New Progress on RollerCompacted Concrete Dams, Jia Jinsheng eta/. (eds)

@ 2007 China WaterPower Prees, ISBN 978-7-5084-4994-4'

Mixture Proportioning of Badovli RCC Dam

Hamidreza Araghian I, Kamran Qavami 2

1. Project Manager& Concrete Specialist, LAR Consulting Engineers, Tehran, IRAN. E-mail: hra@hra.ir2. Msc in hydraulic structures. E-mail: kqavami@yahoo.conl

Abstract: Badovli, a 98.8 meters high dam will be located in North West of IRAN, in West Azerbaijan province

near the Turkey borders on the Aghsu River.The project is Now under design and the main purpose ofconstruction of Badovli Dam is providing the potable water for Shoot,Bazorgan and Maku cities and water foragricultural purposes of Bazorgan and some part of Poldasht.This dam is located in 16 km far from Maku city &

216 km from Orumieh the capital city of West Azerbaijan porvince.The mean annual air temperature in thedam-site is 8.9 degrees of centigerade with minimum monthly average temperature of -3°C in the january.themaXilTIUm monthly average temperature is 19.4°C in July. Badovli is a roller compacted concrete dam with a totalvolume of 350,000 m3 (Ree volume is 290,000 m3

). For ensuring of the quality of the aggregates in producing aneconomical roller compacted concrete mix, a laboratory mix design has been performed. A detailed instructionhas sent to the laboratory and based on the engineer instructions tests have been done. No admixture has beenused in this phase of studies.

In this paper, summary of the mix design study results and fresh and hardened RCe properties have beenpresented. Test results of Loaded Vebe density, vebe time, compressive strength at different ages, modulus ofelasticity, dynamic elasticity modulus and permeability on Badovli samples have been presented and discussed.Key words: optimum mix, Badovli Dam, RCe

1 Introduction

BadovIi Dam is designed for agricultural purposesand providing potable water in North West of IRANin roller compacted concrete type. The dam will belocated in a high seismic area so it is necessary for thedam body to resist against dynamic forces (MCE=0.55 g).Rock type in abutments and foundation are limestone.Dam body concrete is roller compacted concrete witha compressive strength of 120 kg/cm2 which isrequired at. 180 days. Facings are conventional

concrete with a specified strength of 250 kg/cm2 at180 days also that is needed for durability againstfreezing and for tolerating the surface stressescaused by earthquake. All of the sluice works arelocated in the lower part of the dam in a eve type

concrete to ease Ree placing without anyinterference. Three galleries have been designed in

dam body for inspection, grouting and collectionleaked water in the dam body. Two horizontal

"'..,c.." .•_?"'-"'.c !.. ?w~e:ne.~ are predicted for inspection and instrumentations

and a perimetric gallery predicted for g~outing ofthe grout curtain during construction and afterconstruction for repairing purposes. The location ofgalleries designed to have minimum interference'

with RCe placing and all of galleries are located inthe evc.

Maximum spacing between contraction joints is18.5 mm, that is safe against cracking based on perfonnedthermal analysis. The thermal analysis showed therisk of mass gradient and surface gradient cracking islow and no cracking is expected in the dam body.

Because Badovli Dam is located in a cold

weather area, so it is important to have the minimumcement content in the CVC and RCe mix designs toreduce the cracking risk. For this reason a detailed

mix design program in design phase have beenpredicted.

'The main aim of this program was testing thequality of aggregates in a real mix ofRCC from strengthsand compaction degree points of view. The second

aim was determination of the mix efficiency and the

393

mInImum cement for reaching target strength. Theamount of cement is used in the thermal analysis andeconomical computation in the project.

In this program, fresh RCC tests were Vebe time

and Loaded Vebe density. Other tests performe~ onhardened RCC was compressive strength, elastic anddynamic elasticity modulus, hardened RCC densityand permeability.

+1, 587.00

E xcavtion line

GR 1 grouting &drainage gallery GR2

GR 1 grouting &drainage gallery GR1

CTJ...1.1 65350 N.W.L.. , . +1,660.00Left

Excavtion line

1--------\--d-----;~+--.---+------1--t-rG;r;;D~2-t---+------t7""i'V~~~~~-=---__:_-----j1+ 1,624.00

Fig. 1 longitudinal section of Badovli dam

2 Materials be used in the RCC as filler. This will be discussed later.

Cement components ofUromia IP cement

Table 1

2.2 Cement

Heat generation due to hydration of the cement istypically controlled by use of lower heat. of hydrationcements, use of less cement, and replacement of aportion of the cement with pozzolan or a combinationof these. Reduction of peak concrete temperature maybe achieved by other methods, such as reducedplacement temperatures. The selection of cement typeshould ¢onsider economics of cement procurement.

The ·nearest cement factory (320 km far from damsite), is the uromia cement plant. The total productionof the plant is 2,200 tid now and the plant was foundedin 1990.The plant produces Type I and IP whil.e theNatural pozzolan type is Dacite and Andesite tuffs. IPPortland pozzolan cement was picked up for the fIrstalternative of cementitious materials and otheralternative for pozzolan may be Turkish fly ash.

Because tests on borrow areas showed evidence ofalkali aggregate reactions, cementitious materials shallconsist of a portion of suitable pozzolan.

Si02 Ah0 3 F~03 CaO MgO S03 LOIBlaine

(%) (%) (%) (%) (%) (%) (cm2/g)

26.5 6.01 2.55 55.5 1.98 3.36 2.1 3,586

10o

Total grading envelope ofCI&C2-eS-C6 borrow areas

",. 1/1/1/ V

//1./

!."" -I/

"/~ /"~~

v

100 1000Size (mm)

. Fig. 2 Total envelope of Badovli borrow areas

100.0

= 90.0eQ) 80.0~

bO 70.0c::.~ 60.0

~ 50.040.030.020.010.00.0

o

2.1 Aggregates

Aggregates are obtained from four borrow areas witha gross volume of 1.4 million cubic meters. Theenvelope curve of these borrow areas are shown in theFig. 2. Although there are a far distance between borrowareas, .the total envelope doesn't show a wide rangeand this is a good property which let us to produceaggregates for RCC economically and uniformly.Detailed studies that have been performed on theseborrow areas showed the suitability of these borrowareas for production of RCC and conventional concrete.

Borrow areas mainly consist of limestone aggregates.B~sed on Borrow areas study, Clay is not present in

. the borrow areas so the passing of 75 micron sieve can

394

Grading curve of A,B & C aggregates

Loose bulk density Dry-rodded bulk density

(t1m~ (t1m3)

C I B I A C I B I A

1.4 I 1.539 I 1.690 1.580 I 1.691 I 1.905

v /V

/!

/v ij

/../

:1.1

Compacted density of Badovliaggregates (based on ASTM C-29)

Table 2

Crushing and impact values of the aggregates alsotested based on BS: 1881. During these tests, Anaverage of aggregate crushing value and impact valueof 12% and 20% obtained that shows aggregates aresuitable for making the RCC and can tolerate thepassing of the roller without important change in theirgrading.

The compaction results of combination of aggregates(Fig. 4) shows that sand weight shall be higher than35% of the aggregates. In the lesser amounts, densitydecreases rapidly. The higher amount of sand alsoleads the mix to a higher cohesiveness, that needshigher energy for compaction of the resulted roner

1-Sand 0-5 (A) -.- 5-25 (B) Unn 25-50 ( C) IFig. 3 Grading curve for Badovli aggregates

It is obvious from these figures that the sand has alarge amount of filler. Although these natural filler(silt) may have a light pozzolanic properties but notest have been performed to show this.

Elongated and flaky aggregates may decrease thecompacted density of aggregates and increase thecement and water content of the RCC. Elongated andflaky particles are less than 25% for coarse aggregatesin Badovli borrow areas according to the test results.The flaky and elongated tests have been performedbased on ASTM - D4791.

It should be mentioned that based on ACI, it ispossible to produce RCC by aggregates with less than50% flaky and elongated particles. So it is quitepossible to produce an economical RCCwith Badovliaggregates. Because sand (A fraction) has a goodcompaction density, it is suitable for making RCC andconcrete.

100~ 90.~ 80

~ 70~ 60R 50

40302010o

0.01 0.1 10 100

Size (rom)

2.3 Water

The water for production of RCC and conventionalconcrete obtained from Aghsu River. Based on studies,the properties of this water are like the potable waterbut in this stage of mix design, the potable water(Tehran water) has been used for production of mixes.

3 Required Compressive strength

The specific compressive strength of RCC for the dambody is 120 kg/cm2 based on the stability andstress-strain analysis. A safety margin of 95%specified for calculating the required mean strength.Because No information is available, a coefficient ofvariation of 16% was picked up for this stage ofstudies. So the average required strength for mixdesign will be calculated as below:

FCreq = 120 + 1.64 x 0.16 x 120 = 151 kg/cm2

The maximum size of aggregate picked up 50 mm.This size has been common now in RCC dams because ofless segregation potential than larger MSA's.

4 Quality testing on materials

The selection of aggregates and the control of aggregateproperties and grading are important factors influencingthe quality and uniformity of RCC production.Aggregates similar to those used in conventionalconcrete have been used in RCC. However, aggregatesthat do not meet the normal standards or requirements forconventional concrete have also been successfully usedin RCC dam construction.

After the sampling of aggregate and transportingthe materials to the laboratory, some test have beencarried out on the aggregate samples. These tests are:Gradation test (ASTM CI36), compacted density ofaggregate (ASTM C29), water absorption ofaggregates (ASTM CI27&C128), percentage of flakyand elongated particles (ASTM D4791).

Based on Atterberg limits tests (ASTM D4318),fines present in the borrow areas are not plastic.Plastic limit of the fines are 20-25, so the maximumfines content of the RCC mix shall be less than 9%.These fines help to the cohesiveness of the mix andare also helpful for increasing density and decreasingsegregation risk during the transportation and placingof the RCC.

In the laboratory, aggregates sieved and divided into A, B, C fractions and these three different aggregatefractions have been considered for Badovli dam;consist of 0 - 5 mm (A fraction), 5 - 25 mm (Bfraction) and 25 - 50 mm (C fraction). The grading ofthese fractions has shown in Fig. 3.

395

compacted concrete. Based on the results of Fig. 4, anAlBIC of 40%/40%/200/0 was picked up in this stageof mix designs.

cylinder moulds, a 9.1 kg surcharge is used but basedon ASTM C-1170, a 22.7 kg surcharge shall be used incompaction of samples in a VeBe mould.

Ag. 5 Density variation vs. sand content

•

2,350 2,450 2,550Measured density by VeBe

Final mix design of Badovli

2, 250 ~.;.......+-+--+--+-+--+--+--+--+--+__oI__+__oI__+___l

2,250

Table 3

0 2,550M

XV) 2,500;>'eJ:l..0"<l)

.~] 2,450eJ:l'-

~~ 2,400~

<l)

~ 2,350~<l)

~

Aggregates Loaded VeBe VeBeCement Water

Density time(kg) (kg)

A B C (kg/m3) (s)

160 115 40% 40% 20% 2,470 19

2,300 +-+---f--::y&-+--+--+--+--+--+--+--+--I-+--I-I-----I

Ag.6 VeBe measured density vs. cylindersmeasured density (all mixes)

Vebe time of the final mix design is about 19 secthat is a good consistency for Roller compactedconcrete. With a water/cement ratio of 0.72, a VeBedensity equal to 2,470 kg/m3 obtained (Table 3).

Measured density comparison

6 Hardened RCC properties

6.1 Compressive strength

Compressive strength tests are performed in the designphase .to determine mixture proportion requirements,and also to optimize combinations of cementitiousmaterials and aggregates. Compressive strength is usedto satisfy design loading requirements and also as anindicator of other properties such as durability.. Compressive strength of the final mix design

samples also measured based on ASTM C39 in 7, 28,90, 120 and 180 days age. Cylindrical specimens used formeasuring compressive strengths. Curve of compressivestrength changes in different ages for final mix design(Table 3) is shown in Fig. 7. Capping of cylinders inthe few fIrst samples showed that a great standarddeviation exists because of uncertainties in thisprocedure. So in the 180 days age capping omitted anda more uniform test results have been obtained.Because capping- of cylinders has a significant effecton measured compressive strength, care shall be takenon thickness and other parameters of the capping ofRCC. If it is not possible the top surface of RCC shall

396

444240

Sand cootent (percent ofaggregates)

38

Hardened RCC vs sand content

36

o 100

20 40

5-25

Fig. 4 Compacted density of differentamount of aggregates

•

~ ••/ ~

~~

~

• '"~-4

27 320

· 34

2 7440,,-..M

~ 2 7420

C27400.€

U)

5 27 380"'0U)

..£c.. 27360~U)

U 27 340~

100o

The cement content based on previousexperiences is 160 kg/m3.The samples have beenprepared in 15 cm x 30 cm cylindrical cast. Someother samples also have been prepared with differentamount of sand. Fig. 5 shows the variation of densityof hardened concretes vs. sand content. Based on theresults, the optimum sand content is about 38%, so asand content of 40% is acceptable for mix design.

5 Result of laboratory tests

Density of fresh roller compacted concrete sampleshave been measured by two methods: by Vebe apparatusand by cylindrical casts. Fig. 6 shows comparison ofthese two densities. Density measured by VeBeapparatus, is always lower than 15x30 cylinders andthis is due to the lower compaction energy in VeBeme~suring density. Based on ASTM C1176, incompaction of the 15x30 roller compacted concrete

be trowelled and be as smooth as possible.

~:--

L..-

L.----~-- :..---~

/--:--

/'

Compressive strength of Badovli roHer compactedconcretes

180~ 1605 140t:,-,. 120~ Me.~ ~ 100~ C 800. 60S8 40

20o

o 50 100 150 200

Age (d)

proportion (EdlEs) is higher and is about 1.67. In theearlier ages, this proportion may be higher due to thelower compressive strength. Dynamic elasticitymodulus test has been conducted at 28 & 180 days age.

Dynamic modulus of elasticity of RCCfs,-,. 32 ....--------------------et:S 31 -+---------------__---1

.2 30 -+-------------~----I:::3

"'0

E 29 -+-----------~~---------I~:g 28 -+------------:..",e----------I

£ 27 -f------~:..----------------I

Fig. 7 Compressive strength of the roller compacted concrete 26 -+----....,c;.-------- --1

25 -+-------r--------,-----.--------t

. Elasticity modulus of RCC's

6.2 Static elasticity modulus

Modulus of elasticity is typically a required inputparameter for most stress analysis programs. In linear­elastic numerical analysis, a low modulus of elasticitymay be desirable, since it may predict lower stressesfrom . an assumed linear stress-strain relationshipversus a high modulus material.

Modulus of elasticity of RCC samples, have beenmeasured based on ASTM C469. Fig. 8 shows the testresults of Elasticity modulus. .

/'v

'//

""/"

/"

V/ ....

./

VV

/'

I

150 200

Age (d)

150 200

Age (d)

100

100

50

50

Fig. 9 Dynamic elasticity modulus of Badovli

o

101-------.------..------..--------fo

121----------------------1

.-~ 20...---------------------1

]> ~~ 181--------~----..."",..-:::::--------I

~~ 16v ~~ 14...---------------------1

~

6.4 Indirect tensile strength

In the stress-strain analysis of the roller compactedconcrete dam, the direct tensile strength of the RCC isrequired. But in this stage, only indirect tests havebeen performed. By referring to the test results, adirect tensile strength of 16 kg/cm2 can be applied asdirect tensile strength of RCC at 180 days for Badovlisamples.

Indirect tensile strength ofRee's22,.--------------------

150 200

Age (d)

10050

Fig. 8 Static elasticity modulus of Badovli

8o

20

6.3 Dynamic modulus ofelasticity

Dynamic or rapid load concrete modulus for dynamicanalysi~ ··is accepted practice. Based on ACI207.5R avalue of instantaneous concrete modulus is approximately25% larger than the sustained modulus of elasticity andcan be used for preliminary studies in the absence ofactual laboratory test data.

Dynamic elasticity modulus of concrete is a necessaryparameter for performing linear dynamic analysis inConcrete dams. The test is based on the passing wavesthrough the concrete and measuring the velocity of thewave in the concrete. The standard of this test inBadovli Project was BS: 1881-part 209. By referring tothe results of the laboratory tests, in Badovli this

Fig. 10 Indirect tensile strength of RCC samples

6.5 Permeability

Although in the design of the dam body, the permeabilityof the RCC has not been taken into account, but thepermeability of the RCC's is an important factor inmix design because it can show the compact ability ofthe mixes. The lower the permeability of the samples,the higher the compaction of the mixes is. Maximumsize of aggregates has a second order effect on thepermeability of the RCC. If the MSA increases,permeability of the RCC also increases. The effect ofthe MSA is less than the effect of compatibility.

The permeability tests have been performed based on .

397

CRD-C 48 in the laboratory .Because during the test, thesamples have not been saturated, the samples crushedand an average penetration depth of water in samplesequal to 27 cm were reported. This is equal to acoefficient of permeability of 5xlO-10 cmls that is goodfor RCC and indicates the good compaction of thesamples.

References

[ 1J ACI 207.5R-99-Roller Compacted Mass concrete

398

[2J Badovli Mix design report (2007) Phase II studies[3J F.R.Andriolo, The Use of Roller Compacted

Concrete[ 4 J P, Kumar Mehta & Paulo. J. Monteiro ,Concrete:

Microstructure, Properties, and Materials[5 J ASTM C 1170- Standard Test Methods for

Determining Consistency and Density of Roller­Compacted Concrete Using a Vibrating Table

[6 J ASTM Cl176- Standard Practice for MakingRoller-Compacted Concrete in Cylinder MoldsUsing a Vibrating Table