Salma Dam - Afghanistan - RHA

A New Technical Approach of A New Technical Approach of

High Performance Concrete using High Performance Concrete using

Rice Husk Ash (RHA) in Cementitious Rice Husk Ash (RHA) in Cementitious Blend MaterialsBlend Materials

((Study on Abrasion resistance and water permeability and Thermal Properties)

R.B. Shivali, Senior Research OfficerR.B. Shivali, Senior Research Officer

CSMRS, New DelhiCSMRS, New DelhiPresently Dy. Chief Engineer

Salma Dam Project, Afghanistanand

Dr. D. Goldar, Former Principal Dr. D. Goldar, Former Principal

Delhi College of Engineering, New DelhiDelhi College of Engineering, New Delhi

INTRODUCTION

●● High performance concrete adopted for its increased compressive strength, improved durability & economic benefits and also for its positive impact on the environment.

● As strength and durability requirements of concrete for that concrete which satisfies a range of durability and other quality requirements, besides high strength.

● This improvement is both physical and chemical.● The ggbs, or flyash improve the cement packing and

the rice husk ash acts as a micro-filler in the space between the cement particles.

● The rice husk ash, being ultra fine and very high in reactive silicon dioxide reacts first, and fast.

● The ggbs and flyash react much slower, but over a period of time rice husk ash enhances the reaction effect.

RESEARCH SIGNIFICANCE

● ● Many projects face many problems, Many projects face many problems, such as cracking, seepage, such as cracking, seepage, abrasiveness and cracking due to abrasiveness and cracking due to thermal stresses. thermal stresses.

●● As such a very good solution is the As such a very good solution is the use use of of “A New Technical Approach of “A New Technical Approach of High Performance Concrete using Rice High Performance Concrete using Rice Husk Ash (RHA) in Cementitious Blend Husk Ash (RHA) in Cementitious Blend Materials”Materials” using Portland cement, ggbs, using Portland cement, ggbs, flyash and rice husk ash with super flyash and rice husk ash with super plasticizers/admixtures in suitable plasticizers/admixtures in suitable dosesdoses

SCOPE AND OBJECTIVE OF EXPERIMENTAL WORK

●● Three concrete mixes were prepared with different water cementitious ratios (w/c) varying from 0.22 to 0.30.

Cementitious: flyash: ggbs=40: 30: 30Cementitious: flyash: ggbs=30: 35: 35 Cementitious: flyash: ggbs=20: 40: 40

● The addition of rice husk ash ranged from 8 to 15 % by mass of cement with super plasticizers/admixtures in

suitable doses. ● Cubes and cylinders were cast to determine compressive strength, flexural strength, Non-destructive tests, abrasion-erosion resistance, permeability, and modulus of elasticity at age of 28 and 56 days. ● In this paper, based on experiment of above tests only, the conventional and 10%RHA details of abrasion-

erosion loss, the value of Coefficient of permeability and thermal properties behavioral parameters have been

reported.

EXPERIMENTAL INVESTIGATION

Materials

Cement- Ordinary Portland cement, 43 Grade (ACC brand).

Ground Granulated Blast furnace Slag (ggbs)- This is from steel factory Visakhapatanam, Andhra Pradesh.

Flyash- Flyash obtained from Badarpur - Dadri Thermal Power Plant.

Rice Husk Ash (RHA) – M/s N.K.Enterprises and Shree Shree Goursunder Rice & Oil Mills, Jharsuguda, Orissa.

Aggregates- Natural River sand and crushed coarse aggregate obtained from the crushing plant at Badarpur-U.P.

Superplasticizer- High range water reducing admixtures (HRWRA), Glenium B233 from MBT and Sikament 600N from Sika Qualcrete Pvt. Ltd.

Experimental investigations are carried out by various measures to establish the performance of concrete incorporating the “Cementitious Blend Materials” in respect of reducing cement content, lowering temperature rise due to hydration, minimizing cracking of mass concrete, produce and enhancing early age and induction of high strength, quality and durability of hydraulic concrete structures.

Cementitious Blend Materials - The amount of ggbs and flyash to be added to maintaining the compressive strength higher than that of conventional concrete, the ggbs (30%) & flyash (30%) content should be used to directly to replace the Cementitious (40%=30% portland cemen+10% RHA). To this end, by keeping the water cementitious ratio and maintaining an approximately equal workability, the mix proportions were determined.

The ultra fine particle size and high reactive silicon dioxide content of Rice Husk Ash brings up the potential of being much more reactive than the other supplementary cementitious materials. The combined effects of Cementitious Blend Materials can significantly reduce bleeding and segregation of the mixture. Because of its higher surface area, rice husk ash concrete may require a higher water demand for which HRWRA is used. The rice husk ash reacts with alkali (calcium hydroxide) in the cement which controls the alkali aggregate reaction in concrete.

LABORATORY INVESTIGATION

Specimens:Cube specimens of 150 mm (5.91 in.) size, cylinder

specimens of diameter 100 mm (3.94 in.) and height of 200 mm (7.87 in.) and of diameter 295 mm (11.6 in.) and

height of 100 mm (3.94 in.) were cast.

Items of Investigation/Test:a. At the age of 56 days, the concrete cylinders were tested to determine the Abrasion loss value over a period of 72 hours.b. At the age of 56 days, the concrete cube specimens were

tested to determine permeability to water, over a period of 168 hours, after achieving the equilibrium stage.

c. At the age of 28 and 56 days, the concrete cylinders were tested to determine the thermal properties (Thermal Conductivity, Specific heat and Diffusivity)

Equipment used:a. Abrasion-Erosion Test as per ASTM C-1138-1997. b. Permeability test as per IS: 3085-1965.c. Thermal properties as per ASTM standard

ANALYTICAL INVESTIGATION

Under Water Abrasion –Erosion loss as per ASTM C-1138-1997

The mass of the specimen in air and in water are determined before and after the test and the average depth of water calculated at the end of any time increment of testing based on the volume of abraded materials. It is calculated as follows:

ADA1 = VL/ A (1)Where, ADA1 = Average depth of abrasion at the end of the test increment in mA = Area of top of specimen in m2 VL = Volume of material lost during the test in m3VL = V1-V2V1 = Volume of specimen before testing in m3V2 = Volume of specimen at the end of the test increment in m3

The abrasion loss is also calculated by the following equation

L = (Mi – Mf)/ Mi (2)Where,L = Abrasion-erosion loss percent by massMi = Mass of the surface-dry specimen in kg. before test, andMf = Mass of the surface-dry specimen in kg. after test.

Permeability test as per IS: 3085-1965

The value of Coefficient of Permeability is determined to calculate as follows:

k= Q/{AT(H/ L)} (3)

Where,k= Coefficient of Permeability in cm/sec.Q= Quantity of water in milliliters percolating over the entire period of test after the steady state has been reachedA= Area of the specimen face in cm2

T= Time in seconds over which Q is measured H= Pressure head in kg/ cm2

L= Thickness of specimen in cm

Thermal properties as per ASTM standard

Thermal conductivity:Thermal conductivity of concrete varies with temperature, the variation being linear through the normal range of temperature.

The formula for conductivity of cylindrical specimen is given by

q [log e (b/a)] K= ------------------- (4)

2 L (a-b)

Where,

K= Thermal Conductivity of the concrete specimen expressed in Cal/sec/cm/0Cq= Rate of flow of heat in Cal/seca= Internal radius of hollow cylinder in cmb= External radius of hollow cylinder in cma= Temperature of radius a in 0Cb= Temperature of radius b in 0C L = Length of cylinder in cm

Specific Heat

Specific heat is the amount of heat required to raise the temperature of a unit mass of the material at 10C. The specific heat of concrete varies with temperature, the variation being linear through the normal range of temperature.

To calculate the temperature rise, the test is divided into three periods:

The initial period from Ti to ToThe heating period from To to Ta and The final period from Ta to TfThe temperature rise = Ta-To +Tc

Where,Tc is a correction factor sign of the temperature drift per interval during the heating period, calculated from the drifts determined during the initial and final periods

Diffusivity

Diffusivity is an index of the facility with which a material will undergo temperature change. Diffusivity was computed from Conductivity, specific heat and density using the relation:

Diffusivity = K/ (C) (5)

Where,

K= Thermal conductivity of concreteC= Specific Heat of concrete= Unit weight of saturated concrete

RESULTS OF EXPERIMENTAL WORKS

Comparison of Abrasion Loss value: Based on experimental results, the Abrasion-Erosion loss values of three mixes (Cementitious: flyash: ggbs=40: 30:30, 30: 35:35 and 20:40:40) for conventional as well 10% RHA with different w/cementitious (w/c) ratio are shown in the Table 1-3 and graphs plotted accordingly are also shown in the Figures 1-6.

Comparison of Permeability value:The Coefficient of Permeability values of three mixes (Cementitious: flyash: ggbs=40: 30:30, 30: 35:35 and 20:40:40) for conventional as well 10% RHA with different w/cementitious (w/c) ratio are shown in the Table 4-6 and plotted graphs accordingly are shown in the Figures 7-12.

Comparison of Thermal properties:The Thermal properties (thermal conductivity, specific heat and diffusivity) of three mixes (Cementitious:flyash: ggbs=40: 30:30, 30: 35:35 and 20:40:40) for conventional as well 10% RHA with different w/cementitious (w/c) ratio are shown in the Table 7-10 ands plotted graphs are also shown in the Figures 13-18.

The best results gained by using 10% Rice Husk Ash with cement, ggbs and flyash replacement by 30 % each at w/cementitious (w/c) ratio of 0.22

Abrasion LossTable1: Abrasion loss value after 72 Hours (at 12 hr. interval) of

concrete mix using cement, flyash and ggbs with rice husk ash

Concrete mix: Cementitious: flyash: ggbs=40:30:30

Time (hrs.)

At w/c=0.22 At w/c=0.26 At w/c=0.30

Conventio-nal Abrasion Loss (%)

10% RHA Abrasion Loss (%)





12 0.130 0.090 0.175 0.120 0.216 0.150

24 0.230 0.160 0.285 0.215 0.346 0.258

36 0.305 0.210 0.375 0.285 0.451 0.346

48 0.365 0.245 0.445 0.335 0.528 0.409

60 0.410 0.270 0.500 0.370 0.597 0.452

72 0.445 0.289 0.538 0.390 0.645 0.485

Abrasion Loss Concrete Mix: Cementitious: flyash: ggbs = 40:30:30

Abrasion Loss Value

0.0

0.10.2

0.3

0.4

0.50.6

0.7

0 20 40 60 80Time (Hrs.)

Abr

asio

n L

oss

(%)

Conventional at w/c=0.22Conventional at w/c=0.26Conventional at w/c=0.30

Fig. 1

Abrasion Loss Value

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0 20 40 60 80

Time (Hrs.)

Ab

rasi

on L

oss

(%

)

Abrassion loss with 10% RHA at w/c=0.22Abrassion loss with 10% RHA at w/c=0.26Abrassion loss with 10% RHA at w/c=0.30

Fig. 2

Time Time (hrs.) (hrs.)

At w/c=0.22At w/c=0.22 At w/c=0.26 At w/c=0.26 At w/c=0.30 At w/c=0.30

Conventi-Conventi-onal onal Abrasion Abrasion Loss (%)Loss (%)

10% RHA 10% RHA Abrasion Abrasion

Loss(%)Loss(%)



Loss(%)Loss(%)



Loss(%)Loss(%)

1212 0.1720.172 0.1060.106 0.2110.211 0.130.13 0.253 0.253 0.1550.155

2424 0.2520.252 0.1670.167 0.3150.315 0.2100.210 0.3770.377 0.2520.252

3636 0.3290.329 0.2190.219 0.4000.400 0.2800.280 0.4710.471 0.3320.332

4848 0.3940.394 0.2680.268 0.4850.485 0.3400.340 0.5650.565 0.4100.410

6060 0.4490.449 0.2980.298 0.5470.547 0.3910.391 0.6400.640 0.4750.475

7272 0.5000.500 0.3150.315 0.6000.600 0.4300.430 0.7050.705 0.5250.525

Table2: Abrasion loss value after 72 Hours (at 12 hr. interval) of concrete mix using cement, flyash and ggbs with rice husk ash


Concrete Mix: Cementitious: flyash: ggbs = 30:35:35

Abrasion Loss Value

0

0.1

0.2

0.30.4

0.5

0.6

0.7

0.8

0 20 40 60 80Time (Hrs.)

Ab

rasi

on

Loss

(%

)

Conventional loss at w/c=0.22Conventional loss at w/c=0.26Conventional loss at w/c=0.30

Fig. 3

Abrasion Loss Value

0

0.1

0.2

0.3

0.4

0.5

0.6

0 20 40 60 80Time (Hrs.)

Ab

rasi

on

Lo

ss (

%)

Abrasion loss with 10% RHA at w/c=0.22Abrasion loss with 10% RHA at w/c=0.26Abrasion loss with 10% RHA at w/c=0.30

Fig. 4

Time (hrs.)

At w/c=0.22 At w/c=0.26 At w/c=0.30

Conventi-onal Abrasion Loss (%)

10% RHA Abrasion

Loss(%)


10% RHA Abrasion

Loss(%)


10% RHA Abrasion

Loss(%)

12 0.190 0.126 0.230 0.150 0.267 0.185

24 0.283 0.192 0.348 0.242 0.395 0.283

36 0.365 0.251 0.445 0.321 0.512 0.373

48 0.435 0.305 0.529 0.389 0.616 0.459

60 0.495 0.348 0.609 0.450 0.711 0.535

72 0.546 0.388 0.679 0.500 0.801 0.595

Table3 : Abrasion loss value after 72 Hours (at 12 hr. interval) of concrete mix using cement, flyash and ggbs with rice husk ash



Abrasion Loss Value

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80Time (Hrs.)

Ab

rasi

on L

oss

(%

)

Conventional loss at w/c=0.22Conventional loss at w/c=0.26Conventional loss at w/c=0.30

Fig. 5

Abrasion Loss Value

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 20 40 60 80

Time (Hrs.)

Abr

asio

n L

oss

(%)

Abrasion loss with 10% RHA at w/c=0.22Abrasion loss with 10% RHA at w/c=0.26Abrasion loss with 10% RHA at w/c=0.30

Fig. 6

Test Duration(Hrs)

At w/c=0.22 At w/c=0.26 At w/c=0.30

Convent. CumulativeCoef. ofPermeability

10% RHA CumulativeCoef. ofPermeability





m/sec.*10-12

m/sec.*10-12

m/sec. *10-12

m/sec. *10-12

m/sec. *10-12

m/sec. *10-12

24 0.336 0.233 0.423 0.28 0.52 0.335

48 0.498 0.341 0.584 0.403 0.693 0.48

72 0.623 0.431 0.707 0.504 0.86 0.585

96 0.733 0.511 0.837 0.591 0.968 0.67

120 0.824 0.60 0.933 0.68 1.055 0.75

144 0.91 0.66 1.016 0.742 1.13 0.807

168 0.966 0.698 1.08 0.776 1.191 0.85

Permeability (Coeff. of Permeability)Table4: Permeability value after 168 Hours (at 24 hr. interval) of concrete

Pressure Head=15Kg/cm2


Permeability (Coeff. of Permeability)Concrete Mix: Cementitious: flyash: ggbs=40:30:30

Coef. of Permeability Development of Conventional Concrete at different w/c

00.20.40.60.8

11.21.4

0 20 40 60 80 100 120 140 160 180Time (Hrs.)

Coef

. of

Per

mea

bility

*10-1

2 m/s

ec.


Fig. 7

Coef. of Permeability Development of 10% RHA based Concrete at different w/c ratio w/c

0

0.2

0.4

0.6

0.8

1

0 50 100 150 200Time (Hrs.)

Coe

f. o

f P

erm

eabi

lity

*10-1

2 m/s

ec.

10% RHA at w/c=0.2210% RHA at w/c=0.2610% RHA at w/c=0.30

Fig. 8

Test Duration(Hrs)

At w/c=0.22 At w/c=0.26 At w/c=0.30Convent. CumulativeCoef. ofPermeability

10% RHA CumulativeCoef. ofPermeabilit

y



y

Conventional CumulativeCoef. ofPermeability


m/sec.*10-12

m/sec.*10-12

m/sec. *10-12

m/sec. *10-12

m/sec. *10-12

m/sec. *10-12

24 0.442 0.32 0.528 0.395 0.62 0.48

48 0.592 0.462 0.715 0.547 0.82 0.615

72 0.76 0.59 0.888 0.67 1.01 0.742

96 0.925 0.694 1.05 0.77 1.176 0.84

120 1.067 0.77 1.188 0.86 1.307 0.92

144 1.189 0.84 1.32 0.92 1.413 0.985

168 1.258 0.897 1.38 0.957 1.494 1.032

Table5: Permeability value after 168 Hours (at 24 hr. interval) of concrete mix using cement, flyash and ggbs with rice husk ash

Concrete mix: Cementitious : flyash: ggbs=30:35:35



00.20.40.60.8

11.21.41.6

0 25 50 75 100 125 150 175 200Time (Hrs.)

Coe

f. o

f P

erm

eabi

lity

*10-1

2 m/s

ec.


Fig. 9


0

0.2

0.4

0.6

0.8

1

1.2

0 25 50 75 100 125 150 175 200Time (Hrs.)

Coe

f. o

f Pe

rmea

bilit

y *1

0-1

2 m

/sec

.

10% RHA at w/c =0.2210% RHA at w/c =0.2610% RHAc at w/c =0.30

Fig. 10

Test Duration(Hrs)

At w/c=0.22 At w/c=0.26 At w/c=0.30Convent. CumulativeCoef. ofPermeability


y



Conventional CumulativeCoef. ofPermeability


y

m/sec.*10-12

m/sec.*10-12

m/sec. *10-12

m/sec. *10-12

m/sec. *10-12

m/sec. *10-12

24 0.508 0.357 0.644 0.43 0.79 0.50

48 0.69 0.496 0.85 0.578 1.02 0.65

72 0.87 0.606 1.059 0.675 1.22 0.749

96 1.04 0.714 1.22 0.80 1.378 0.87

120 1.228 0.82 1.38 0.90 1.538 0.96

144 1.36 0.89 1.53 0.965 1.657 1.03

168 1.48 0.939 1.591 1.009 1.73 1.08

Table6: Permeability value after 168 Hours (at 24 hr. interval) of concrete mix using cement, flyash and ggbs with rice husk ash




0

0.5

1

1.5

2

0 25 50 75 100 125 150 175 200

Time (Hrs.)

Coe

f. o

f Pe

rmea

bilit

y *1

0-1

2 m

/sec

.


Fig. 11


0

0.2

0.4

0.6

0.8

1

1.2

0 25 50 75 100 125 150 175 200

Time (Hrs.)

Coe

f. o

f P

erm

eabi

lity

*10-1

2 m/s

ec.

10% RHA at w/c=0.2210% RHA at w/c=0.2610% RHA at w/c=0.30

Fig. 12

Time (Day) At w/c=0.22 At w/c=0.26 At w/c=0.30

Conventional

Thermal conductivity

10% RHAThermal conductivity

Conventional


10% RHA Thermal conductivity

Conventional Thermal conductivity

10%RHAThermal conductivity

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

0 0 0 0 0 0 0

28 1.830 1.770 1.7503 1.7134 1.700 1.660

56 1.780 1.730 1.7034 1.6641 1.6200 1.590

Thermal Properties

Table7: Thermal conductivity test of concrete mix using cement, flyash and ggbs with rice husk ash


Thermal PropertiesConcrete Mix: Cementitious: flyash: ggbs = 40:30:30

Thermal Conductivity(Joule/m/sec/0C) Development of Conventional Concrete at different w/c

00.20.40.60.8

11.21.41.61.8

2

0 10 20 30 40 50 60Age in Days

Th

erm

al C

on

du

ctiv

ity

(Jo

ule

/m/s

ec/0

C)

Conventional Th. Conductivity at w/c=0.22Conventional Th. Conductivity at w/c=0.26Conventional Th. Conductivity at w/c=0.30

Fig. 13

Thermal Conductivity (Joule/m/sec/0C) Development of 10% RHA based Concrete at different w/c ratio

0

0.5

1

1.5

2

0 10 20 30 40 50 60Age in Days

The

rmal

Con

duct

ivity

(Jou

le/m

/sec

/0C)

Th. Conductivity with 10% RHA at w/c=0.22Th. Conductivity with 10% RHA at w/c=0.26Th. Conductivity with 10% RHA at w/c=0.30

Fig. 14


Conventional



Conventional





Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

0 0 0 0 0 0 0

28 1.810 1.770 1.7412 1.6931 1.6900 1.630

56 1.730 1.690 1.6874 1.6382 1.6100 1.570

Table8: Thermal conductivity test of concrete mix using cement, flyash and ggbs with rice husk ash

Concrete mix: Cementitious: flyash: ggbs=30:35: 35



0

0.5

1

1.5

2

0 10 20 30 40 50 60Age in Days

The

rmal

Con

duct

ivity

(Jou

le/m

/sec

/0C)

Conventional Th. Coductivity at w/c=0.22Conventional Th. Coductivity at w/c=0.26Conventional Th. Coductivity at w/c=0.30

Fig. 15

Thermal Conductivity(Joule/m/sec/0C) Development of 10% RHA based Concrete at different w/c ratio

00.20.40.60.8

11.21.41.61.8

2

0 10 20 30 40 50 60Age in Days

The

rmal

Con

duct

ivity

(Jou

le/m

/sec

/0C)

Th. Coductivity with RHA at w/c=0.22Th. Coductivity with RHA at w/c=0.26Th. Coductivity with RHA at w/c=0.30

Fig. 16


Conventional



Conventional




10% RHA10% RHAThermal Thermal conductivityconductivity

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/sec/0C

Joule/m/Joule/m/sec/0sec/0CC

0 0 0 0 0 0 00

28 1.7601 1.730 1.710 1.6778 1.640 1.6201.620

56 1.7001 1.680 1.6681 1.6189 1.6100 1.5701.570

Table9:Thermal conductivity test of concrete mix using cement, flyash and ggbs with rice husk ash




0

0.5

1

1.5

2

0 10 20 30 40 50 60Age in Days

The

rmal

Con

duct

ivity

(Jou

le/m

/sec

/0C)

Conventional Th. Conuctivity at w/c =0.22Conventional Th. Conuctivity at w/c =0.26Conventional Th. Conuctivity at w/c =0.30

Fig. 17

Thermal Conductivity(Joule/m/sec/0C) Development of 10% RHA based Concrete at different w/c ratio

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 10 20 30 40 50 60Age in Days

Ther

mal

Con

duct

ivity

(J

oule

/m/s

ec/0

C)

Th. Conductivity with 10% RHA atw/c=0.22



Fig. 18

Concrete mix w/c ratio

Specific heat (Joule/kg/0C)

Diffusivity(m2/hr)

Conventional

10% RHA

Conventional

10% RHA

Cementitious: flyash: ggbs = 40:30:30

0.22 1017 930 0.00175 0.00141

0.26 1010 921 0.00152 0.0012

0.30 1002 918 0.00129 0.0010

Cementitious: flyash: ggbs= 30:35:35

0.22 1012 822 0.00145 0.0011

0.26 1009 919 0.0012 0.00097

0.30 986 910 0.00102 0.0009

Cementitious: flyash: ggbs = 20:40:40

0.22 1000 912 0.00126 0.00098

0.26 992 908 0.0011 0.0009

0.30 985 896 0.001 0.00085

Table10: Specific heat and diffusivity of concrete mix using cement, flyash and ggbs with rice husk ash

CONCLUSION

These results of tests carried out by “A New Technical Approach of High Performance Concrete using Rice Husk Ash (RHA) in Cementitious Blend Materials” indicate that concretes of greatly reduced abrasion value and permeability at age of 56 days and the best results achieved by using 10% rice husk ash with w/c ratio at 0.22 as compared to conventional concrete mix and other w/c ratio of 0.26 and 0.30 though a minor change in the blend of materials having more quantity of fine aggregate than coarse aggregate for the concrete mix (cementitious:flyash:ggbs=40:30:30) as compare to other mixes (cementitious:flyash: ggbs=30: 35:35 and cementitious: flyash: ggbs=20:40:40). The thermal properties at age of 28 & 56 days obtained also show the thermal conductivity, specific heat and diffusivity in the approachable manner. This is probably due to a better mix distribution. Since the cement content is drastically reduced by using such combination the proposal is economically viable.

ACKNOWLEDGEMENT

The authors wish to express their gratitude and sincere appreciation to Sh. N.P.Singhania, CEO for N.K.Enterprises and Shree Shree Goursunder Rice & Oil Mills, Jharsuguda, Orissa for providing Rice Husk Ash, cement and his guidance.

Gratitude is also expressed to Sika and MBT Cos. for super plasticizers/admixtures.

The authors also wish to express special gratitude and appreciation to Deptt. of CSMRS for testing equipments and facilities. Gratitude is also expressed to Sh. P.K.Jha, S.R.O. in-charge and Sh. Raj Kumar, RO, Sh. S.N.Singh and Sh. Vinod Naudiyal sub-in-charge of Permeability, Abrasion erosion resistance and Thermal conductivity testing equipment for providing the laboratory facilities and gratitude is also due to Sh.Ram Niwas, Sh.Rakesh and Sh.Bhuwan Chand who helped for casting, testing of samples as and when called in laboratories to make success.

Documents

Salma Dam - Afghanistan - RHA