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A RATIONAL METHOD FOR RCC DESIGNLuis Eloy Feo C. [email protected]
Caracas, Venezuela/ Ciudad de Panam, Panam
ABSTRACT. After years of experience using the RCC (Roller Compacted Concrete) in dam construction, a rational or logical method formixtures design has not been developed yet. Some experts, depending on the country of origin and their particular experiences, aim to asimilar approach on concrete design while others, to a lesser extent, have been placing the focus on soils. However, none of these are based
on a rational design method where the inputs, external variables controls, a standardized process and a predictable response corresponding to
mechanistic reasoning are clearly established. This shortcoming converts the design in a trial and errorprocess, leaving the production-placement control stage subject to decisions that sometimes are not oriented to meet the desired goals. In order to design, is requiredconsensus in some input elements, which exists at least in the case of the characteristics of the mixture components. The same cannot be said
about the compaction energy, where a standardization based on experience is necessary. Once these input elements are defined, it onlyremains to control the external variables that can affect the RCC production: handling lapses, temperature and relative moisture; and the
properties that have an influence in the functionality of geomaterials, being these the void ratios in the compacted mixture. The experiencesgained so far using RCC allows this approach.
INTRODUCTION
The handling of petrous material as inputs to civil
construction has lead to the comprehension of thevariables that govern the behavior and the expected
response from the processed material, namelyconventional concrete, asphalt, cement-bentonite,
filling soils and -the case of study of this paper- theRCC. All of these materials have in common the fact
that the main input is an aggregate of mineral origin,
so the differences are related to the binding agentused. These materials are best known as
geomaterials.
For instance, the improvement of the Marshall essay
for the design of asphalt mixtures required years of
practical experiencing and laboratory tests, to reach aconsensus regarding which void properties satisfy the
functionality of the asphalts in terms of workability,durability and mechanical response.
At the beginning of this century, people tried to
migrate from Marshall essay to the Superpave
evaluation, nevertheless in both cases the three mainproperties defining the asphalt response in terms of
workability and durability are the void ratios
remaining after the compaction of the mixtures: totalvoids in mix or trapped air (Vt), filled void (%VF) and
voids of mineral aggregates (VMA).
In order to ensure these variables, and considering
that the energy of confection of the briquettes isstandardized, the amount of binding agent is
determined as a dependant variable.
In this case, the binding agent is asphaltic liquid,
which has very stable properties. This means themeasurable mechanical properties (stability and
flow) are only verified at the end of the design
process. Nevertheless in the case of RCC thprinciple is still the same, some addition
considerations must be taken into account.
After more than 30 years using the RCC for da
construction, it is understood that the capacity of tmaterial to be handled is as important as t
compression resistance, and above any consideratio
the capacity to guarantee the interlayer union durinthe placement stage. So, assuming consensus in t
components characteristics and a specific energy f
the construction of tests specimens, the function
characteristics should be governed by the amount binding and the mechanical response associated
the quality of it, defining the binding as the pas
containing all the fine particles that migrate durin
the process of compaction and fill the void spaces, described in the diagram at Figure 01.
For the first case, functional requirements, addition
research works and the successful experiences usinRCC must be noted, in order to establish the range
variation of the variables already mentioned: tot
void (Vt), filled void (%VF) and mineral aggregavoid (VMA).
In the second case, determining the quality of t
paste, it is used the known proportion between t
compressive strength and the ratio a: (c+pconsidering into the cementitious material t
properties of mineral supplements (p), sometim
required in the RCC to meet other properties such alkali-aggregate reaction, heat of hydratio
production costs, or even the need to increase th
paste volume for functional purposes.
This way, knowing the amount of paste and quality by functional and mechanical requiremen
both solutions are combined to obtain a theoretic
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design that allows starting a test program leading to
the optimal mixture, noting that this only depends onlocal variables and economic considerations.
Vt= Total voids ortrapped voids in the
mix.
VMA= Voids in the
Mineral Aggregate.
%VF= Voids Filled =
VP/VMA
VM; MM= Volume andMass of Mineral
Vp; Mp= Volume andMass of Paste
Vassd; Massd= Volume
and Mass of Aggregates,Saturated-Surface-Dry
(Including Filler)
Vc; Mc= Volume andMass of Cement.
Vw; Mw= Volume andMass of Free-Water
Va; Ma= Volume andMass of Additive
Vf; Mf= Volume and
Mass of Mineral
Supplement.
V#200; M#200= Volume
and Mass of Passing
#200
Total Mass
Total VolumeGi= Specific Mass for
each component= Mi/Vi
GSSD= Specific Mass of
Aggregates Compounds
(Saturated-Surface-Dry)
Figure 01, Phase diagram for RCC
Although this article does not expand on the subject,
for this approach it is necessary to control external
variables that affect production and the end result of
a mixture of RCC. These variables are the maximumtime that the mixture can be worked once
components are combined, the relative moisture andthe temperature at which the design mixtures aremade.
MATERIALS PROPERTIES
The minimum characteristics that the RCC
constituent materials should have, are very similar tothose known for other geomaterials. The convention
is to use the specifications (ASTM or other) that
apply to conventional concrete, with some exceptio
and in some cases with more flexibility. In thsection, we only will refer to these exceptions
other relevant issues.
Cement: Some countries have abandoned t
production of cement according to ASTM C-15which classifies the cements according to the
chemical composition. Based on environment
requirements, some companies in some countrihave adopted the manufacturing pattern based
ASTM-C1157, that take into account t
performance parameters instead of the chemic
composition of cement. In either case, the cement be used for the manufacture of RCC should be low
alkali content, less than 1%. Additionally, the heat
hydration must be low.
Aggregates Quality: Although the specifications fselection of aggregates for RCC production tend
be more flexible than those applied for tconventional concrete, in general terms the durabilishould be guaranteed against chemical an
atmospheric agents, as well as minimum mechanic
resistance in order to avoid excess breakdown durinhandling, mixing and placement.
The most important exception in the selection
aggregates relates to the potential reactivity tes
between the cement and alkalis. The variostandardized tests to evaluate this parameter ha
two extremes: either they are very slow to gi
reliable results or are severe, with tendencies disqualify many potential sources of aggregates.
this regard it must be remembered that the doses
cement in RCC are much lower than those used
conventional concrete, so a critical judgment required when deciding the applicability of the
standards. The recommendation is to ma
adjustments to these tests for RCC designconsidering in each case the actual workin
conditions of the mixture.
Fine particles: There are RCC design specificatiowith plastic fines up to 6%, unacceptable values fconventional concrete. At this point the design
must make a judicious balance of additional cos
associated to the increase in the cement amount this usually related to the use of plastic fines in th
mix.
The same happens to non plastic fines, where the
are no limits in the amount of fines included in RC
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mixtures, the opposite case to the conventional
concrete mixture.
GRADING CURVE
The selection of the gradation to be used on the
design process must meet the following criteria: 1)
minimize the stockpiles of component materials; 2)the combined mixture of RCC must guarantee the
consistency in every stage of production, storage and
handling and also should be considered the way of
supply: by truck or by conveyor belt; 3) The mixturemust meet the higher density and the lower void
amount; 4) It is recommended to use the biggest size
available, taking into account that as the higher themaximum size (NMSA), the bigger the tendency to
segregate.
The design manual USACE (Ref. 11) recommends
the use of ideal combinations for the stockpiles ofcoarse aggregates, fine aggregates and combined
aggregates.
On the other hand, Brazilians used as typical curve
for combined aggregates, the following expression:
%Ppasante= (d/NMSA)1/3
x 1005%
with NMSA, maximum particle sizebetween 50 - 60 mm
d, sieve size.
COMPACTION ENERGY
There are several ways of making RCC testspecimens for laboratory testing. Of these, only two
are standardized: using the vibrating hammer (ASTM
C1435) and the vibrating table (ASTM C1176). Forboth tests there is not an energy pattern that unifies
them.
This energy cannot be a random selection, as it
should be a mirror of the energy used in-field, andthe nature of this depends only on the equipment
used for compaction. It is also widely known thatexcess energy in compaction of geomaterials iscounterproductive, as it can lead to material fatigue.
For instance, the energy associated to Modified
Proctor test (ASTM D1557), is known as a
successful energy to achieve adequate levels of soilcompaction and it is characterized by a value of
2.700 kN-m/m3, or in terms of mass 275.510 5.900
kg-m/m3. In the case of preparation of Marshall testspecimens (ASTM D2926 and ASTM D5581), the
energy varies from a minimum of 403.200 kg-m/m
for low traffic roads up to 605.000 kg-m/m3 frailway medium-high traffic.
For now, and in the absence of data that allows us
discriminate other energy levels for different types
RCC mixtures, we recommend setting the energy fthe construction of test specimens to a lev
equivalent to the Modified Proctor, i.e. 275.510
5.900 kg-m/m3.
The energy setting for each type of instrument usto make specimens requires knowledge of the ma
frequency and amplitude of impacts. For examp
the Tamper-06 Jet Toku (www.tamcotools.comwith a mass of 18 kg, has an impact rate of 60
strokes / min and an amplitude of impact equal to
"(140 mm). It would require 20 sec compaction b
each of the 3 layers forming a cylinder with diameter of 15 cm and height of 30 cm:
AMOUNT OF PASTE
The void properties that govern the behavior of RC
are shown below. The values used to set the rang
of variation were based on a review of variospecifications for projects, the exchange
information with experts and laboratory testing in th
scope of this work. It is necessary to conduct an hoc research to review and adapt these values.
Total voids (trapped air) in mix (Vt):
A high content of voids decreases density, increas
permeability and as a consequence, decreases t
durability of the compacted RCC. In the case of RCthere is not a functional limitation for the minimu
level of voids, so the limit is constituted by th
physical barrier representing the saturation curvwhich depends only on the particle shape and si
distribution. The maximum allowable air voids ratis set to 4%, a value that can be reached wi
conventional energy levels used in - field and abovwhich, the RCC guarantee their mechanic
properties, while the minimum level is set at 1
since it is a value achievable in laboratory with thselected energy level, corresponding
approximately 275.510 kg-m/m3.
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Voids of mineral aggregate ratio (VMA):
The compacted mixture needs to have enough
intergranular space to contain the paste, guaranteeingthat all particles are coated. The volume of paste
(Mp, Vp in Figure 01) must be sufficient to ensure
not only the coating but also the effective bondingbetween layers. However, the amount of paste cannot
be exceeded because it reduces the workability of the
mixture, increasing the amount of adhered materialinside trucks and compaction equipment, causing
operational problems.
In the first years of experience in design of mixtures
with the RCC, this variable (VMA) was between 18%and 20%, although designs are reported with ranges
as high as 28% (Ref. 10). The trend in the design of
RCC mixtures in recent years has been restricting
this variable to a range between 22 and 24%.
Filled voids ratio (%VF):
This parameter, at least for high traffic asphalt is
used to limit the maximum VMA value. Because the
RCC does not have this restriction, with experimentaldata to constrain this variable and for the purposes of
this study, limits are set outside the range of
influence, which is determined by the above
parameters (see Equation 10).
The determination of the optimal volume of paste
(Mp and Vp) which guarantees the void properties
(Vt, %VF and VMA), has a mathematical solution for
the asphalt case (Ref. 08). Based on this, somevariations can be done to model the RCC case.
Definitions (see Figure 01):
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(
(
(1
After combining and grouping these equations, thr
functions result, based on unit weight Uw=f(Pp):
(
(
(
If each of this functions is represented in the pla
Uw Pp for limit values of void ratios (%Vt, %
and %VMA), it can be obtained, assuming hypothetical RCC with Gp=1,86 kg/m
3and GM= 2,
kg/m3, the Figure 02.
The optimal amount of paste and the density
RCC that satisfy the void ratios is the centroid of thresulting polygon. To assure this, there are up to
nine possible combinations based on the 10 verticderived from Figure 03, with the conditions shown Table 01.
Then, the determination of each vertex is made wi
the equations 11 to 16, evaluated in the limit valu
of the void ratios (%Vt, %VFand %VMA).
Figure 02, Polygon of voids
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Figure 03, vertices of polyvoid (see Ref. 08)
# Querya I II III IV V VI VII VIII IX
1 Uw5>Uw1 x x x
2 Uw2>Uw6 x x x x x x
3 Uw7>Uw3 x x x X x x
4 Uw8>Uw4 x x x X x x
Vertices thatmake the
polygon
1,2,9,7,4
5,2,9,7,4,1
0
5,6,7,4,10
5,2,3,8
5,6,7,8
5,2,9,7,8
5,2,3,4,10
1,6,7,4
1,2,3,4
Table 01 (see Ref. 08)
Pp Ec.# Uw
(14)(12)
(13)
(15)(11)
(12)
(16)
(11)
(13)
Finally, these definitions derived from the Figure 01are introduced:
(17)
(18)
(19)
The specific weight for compound materials
obtained by using the following generic formula:
(2
From which can be obtained the specific gravity
the paste (GP) and the mineral fraction (GM):
(2
with X= initial assumed proportions.
(2
For the particular case where the design is nrestricted by the filled voids ratio (%VF), and with established range for VMA (between 22 and 24%) an
Vt (between 1% and 4%), exists only one solution f
the optimal paste percentage and the density th
satisfies the void specification
(2
(2
PASTE QUALITY
To determine the quality of the paste that guarantthe expected mechanical properties of the mixture,
is used the known correlation between ratio =a/
and the compression resistance.
The guide 207.5R.11 published by ACI (Ref. 0
offers a general ratio for RCC mixtures with Vetime below 45 seconds (See Figure 04).
Although this guide does not specify details about th
degree of compaction of the test specime
considered, it makes reference to the standard ASTC1435 (about construction of test specimens), so w
assume this relation (Figure 04) is valid for the vo
parameters established in this paper.
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Figure 04 (from Ref. 01)
Additionally, we use as a reference the parameters
listed in the document ACI 214R-02 (Ref. 02) todetermine the maximizing factors of the design
resistance against the nominal resistance, consideringthe dispersion of the results in terms of the qualitycontrol and the allowable fraction defective, adopting
the criteria defined in Table 02 and affecting the
design resistance according to Equation 25.
(25)
where:
Fcr Design resistancefc Nominal resistance
V Coefficient of Variation (Table 02)
Z Typified variable of the normal distribution for thepermitted fraction defective according Table 03
Quality control Coefficient of variation (V)
Excellent 5%
Very good 10%
Good 15%
Fair 20%
Poor 25%
Table 02, Coefficient of variation for the expected
quality control
Quantil or Defective Fraction Z
2% 2,054
5% 1,645
9% 1,340
10% 1,282
15% 1,036
20% 0,842
Table 03, Variable z for established quantiles
correction
For different aggregates to those considered in Figu04, it is recommended to adjust the value obtained b
using =w/c, with those factors shown in Table 0and 05.
Max. Size (NMSA) 1 2 2 3
KRFactor 1,15 1,1 1,05 1
Table 04, KRFactor for NMSA correction
Crushed
from
quarries
Semi-
crushed
Natural grav
or boulders
Crushed sand 1 0,97 0,95
Natural sand 0,97 0,95 0,93
Table 05, factor KAfor type of aggregate
Correction due to the type of cement
The curves in Figure 04 are values obtained for
Type II Cement, ASTM C150.
The use of different cements involves an adjustmeconsidering the proportional relation betwe
concrete resistances as a function of the cemen
resistance, measured in normalized mortaaccording the ASTM C109/C109M.
(
Where:
q Adjustment factor of curves, Figure 04
Rgrout cement Strength of grout cement at 3 or 7 days (Mp
Rgrout type II Strength of grout cement Type II, ASTC150, as follow:
10 Mpa at 3 days/ 17 Mpa at 7 days
Coarse
Fine
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Correction due to plastic fines or pozzolanic activity of
non-plastic fines
Sometimes it is not possible to avoid the presence ofplastic fines in the aggregates, causing an additional water
demand and therefore the need to increase the amount ofcement. This amount is increased proportionally to thepercentage of fines passing the sieve # 200 and the plastic
index (Ip) of these, up to a maximum value of Ip = 25.
Also, it is considered that the presence of non-plastic fineswith pozzolanic activity can decrease the demand forcement. In this case, the decrease is proportional to thepozzolanic index of the combination of all the fines
present in the aggregates including, if applicable, themineral supplement used. This Pozzolanic Activity Index(PAI), should be determined according to ASTM C311and affected by an empiric factor, which, within the scope
of this paper, is = 0,50.
CALCULATION PROCESS
Currently the company is participating in the design of theRCC mixture for the dam Cuira, located in MirandaState, Venezuela. This dam will have a height of 135 m
and an estimated volume of RCC close to 1MM m3. Thefollowing sequence, describes the design process usingthe experimental data and results obtained to date withone of the available aggregate sources, taken from thecrushing of rocks characterized as metavolcanicdetritic-
lithic sandstones (metatuffs).
Step 1, Combination of aggregates: The aggregates aregrouped in stockpiles characterized with the specific
gravities and grain sizes shown in Table 06.
Step 2 Design Strength: To check against the availableresults, the mixture is analyzed at 28 days, with anaverage value of 6,95 MPa expected.
Assuming a defective fraction of 10% and a qualitycontrol "Outstanding", the following results are obtained
from Tables 02 and 03:
V, Coefficient of Variation = 10% Z, Standardized Variable = 1,282
Fcr= 7,43 Mpa (Equation 26)
Step 3, Water / Cementitious Material ratio: A designstrength ofFcr= 7,43 MPa, is entered in Figure 04 (curvecorresponding to 28 days) to obtain an initial value of thewater / cementitious material:
calculus= (4,1202/7,43)^(1/1,724)= 0,711
Step 4, Adjustments to water / cementitious material: The
result obtained from the previous step must be adjustedaccording to the characteristics of the aggregates, finesproperties and cement.
Aggrega-
tes
Specific
Gravity
(SSD;
kg/m3)
Grain Size
(%passing)
% Combined
Grain Size
(% passing)
Gravel 1 2.725 (d/22,3mm)^0,86
(R2=0,962)
25 (d/37,9 mm)^
(R2= 0,991)
Passing #200
7,84%
Moisture:1,92
Gravel 2 2.775 (d/37,7mm)^2,71
(R2=0,994)
27
CrushedSand
2.737 (d/5,6mm)0,48
(R2=0992)48
d: sieve opening size;R : Coefficient of the curve fitting.
Table 06, composition of Cuira RCC mixture
Step 4.1, Aggregates:
Maximum size of Aggregate (NMSA): 2 ", of Table 0KR= 1,1
Crushed Aggregates: Table 05 KA= 1
Step 4.2, Fines Properties: The combined aggregate have7,84% of non-plastic fines (rock dust) with a Pozzolan
Activity Index (PAI) of 62%.
In order to estimate the amount of fines in the final mixtu
is necessary to have a first estimate of the composition the mixture based on an assumed percentage of paste anthe water / cementitious materialratio specified in step 3.
With an assumed percentage of paste Pp = 18% andcalculated = 0,711; a preliminary dose is calculated usithe following equations derived from Figure 01 (letters P V, equations 27 to 33, are auxiliary variables):
E
(2
Note: %Abs.: weighted absorption of aggregates
(2
(2
(2
(3
(3
(3
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(33)
(34)
(35)
(36)
(37)
(38)
(39)
So, the non plastic fines represent an amount of equivalentcement that can be determined as follows:
Adjust for equivalent cement: PAI x Passing#200_1 x
= 0,62 x 176,24 x 0,50= 54,64 kg
Step 4.3, Cement Properties: A Type II Cement is used(ASTM C150), resulting in a KC=1.
Finally, the water / cementitious materialratio is adjustedas follows:
adjusted= (Estimated_Water_1/(Estimated_Cement_1-Equivalent_Cement))*Kr*Ka*Kc = 118,1/(166,2-54,64)*1.1*1*1 = 1,164
Paso 5, Recalculation of doses::The doses of cement, waterand aggregates are recalculated using the same equations
than Step 4.2 but with adjusted.
Estimated_Cement_2 (kg) 128,3
Estimated_Water_2 (kg) 149,4
Aggregate_Volume_2 (lt) 809,9
Aggregate_Mass_2 (kg) 2.222
Passing #200_2 (kg) 172,2
Filler_2 (kg) 0
Below, the following parameters are determined:
Equation 18:TMD= 149,4 kgwater/m
3 + 128,3 kgcement/m3 + 2.222
kgaggregates/m3= 2.499,7 kg/m3
Equation 21:
Equation 22:
Step 6, Determination of the optimal percentage of pasWith the void specifications shown in Table 07, the resuobtained in Step 5 (GP' and GM') and Equations 11 to 1the 10 vertices from Figure 03 can be determined. STable 08.
Trapped voidsin mixture, Vt
(%)
Voids in MineralAggregate VMA
(%)
Void filledwith paste
VF(%)
Minimum 1% 22% 81,8%
Maximum 4% 24% 95,8%
Table 07, Voids specifications for Cuira RCC
Pp Uw
Equation
14
14,2% 2.437
16,2% 2.496
14,8% 2.518
12,9% 2.463
Equation
15
14,4% 2.444
16,2% 2.496
14,7% 2.516
12,9% 2.463
Equation
16
12,9% 2.463
16,2% 2.496
Table 08, Polivoid, first iteration Cuira design
With this, it can be verified that the Case V (Table 01)
satisfied; resulting the voids polygon as a figure formed vertices 5, 6, 7 and 8. The centroid of the polygon is thaverage of its vertices, from which can be calculated:
%Pastecalculated: 14,57% and Uw: 2.480 kg/m3
As the Filled Void (Vf) specifications does not restrict tdesign, the result can be verified by using equations 23 a24.
Step 7, Iteration: Repeat the process from Step 4.2 un%PasteAssumed=% Pastecalculated.
By performing several iterations with a spreadshe
(available to the reader via e-mail at [email protected] %Paste converges to 14,73%; while the obtaindosage corresponds to the indicated in Table 09, where apresented the proportions used in the actual design and tresults obtained at compression 28 days later. This desi
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was not tested in the equipment VeBe but we can confirmthat the preparation of the samples was successful,obtaining an adequate interlayer binding.
It was also verified others RCC designs for different source
of aggregates, including those within the scope of thiswork, other known successful design and even designsavailable in the literature (Ref. 10).
Dose forCalculation Real Dose
(by m3)
Gravel 1 (SSD) 588,67 Kg 587,62 Kg
Gravel 2 (SSD) 635,76 Kg 634,63 Kg
Crauhed Sand (SSD) 1.130,25 Kg 1.128,24 Kg
Water 117,75 Kg 117,29 Kg
Cement 75,03 Kg 80,00 Kg
a/c 1,569 1,466
Average Resistance(Mpa) Prediction Real
28 days 7,43 7,4390 days 14,13 10,23
180 days 17,18 Pending
28 days 20,23 Pending
Table 09, Cuira RCC design by calculation vs real dose
The prediction in all designs was quite tight. However, theexperimental nature of the proposed method warrants thatthe results obtained are considered only as a reference tostart a testing program that will lead to the final design.
According to our experience, the optimal values of
moisture tend to be in the range of (+1% to +1.5%) pointsabove the optimal moisture of the combined aggregates(without cement) taken from the Modified Proctor test(ASTM D1557), therefore a final testing program can fit
into an array of pre-designs considering this range ofmoisture.
Note: When dosing, an adjustment that considers theactual moisture of the aggregates should be done.
QUALITY CONTROL
One of the advantages of the design method proposed is toprovide rational references for the quality control of theRCC.
This control should aim to ensure both parameters of the
mixture produced, expressed in quantity and quality ofpaste, as well as specified void parameters, being these
directly dependent on the placement. The production of amixture similar to that established in the design isguaranteed by meeting these three parameters
simultaneously.
Production Control
A previous definition of the lots to control is required (volume or frequency). After this, it is necessary measure the following parameters in the RCC mixture.
Theoretical Maximum Density (TMD): In this regarthe ASTM D2041 can be used. Alternatively it can used the DMA Brazilian test (Ref. 03), which simpler but less accurate.
As a reference, it has been observed that the TMD an asphalt mixture for airport runways (Ref. 04) in
plant with a rigorous quality control reached maximudifferences of 30 kg/m3 inter-daily and 70 kg/m3 intweekly even with aggregates from quarries. Th
variation would be much greater if the aggregates wederived from sedimentary sources.
Percentage of Paste, Pp: Represents all the material thpasses through the sieve #200. It is recommended use the ASTM C117.
Specific Gravity of Mineral (GM), in Saturated-SurfacDry (SSD): it corresponds to all the material retainby the sieve #200. It is recommended to use the ASTC127.
By measuring these parameters, the specific gravity of tpaste (GP) in SSD condition can be calculated. This allow
control of the composition and therefore the quality of tpaste:
(4
Also, for each lot, samples must be taken in order prepare the test specimens for further tests of resistancKnowing the GM and GP and the true density of the tesspecimens, the Void Properties can be determined (s
Equations 41 to 44). The actual density can be obtainby dividing the mass of the specimen by its volumdetermined this by the actual dimensions measured withprecision of three decimal places. This alternaticalculation based on real measurements, it is easier
voids determination according to ASTM C231.
Placement Control:Control of the placed material is performed by measurinthe density at site (Uw) with a Nuclear Densimeter (ND
to obtain the following relationships:
(4
(42
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(43)
(44)
=(10)
Nevertheless, it should be advised that the ND might notbe so accurate in order to measure real density to qualitycontrol purposes under this scope. In that case core drilledshould be taken after a period later than setting and
hardening time, usually more than 3 days, leaving the useof the ND only for the placement control stage.
CONCLUSIONS
A design method combining the accumulated experiences
in the use of RCC with design and quality control ofasphaltic mixtures is proposed.
The basic approach is to get a suitable amount of paste
that ensures an effective interlayer bonding. The knownexperience, as well as the actual trend, suggests thatvariable Voids of Mineral Aggregate Ratio (VMA)should be limited in a range between 22-24%. However, it
is necessary to have more experimental evidence toconclude on the relationship between VeBe time and
VMA specification.
The method offers an accurate prediction of themechanical response of the mixture, based on thestandardization of the energy used for the confection of
tests specimens and uniformed properties of components.
In addition, to better the goal of prediction, it was takeninto account the fines characteristics, ranging fromplastic fines to non-plastic fines with puzolanic activity.
This prediction allows closing the whole spectrum ofpossible combinations, representing an appropriatestarting point in a testing program or a reference in theeconomic evaluation of a mixture of RCC.
The alternative variable to define a pre-designs matrix isthe optimal moisture of the aggregates, obtainedexperimentally before combining them with cement. This
is because the final moisture of the RCC mixtures tends tobe in a range between +1 and +1,5% points above the
optimum water content of the ASTM D1557, measured onthe aggregates without cement.
Another advantage offered by the proposed method is the
rationalization of the quality control, as the design basedon voids specifications minimizes the disputes oftenobserved in field between Contractor and Inspector.
The worksheets needed for the design, dosage and qualicontrol, as well as all the detailed information in rega
with this investigation, can be requested to [email protected].
REFERENCES[01] American Concrete Institute (2012) ACI 207.5R-11 Report
Roller-Compacted Mass Concrete. USA.
[02] American Concrete Institute (2002) ACI 214.R-02 Evaluationstrength test result of concrete. USA.
[03] Andrade, M.A.S.; Pimenta, M.A., Bittencourt, R.M.; FonseA.C.; Fontoura, J.T.F y Andrade, W.P..(2003) DMA, a simpdevice for measuring unit water in RCC mixtures. ProceedingsFourth International Symposium on Roller Compacted Concr
(RCC) Dams, 17- 19 November 2003, Madrid, Spain.[04] Ingeniera Geotcnica Prego (2008-2010) Informes de control
calidad para la construccin de pistas del Aeropuerto Jos AntonAnzotegui. Trabajos contratados con Consorcio Wydoca p
PDVSA. Edo. Anzotegui, Venezuela.[05] Lamont, J.F y Pielert, J.H.(2006) Significance of test a
properties of concrete and concrete-making materials. ASTInternational standard worldwide, STP 169D. Bridgeport, NJ, US
[06] Lpez, J.E.; Schrader, E. y Gackel, L. (2012) RCC D
construction conveyors or trucks. Proceedings of SiInternational Symposium on Roller Compacted Concrete (RCDams, 23- 25 Octuber 2012, Zaragoza, Spain.
[07] Porrero S., J; Ramos R., C; Grases G., Jos y Velazco G.J. (20Manual del Concreto Estructural, conforme con la Nomra Cove1753-03. SIDETUR, Venezuela.
[08] Snchez-Leal, F. (2010) Manual Digital Seminario Suelos
Mezclas Asflticas RAMCODES, Supertraining RAMCODES 20Barquisimeto, Venezuela.
[09] Snchez-Leal, F., Garnica, P., Gmez, J. y Prez, N. (200RAMCODES: Metodologia Racional para el Analisis Densificacion y Resistencia de Geomateriales Compactad
Publicacin Tcnica N 200, Instituto Mexicano del TranspoIMT. Quertaro, Mxico.
[10] Rizzo, P; Osterle, J.; Schrader, E. y Gackel, L. (2003) Saluda D
mix design program. Proceedings of Fourth InternatioSymposium on Roller Compacted Concrete (RCC) Dams, 17-
November 2003, Madrid, Spain.[11] US Army Corp of Engineers (2000) EM-1110-2-2006 Rol
Compacted Concrete. Manual of Engineering and Design 1January 2000.
8/13/2019 Rational Method for RCC Design-ML
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Attachment 1
Date: Sept., 2013 Design: 002
3 4 22.6
z= 1.282 5%
6.95 Actual Fcr
to 7.43 Mpa
28 DAYS
Voids in mineral
aggregates, VMA(%)
Range for Voids filled
with paste, VF(%)
Voids filled with paste, VF
(%)
22.0% 81.8% 81.8%
24.0% 95.8% 95.8%
Kc 1.00 KR 1.10 KA 1.00
Label Type
Specific gravity (SSD,
ton/m3) % Abs. Proportion (%)
Actual doses
(kg)
Gravel 1 Crushed gravel 2.713 1.19% 25.0% 587.62 Kg
Gravel 2 Crushed gravel 2.766 1.24% 27.0% 634.63 Kg
Sand 1 Crushed sand 2.746 1.10% 48.0% 1128.24 Kg
Sand 2 2.5 Filler/Cement ratio
Filler 2.5 0%
GSSD: 2.743 ton/m3 1.16% 100%Specific gravity
(ton/m3)
1.569 Water_adjusted 1 117.29 kg
1.569 Cement_adjusted 3.15 80.0 kg0.457 Admixture 1.5 0.00 kg
Volume_agreggate: 858.4 lt Passing #200 182.5 kg 182.2 kg
Mass_aggregate: 2354.7 kg Paste (mass) 375.3 kg 379.4 kg
2547.5 kg/m3 Calculed Paste (%) 14.73% 14.89%
%Paste_min 14% 20%
Cont. Camargo-Correa
Cuira, DAM, M iranda State, Venezuela
V=
Setting cementiuos material (Kg):
Type ofcontrol:
Design strength, Fcr (Mpa):
Total voids, Vt (%)
1%
4%
DESIGN OF ROLLER COMPACTED CONCRETE (RCC)
Code of record:
Project:
Contract:
Customer:
%Paste_max
Test age of grout
Comp. Str. (Mpa) of grout, used
cement
Range for % Paste
7.43
Voids specifications
0.711
14.71%
14.73%Assumed Paste (%)
Calculated Paste
(%)
Characteristics of fines
Passing #200
2.65
Aggregate combination (after compliance with specified band)
Assumed Str. grout
ratio
Final ratio w/c:
% Defective fraction:
Minimum
Maximum
Specific gravity of P.
#200 (ton/m3)
Initial Water-
Cementious ratio for
design:
7.84% Liquid limit
0.5
Choose the following parameters
Strength (Mpa)
62%
Final Str. grout ratio
2 Inch
Choose NMSA
58.06
Water-Cementious ratio adjusted:
Plastic index
Characteristics of cement (grout tested as ASTM C 109/C109M)
Final ratio w/(c+p+passing #200):
Cement type Type II, Astm C150
Adjusment to water-cementitious ratio
Theoretical Maximum Density (TMD):
1.569
12.00 1.00
3 DAYS
Final ratio w/(c+p):
Pozzolanic activity
index
8/13/2019 Rational Method for RCC Design-ML
12/15
Attachment 2
Date: 2001 Design: 004
7 4 Enter value for Fcr (Mpa): Actual Fcr
19.75 Kg
z= It will be used Fcr value It will be used Fcr value
19.75
to
1 YEAR
Voids in mineral
aggregates, VMA(%)
Range for Voids filled
with paste, VF(%)
Voids filled with paste, VF
(%)
28.0% 85.7% 85.7%
29.0% 96.6% 96.6%
Kc 1.00 KR 1.15 KA 1.00
Label Type
Specific gravity (SSD,
ton/m3) % Abs. Proportion (%)
Actual doses
(kg)
Gravel 1 Crushed gravel 2.681 2.00% 49.8% 1070.54 KgGravel 2 2.766
Sand 1 Crushed sand 2.746 2.00% 46.0% 988.19 Kg
Sand 2 2.6 Filler/Cement ratio
Filler Pozzolan 1.5 1.0% 4.2% 122% 89.07 Kg
GSSD: 2.623 ton/m3 1.96% 100%Specific gravity
(ton/m3)
2.005 Water_adjusted 1 149.64 kg
0.903 Cement_adjusted 3.15 74.2 kg0.613 Admixture 1
Volume_agreggate: 826.6 lt Passing #200 78.7 kg 77.9 kg
Mass_aggregate: 2168.0 kg Paste (mass) 394.1 kg 390.9 kg
2392.4 kg/m3 Calculed Paste (%) 16.47% 16.48%
%Paste_min 16% 23%
Theoretical Maximum Density (TMD):
2.005
12.00 1.00
3 DAYS
Final ratio w/(c+p):
Pozzolanic activity
index
Characteristics of cement (grout tested as ASTM C 109/C109M)
Final ratio w/(c+p+passing #200):
Cement type Type II, Astm C150
Adjusment to water-cementitious ratio
Choose the following parameters
Strength (Mpa)
90%
Final Str. grout ratio
1 1/2 Inch
Choose NMSA
79.40
Water-Cementious ratio adjusted:
Plastic index
% Defective fraction:
Minimum
Maximum
Specific gravity of P.
#200 (ton/m3)
Initial Water-
Cementious ratio for
design:
3.70% Liquid limit
0.5
16.40%Assumed Paste (%)
Calculated Paste
(%)
Characteristics of fines
Passing #200
2.50
Aggregate combination (after compliance with specified band)
Assumed Str. grout
ratio
Final ratio w/c:
19.75
Voids specifications
0.722
16.47%
DESIGN OF ROLLER COMPACTED CONCRETE (RCC)
Code of record:
Project:
Contract:
Customer:
%Paste_max
Test age of grout
Comp. Str. (Mpa) of grout, used
cement
Primary Mix, 125+150
Range for % Paste
Saluda DAM, Columbia, USA
V=
Setting cementiuos material (Kg):
Type ofcontrol:
Design strength, Fcr (Mpa):
Total voids, Vt (%)
1%
4%
8/13/2019 Rational Method for RCC Design-ML
13/15
Attachment 3
Date: 2001 Design: 003
7 4 Enter value for Fcr (Mpa): Actual Fcr
23.34 Kg
z= It will be used Fcr value It will be used Fcr value
23.34
to
1 YEAR
Voids in mineral
aggregates, VMA(%)
Range for Voids filled
with paste, VF(%)
Voids filled with paste, VF
(%)
28.8% 86.1% 86.1%
29.8% 96.6% 96.6%
Kc 1.00 KR 1.15 KA 1.00
Label Type
Specific gravity (SSD,
ton/m3) % Abs. Proportion (%)
Actual doses
(kg)
Gravel 1 Crushed gravel 2.681 2.00% 49.8% 1056.96 KgGravel 2 2.766
Sand 1 Crushed sand 2.746 2.00% 46.0% 975.65 Kg
Sand 2 2.6 Filler/Cement ratio
Filler Pozzolan 1.5 1.0% 4.2% 94% 89.07 Kg
GSSD: 2.623 ton/m3 1.96% 100%Specific gravity
(ton/m3)
1.568 Water_adjusted 1 153.80 kg
0.808 Cement_adjusted 3.15 89.1 kg0.557 Admixture 1.5
Volume_agreggate: 819.0 lt Passing #200 84.1 kg 83.0 kg
Mass_aggregate: 2148.1 kg Paste (mass) 420.8 kg 415.0 kg
2394.6 kg/m3 Calculed Paste (%) 17.57% 17.55%
%Paste_min 17% 23%
Theoretical Maximum Density (TMD):
1.568
12.00 1.00
3 DAYS
Final ratio w/(c+p):
Pozzolanic activity
index
Characteristics of cement (grout tested as ASTM C 109/C109M)
Final ratio w/(c+p+passing #200):
Cement type Type II, Astm C150
Adjusment to water-cementitious ratio
Choose the following parameters
Strength (Mpa)
90%
Final Str. grout ratio
1 1/2 Inch
Choose NMSA
81.40
Water-Cementious ratio adjusted:
Plastic index
% Defective fraction:
Minimum
Maximum
Specific gravity of P.
#200 (ton/m3)
Initial Water-
Cementious ratio for
design:
3.99% Liquid limit
0.5
17.50%Assumed Paste (%)
Calculated Paste
(%)
Characteristics of fines
Passing #200
2.50
Aggregate combination (after compliance with specified band)
Assumed Str. grout
ratio
Final ratio w/c:
23.34
Voids specifications
0.648
17.50%
DESIGN OF ROLLER COMPACTED CONCRETE (RCC)
Code of record:
Project:
Contract:
Customer:
%Paste_max
Test age of grout
Comp. Str. (Mpa) of grout, used
cement
Alternate II Mix, 150+150
Range for % Paste
Saluda DAM, Columbia, USA
V=
Setting cementiuos material (Kg):
Type ofcontrol:
Design strength, Fcr (Mpa):
Total voids, Vt (%)
1%
4%
8/13/2019 Rational Method for RCC Design-ML
14/15
Attachment 4
Date: Mar. 2007 Design: 002
3 3 22.6
z= 1.282 10%
9.85 Actual Fcr
to 11.30 Mpa
1 YEAR
Voids in mineral
aggregates, VMA(%)
Range for Voids filled
with paste, VF(%)
Voids filled with paste, VF
(%)
18.3% 72.7% 72.7%
19.3% 94.8% 94.8%
Kc 1.00 KR 1.05 KA 0.95
Label Type
Specific gravity (SSD,
ton/m3) % Abs. Proportion (%)
Actual doses
(kg)
Gravel 1 Semi crushed gravel 2.57 2.10% 32.0% 720.67 Kg
Gravel 2 Natural gravel 2.55 2.00% 23.0% 517.98 Kg
Sand 1 Crushed sand 2.56 1.71% 12.0% 270.25 Kg
Sand 2 Natural sand 2.54 2.00% 33.0% Filler/Cement ratio 743.19 Kg
Filler 2.5 0% 0.00 Kg
GSSD: 2.554 ton/m3 2.00% 100%Specific gravity
(ton/m3)
0.873 Water_adjusted 1 91.67 kg
0.873 Cement_adjusted 3.15 83.8 kg0.371 Admixture 1
Volume_agreggate: 887.7 lt Passing #200 127.6 kg 126.7 kg
Mass_aggregate: 2267.5 kg Paste (mass) 304.3 kg 302.3 kg
2444.1 kg/m3 Calculed Paste (%) 12.45% 12.45%
%Paste_min 10% 16%
Cont. Camargo-Correa
Guapo DAM, Miranda State, Venezuela
V=
Setting cementiuos material (Kg):
Type ofcontrol:
Design strength, Fcr (Mpa):
Total voids, Vt (%)
1%
5%
DESIGN OF ROLLER COMPACTED CONCRETE (RCC)
Code of record:
Project:
Contract:
Customer:
%Paste_max
Test age of grout
Comp. Str. (Mpa) of grout, used
cement
Range for % Paste
11.30
Voids specifications
1.032
12.46%
12.45%Assumed Paste (%)
Calculated Paste
(%)
Characteristics of fines
Passing #200 3%
2.54
Aggregate combination (after compliance with specified band)
Assumed Str. grout
ratio
Final ratio w/c:
% Defective fraction:
Minimum
Maximum
Specific gravity of P.
#200 (ton/m3)
Initial Water-
Cementious ratio for
design:
5.74% Liquid limit
0.5
Choose the following parameters
Strength (Mpa)
Final Str. grout ratio
2 1/2 Inch
Choose NMSA
-15.24
Water-Cementious ratio adjusted:
Plastic index
Pozzolanic activity
index
Characteristics of cement (grout tested as ASTM C 109/C109M)
Final ratio w/(c+p+passing #200):
Cement type Type II, Astm C150
Adjusment to water-cementitious ratio
Theoretical Maximum Density (TMD):
0.873
12.00 1.00
3 DAYS
Final ratio w/(c+p):
8/13/2019 Rational Method for RCC Design-ML
15/15
Attachment 5
Date: August, 2013 Design: Cuira 06
3 4 22.6
z= 1.282 5%
4.93 Actual Fcr
to 5.27 Mpa
28 DAYS
Voids in mineral
aggregates, VMA(%)
Range for Voids filled
with paste, VF(%)
Voids filled with paste, VF
(%)
16.6% 75.9% 75.9%
17.6% 94.3% 94.3%
Kc 1.00 KR 1.15 KA 0.95
Label Type
Specific gravity (SSD,
ton/m3) % Abs. Proportion (%)
Actual doses
(kg)
Gravel 1 Semi crushed gravel 2.754 1.40% 29.0% 690.03 Kg
Gravel 2 Semi crushed gravel 2.746 1.40% 27.0% 642.44 Kg
Sand 1 Natural sand 2.711 1.99% 44.0% 1046.94 Kg
Sand 2 2.5 Filler/Cement ratio
Filler 2.5 0%
GSSD: 2.733 ton/m3 1.66% 100%Specific gravity
(ton/m3)
1.196 Water_adjusted 1 103.22 kg
1.196 Cement_adjusted 3.15 80.0 kg0.704 Admixture 0.32 kg 1.5 0.32 kg
Volume_agreggate: 873.1 lt Passing #200 58.4 kg 58.3 kg
Mass_aggregate: 2385.9 kg Paste (mass) 242.6 kg 241.8 kg
2570.1 kg/m3 Calculed Paste (%) 9.44% 9.44%
%Paste_min 8% 14%
Final ratio w/(c+p):
Final ratio w/(c+p+passing #200):
Cement type Type II, Astm C150
Adjusment to water-cementitious ratio
Water-Cementious ratio adjusted:
Final ratio w/c:
Theoretical Maximum Density (TMD):
1.196
12.00 1.00
3 DAYS
70%
Final Str. grout ratio
1 1/2 Inch
Choose NMSA
20.66
Specific gravity of P.
#200 (ton/m3)
Initial Water-
Cementious ratio for
design:
2.49% Liquid limit
0.5
Strength (Mpa)
Plastic index
9.48%
9.44%Assumed Paste (%)
Calculated Paste
(%)
Passing #200
2.65
Aggregate combination (after compliance with specified band)
Range for % Paste
5.27
Voids specifications
0.867
Project:
Contract:
Customer:
%Paste_max
Test age of grout
Comp. Str. (Mpa) of grout, used
cement
Characteristics of fines
Assumed Str. grout
ratio
Pozzolanic activity
index
Characteristics of cement (grout tested as ASTM C 109/C109M)
Setting cementiuos material (Kg):
Type ofcontrol:
Design strength, Fcr (Mpa):
Total voids, Vt (%)
1%
4%
% Defective fraction:
Minimum
Maximum
Cont. Camargo-Correa
Cuira, DAM, M iranda State, Venezuela
V=
Choose the following parameters
DESIGN OF ROLLER COMPACTED CONCRETE (RCC)
Code of record: