4 0.6 0.8 1-0.006
-0.005
-0.004
-0.003
-0.002
-0.001
0
Relative humidity (p/p0)
Stra
in (m
/m)
N55
I. Maruyama, Origin of Drying Shrinkage of Hardened Cement Paste: Hydration pressure, Journal of Advanced Concrete Technology, Vol. 8, No. 2, pp.187-200, 2010.6
Ippei MARUYAMA, NAGOYA UNIV.
DIFFERENT SHRINKAGE WITH DIFFERENT PRE-DRYING
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SDSXX: Slowly (more than 1 year ) Dried Sample at XX %RH.
Ippei MARUYAMA, NAGOYA UNIV.
DIFFERENT SHRINKAGE WITH DIFFERENT PRE-DRYING -Shrinkage of paste with different RH pre-drying showed different shrinkage strain = different irreversible shrinkage. - Shrinkage 40-98%RH shows good correlation with incremental statistical thickness of adsorption at 40-98% RH.
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Maruyama, I., G. Igarashi and Y. Nishioka (2015). "Bimodal behavior of C-S-H interpreted from short-term length change and water vapor sorption isotherms of hardened cement paste." Cement and Concrete Research 73 0 158-168.
Ippei MARUYAMA, NAGOYA UNIV.
SHRINKAGE IN LOW RH AREA - Shrinkage strain under 40% RH is high correlation with water vapor BET surface area of hcp.
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3l S
l Eρ σ∆ ⋅
= ⋅ ∆
S
Maruyama, I., G. Igarashi and Y. Nishioka (2015). "Bimodal behavior of C-S-H interpreted from short-term length change and water vapor sorption isotherms of hardened cement paste." Cement and Concrete Research 73 0 158-168.
Ippei MARUYAMA, NAGOYA UNIV.
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Sorption potential contour
- From the 1H-NMR experiment, matured cement paste does not contain capillary water. (Muller et al.)
- In the interlayer, sorption potentials from both planes are overlapped. Sorption potential is higher in interlayer.
WHERE IS WATER?
1) Muller et al., The Journal of Physical Chemistry C, Vol.117, No.1, pp.403-412 (2013)
2) G. Igarashi, 2014, Behavior of Water Vapor Adsorption on Calcium Silicate Hydrate in Portland Cement Pastes, dissertation, Nagoya university.
*1
*2
Ippei MARUYAMA, NAGOYA UNIV.
TWO POSSIBILITY ~90% RH
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A: Gel and constant layer disctance
B: Movable layer distance *2
Feldman model
2) Maruyama, I., G. Igarashi and Y. Nishioka (2015). "Bimodal behavior of C-S-H interpreted from short-term length change and water vapor sorption isotherms of hardened cement paste." Cement and Concrete Research 73 0 158-168.
1) R.F. Feldman, Sorption and length-Change scanning isotherms of methanol and water on hydrated portland cement in: Fifth international symposium on the chemistry of cement, Tokyo, 1968, pp. 53-66.
*1
3) G. Igarashi, 2014, Behavior of Water Vapor Adsorption on Calcium Silicate Hydrate in Portland Cement Pastes, dissertation, Nagoya university.
*3
Ippei MARUYAMA, NAGOYA UNIV.
SHRINKAGE OF AGGREGATE
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Ippei MARUYAMA, NAGOYA UNIV.
SILICIOUS AGGREGATE - Aggregate in concrete shows
considerable shrinkage and it affects on shrinkage of concrete (Roper, PCA, 1960) as well as other physical properties of concrete.
- Sedimentary silicious rocks are used in Japan, but they show wide range in properties.
- Various and typical rocks are investigated.
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Submitted to Construction and Building Materials
Ippei MARUYAMA, NAGOYA UNIV.
SHRINKAGE OF AGGREGATE - Short-term length- change isotherms with orthogonal 3-
directions were recorded.
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Submitted to Construction and Building Materials
Ippei MARUYAMA, NAGOYA UNIV.
COMPONENTS OF AGGREGATE - Powder XRD / Rietveld analysis was conducted.
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Submitted to Construction and Building Materials
Ippei MARUYAMA, NAGOYA UNIV.
CORRELATION - Strong correlation is obtained between amount of chlorite
and shrinkage strain. - Weathering and resultant chlorite, not Illite or Sericite,
cause shrinkage in matrix, and produce macroscopic shrinkage of aggregate.
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Submitted to Construction and Building Materials
Ippei MARUYAMA, NAGOYA UNIV.
INTERACTION BETWEEN AGGREGATE AND MATRIX
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Ippei MARUYAMA, NAGOYA UNIV.
DAMAGE IN CONCRETE - Heterogeneous behaver between coarse aggregate and
matrix must be observed. - Damage behavior is detected by Digital Image Correlation
Method (DICM).
23 Max. principle strain dist. Results of fluor-epoxy intrusion method
I.Maruyama,H.Sasano,Strain and crack distribution in concrete during drying,Materials and Structures,2014
Ippei MARUYAMA, NAGOYA UNIV.
DIFFERENCE IN SHRINKAGE
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I. Maruyama, O. Kontani, A. Ishizawa, M. Takizawa, O. Sato: Development of System for Evaluating Concrete Strength Deterioration Due to Radiation and Resultant Heat, 3rd International Conference on NPP Life Management for Long Term Operations, IAEA-CN-194-096, Salt Lake City, USA, 12-14 May 2012.
Ippei MARUYAMA, NAGOYA UNIV.
0 1 2 3 4 5 6 7 8 9-1500
-1000
-500
0
Drying period (days)
Dry
ing
shrin
kage
(µ)
ROLE OF COARSE AGGREGATE (1)
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φ100mm
9 mm-thick
Mortor
Sandstone
Limestone LIMESTONE
SANDSTONE H. Sasano, N. Horiguchi, i. Maruyama, Evaluation of strain distribution and microcrack in concrete due to drying, Proceedings of Japan Concrete Institute, 34 (2012) 454-459.
Ippei MARUYAMA, NAGOYA UNIV.
SHRINKAGE OF CONCRETES - Concretes with different type of coarse aggregate is investigated. They are equilibrated with different drying condition.
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I. Maruyama, H. Sasano, Y. Nishioka, G. Igarashi, Strength and Young's modulus change in concrete due to long-term drying and heating up to 90 °C, Cement and Concrete Research, 66 (2014) 48-63.
Ippei MARUYAMA, NAGOYA UNIV.
DAMAGES IN CONCRETE
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I. Maruyama, H. Sasano, Y. Nishioka, G. Igarashi, Strength and Young's modulus change in concrete due to long-term drying and heating up to 90 °C, Cement and Concrete Research, 66 (2014) 48-63.
Ippei MARUYAMA, NAGOYA UNIV.
YOUNG’S MODULUS
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□G1:Limestone L. Sh. Gmax: 20 mm ■G2:Sandstone S Sh. Gmax: 20 mm ▽G3:Altared tuff. S. Sh. Gmax: 20 mm ▼G4:Altared tuff. S. Sh. Gmax 13 mm ○G5:River sand S. Sh. Gmax: 20mm
paste
I. Maruyama, H. Sasano, Y. Nishioka, G. Igarashi, Strength and Young's modulus change in concrete due to long-term drying and heating up to 90 °C, Cement and Concrete Research, 66 (2014) 48-63.
Ippei MARUYAMA, NAGOYA UNIV.
MECHANISM
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Mortar / Concretes
Concrete
Mortar
I. Maruyama, H. Sasano, Y. Nishioka, G. Igarashi, Strength and Young's modulus change in concrete due to long-term drying and heating up to 90 °C, Cement and Concrete Research, 66 (2014) 48-63.
Ippei MARUYAMA, NAGOYA UNIV.
MECHANISM
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Cracked parts indicates the voids in concrete
I. Maruyama, H. Sasano, Y. Nishioka, G. Igarashi, Strength and Young's modulus change in concrete due to long-term drying and heating up to 90 °C, Cement and Concrete Research, 66 (2014) 48-63.
Ippei MARUYAMA, NAGOYA UNIV.
DISCUSSION: ADDITIONAL DEFORMATION
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εe
εcr,b
εcr,dry
Neville’s schematic figure Modified
εe
εcr ≈ εcr,dry
εe: is increased due to micro-cracking or reduction of Young’s modulus
εcr > εcr,b
ε ε
Time Time
εcr is incresed due to localized and stress re-distribution in concrete due to cracks
Ippei MARUYAMA, NAGOYA UNIV.
TEST BY DAVIS ET AL.
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00.5
11.5
22.5
33.5
4
0.01 0.1 1 10 100
Cree
p c
oeff
icie
nt
Time under load (years)
Wet70%RH50%RH
0
0.5
1
1.5
2
2.5
3
3.5
100% RH 70% RH 50% RH
Cree
p co
effic
ient
Stress re-distributionYoung's modulus reductionFundamental
Localized and additional stress is produced in compression stress pass.
Averaged elastic impact of crack
Localized long-term impact of crack
1) E.D. Raymond, E.D. Harmer, Flow Of Concrete Under the Action of Sustained loads, Journal Proceedings, 27.
Ref 1)
Ippei MARUYAMA, NAGOYA UNIV.
VISIBLE AND INVISIBLE CRACKING
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CRACKING OF RC MEMBER
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Restraint body (Ratio of area:38.5%) Strain gauge
Deformed rebar D10 (Reinforcement ratio : 0.5%) Unit : mm
Dry
ing
shrin
kage
(x10
-6)
Time after drying (days)
- Drying shrinkage induced cracking behavior of concrete showing different shrinkage strain is investigated.
- PL1: Large shrinkage (1100µ), PL2: Moderate shrinkage (950µ), and PL3 Low shrinkage: (750µ)
Y. Mitani, Y. Ishii, M. Tanimura, I. Maruyama, Quantitative evaluation on reduction effect of drying shrinkage cracks by expansive additive, in: AIJ (Ed.) Summaries of technical papers of annual meeting, Nagoya, Japan, 2012, pp. 747-748.
Ippei MARUYAMA, NAGOYA UNIV.
CRACKING OF RC MEMBER
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Unit : mm
Dry
ing
shrin
kage
(x10
-6)
Time after drying (days)
Y. Mitani, Y. Ishii, M. Tanimura, I. Maruyama, Quantitative evaluation on reduction effect of drying shrinkage cracks by expansive additive, in: AIJ (Ed.) Summaries of technical papers of annual meeting, Nagoya, Japan, 2012, pp. 747-748.
- Volumetric mixture proportions were the same. Stress in mortar must be the same among specimens under the same drying and geometrical condition. Why visible cracks were differed under the same condition?
Ippei MARUYAMA, NAGOYA UNIV.
STRUCTURAL BEHAVIOR
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Ippei MARUYAMA, NAGOYA UNIV.
TARGET MEMBER
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・Wall:T=180mm, Reinforcement:0.40%, D13 ・Columns: 850×600mm, Reinforcement:1.59% ・Beam: 850×450mm, Reinforcement:1.32%
Upper rebar:5-D25 Bottom rebar:5-D25
6900
850 5200 850
850
2200 3050
単位(mm)
450
850
850
600
Wall thickness is 18cm or 60cm
A. Sugie, I. Maruyama, M. Teshigawara, 21588 Numerical simulation for stiffness change of RC wall due to drying, Summaries of technical papers of annual meeting, 2014 (2014) 1175-1176.
Ippei MARUYAMA, NAGOYA UNIV.
MODEL - 2-D Isoparametric elements for concrete
•Smeared crack model •Tension: ¼- softening model. •Shear softening: Walraven’s model •Shrinkage is considered as equivalent nodal force.
- Line-element for reinforcement
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CRACK AND MODEL - Crack size is 1/4 of Mesh size (gauss point.) - Crack less than 1/4 Mesh should be considered in
constitutive low. Reduction of Young’s modulus is modeled as a function of water content. Creep coefficient is modeled as a function of water content.
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Ippei MARUYAMA, NAGOYA UNIV.
CALCULATION PROCEDURE
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A. Sugie, I. Maruyama, M. Teshigawara, 21588 Numerical simulation for stiffness change of RC wall due to drying, Summaries of technical papers of annual meeting, 2014 (2014) 1175-1176.
Ippei MARUYAMA, NAGOYA UNIV.
CRACKS IN CASE OF LARGE SHRINKAGE CONCRETE
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A. Sugie, I. Maruyama, M. Teshigawara, 21588 Numerical simulation for stiffness change of RC wall due to drying, Summaries of technical papers of annual meeting, 2014 (2014) 1175-1176.
Ippei MARUYAMA, NAGOYA UNIV.
STIFFNESS
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0 0.5 1 1.50
1000
2000
3000
4000
水平変位(mm)
荷重
(kN
)
0 0.5 1 1.50
1000
2000
3000
4000
水平変位(mm)
荷重
(kN
)
Initial 28day91day 1year3year 10year理論式
LOAD
(kN
)
DEFORMATION (mm)
Initial
After 10 years
A. Sugie, I. Maruyama, M. Teshigawara, 21588 Numerical simulation for stiffness change of RC wall due to drying, Summaries of technical papers of annual meeting, 2014 (2014) 1175-1176.
Ippei MARUYAMA, NAGOYA UNIV.
COMPARISON
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12
kfmπ
=
剛性
質量 固有振動数
0 2 4 6 8 100
0.2
0.4
0.6
0.8
1
各乾燥期間の固有振動数
/In
itial
(竣工時
)の固有振動数
(-)
year
C-G1C-G2C-G2 壁厚600mm女川原子力建屋建築研究所新館
Natural freq. Mass
Stiffness
Rat
io o
f nat
ural
freq
. (-)
Onagawa NPP
BRI bldg
Large shrinkage conc. (1100µ)
Small shrinkage conc. (800µ)
Thickness = 600 mm Large shrinkage conc. (1100µ)
- Order of reduction of natural frequency is reproduced. - Finishing coarting, detailed environmental conditions are not considered. A. Sugie, I. Maruyama, M. Teshigawara, 21588 Numerical simulation for stiffness change of RC wall due to drying, Summaries of technical papers of annual meeting, 2014 (2014) 1175-1176.
Ippei MARUYAMA, NAGOYA UNIV.
CONCLUSION : MULTI-SCALE MODELLING - Even we use a cascaded scale modeling, final mesh size
of numerical analysis should be comparable to the governing phenomenon of target physical property. It is important to understand the key scale which control the target phenomena.
- There are multi-scale cracking, we need multi-scale modeling of cracking. Minor cracks is considered implicitly as reduction of Young’s modulus in the present study.
- The modeling needs scientific background, not the experimental background for extraporating. We should collect scientific knowledge as possible as we can.
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Ippei MARUYAMA, NAGOYA UNIV.
WE NEED ACTUAL PERFORMANCE - Knowledge for design is not the same as that for aging
management, because we can not evaluate actual performance of concrete structure. Even it is beyond required performance, we need it.
- Numerical and experimental investigations for both actual performance and aging behavior are strongly needed.
- Multi-scale vision and insight for understanding the concrete structure should be enhanced by proposing working hypothesis through multi-scale modeling.
- Experiment from a view point of modelling and experiment to find something new are needed.
- Collaboration between numerical modeler and experimental investigator is the key for future research.
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Ippei MARUYAMA, NAGOYA UNIV.
Thank you for your kind attention
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