BEHAVIOUR OF SELF COMPACTING CONCRETE MADE WITH GGBS

AND RHA UNDER AXIAL COMPRESSION AND FLEXURE

Synopsis of the Thesis proposed to be submitted

By

MUDDAPU SWAROOPA RANI

(Reg.No.30514 CE/PH)

for the award of the degree of

DOCTOR OF PHILOSOPHY

IN

CIVIL ENGINEERING

RESEARCH AND DEVELOPMENT CELL

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY

HYDERABAD – 500 085, A.P., INDIA

JANUARY 2011

Contents Page No.

1.0 Introduction 1

1.1 Significance of the present research 1

1.2 Literature Review 2

1.3 Objectives and scope of the work 3

1.4 Materials used 4

1.5 Development of SCC ad studies on fresh and

hardened properties 6

1.5.1 GGBS based SCC mixes 6

1.5.2 Blending of RHA to SCC mixes 7

1.6 Selection of Final SCC Mixes 8

1.7 Evaluation of Strength Efficiency Factors 9

1.7.1 Estimation of Strength Efficiency Factor, k 9

1.8 Development of SCC with Steel Confinement

11

1.8.1 Studies on Stress- Strain Behaviour of SCC

11

1.8.2 Models for Stress-Strain Behaviour of SCC

Mixes

12

1.8.3 Development of Theoretical Stress-Strain

Curves 15

1.9 Studies on Flexural Behaviour of SCC mixes

15

1.10 Development of Moment-Curvature

relationships using Analytical Models. 16

1.11 Durability Studies of Low, Medium and high

grade SCC Mixes with GGBS and RHA. 18

1.12 Conclusions 19

1.13 Some Important References 21

List of publications of the author related to

the present work

24

Table No. Table Page.No

1.5.1.1 SCC mixes with optimum GGBS 6

1.5.1.2 Fresh and Hardened properties of SCC with

GGBS

7

1.5.2.1 SCC mixes with GGBS and RHA 7

1.5.2.2 Fresh and Hardened Properties of SCC with

GGBS and RHA

8

1.6.1 Final SCC mix proportions selected for

further investigations

8

1.7.1 Comparison of Strength Efficiency factor ’k’ of

GGBS and RHA combination in SCC and

GGBS alone in SCC at optimum % of

replacement

10

1.8.1 Designation for M20 grade SCC concrete 12

1.11.1 Acid Durability & Acid Attack Factors for

different SCC Mixes

18

Fig. No Figure

1.7.1 Relation between Efficiency Factor ‘k’ and Age with % of GGBS replacement for M20

SCC at 3, 7, 28 days

10

1.8.1 Stress-Strain behaviour M2S, M2S1, M2S2,

M2S3, M2S4, M2S5, M2S6 Mixes

12

1.8.2 Normalised Stress-Strain behaviour of M20-GGBS

13

1.8.3 Experimental & Theoretical Stress-Strain -

M2S4

15

1.9.1 Load-deflection plots for over -reinforced beams

16

1.10.1 Experimental and Theoretical M-Ф plots for beam UR & OR of M2S-mix

17

1.11.1 Acid Durability Factor and Days of immersion of M20 grade SCC mixes in

H2SO4 Acid

19

1

SYNOPSIS

1.0 INTRODUCTION

Concrete technology has made tremendous strides in the past

decade. The development of specifying a concrete according to its

performance requirements, rather than the constituents and ingredients

has opened innumerable opportunities for producers of concrete and

users to design concrete to suit their specific requirements. One of the

most outstanding advances in the concrete technology over the last

decade is “self compacting concrete” (SCC). Self-compacting concrete is a

highly flowable, stable concrete which flows readily into places around

congested reinforcement, filling formwork without any consolidation and

significant segregation. The hardened concrete is dense, homogeneous

and has the same engineering properties and durability as that of

traditional vibrated concrete. The use of SCC eliminates the need for

compaction thereby saves time, reduces labour costs and conserves

energy. Furthermore use of SCC enhances surface finish characteristics.

1.1. SIGNIFICANCE OF THE PRESENT RESEARCH

Extensive studies have been made on Self Compacting Concrete

with different combinations of mineral and chemical admixtures (chapter

2). However, Limited studies were done on the behaviour of SCC with

GGBS, SCC with RHA and SCC with GGBS and RHA combination and its

2

efficiency. Considering this gap in existing literature an attempt has been

made to study the strength efficiency of GGBS and RHA in SCC along

with their mechanical strength and durability aspects.

1.2. LITERATURE REVIEW

More than hundred papers are reviewed and presented in the main

thesis, out of which few important reports have been presented. Self

compacting concrete was developed at first in Japan by Prof.Okamura

[8] of Kochi university of Technology in 1986. Studies to develop SCC and

its workability have been carried out by Ozawa & Maekawa at the

University of Tokyo. Research scholars all over the globe have reported

the need of admixtures in SCC. H.Okamura & M. Ouchi (1997) [9] have

investigated the effect of superplasticiser on the balance between

flowability and viscosity of mortar in SCC. K.Ganesh Babu and V. Sree

Rama Kumar (2000) [ 4] quantified the 28-day cementitious efficiency of

ground granulated blast furnace slag (GGBS) in concrete at the various

replacement levels. Nan Su et al (2001) [6], Okamura H (2003) [8] and

EFNARC guidelines (2002 & 2005)[15] have proposed the mix design

methods for SCC using different mineral admixtures. Many investigators

have reported the use of fly ash, GGBS etc. as filler materials in SCC.

Suresh Babu. T (2009)[14] has studied elaborately about stress-strain

behavior of SCC and GFRCC with different admixtures.

3

Mehta P.K (1977)[5], Seshagiri Rao M.V (1999)[12], Rama Rao G.V

(2004)[13] have reported the effective use of RHA as an admixture to

improve the strength characteristics. Papworth (1994) [10], D.R. Seshu

(2003)[3] have presented models for the stress-strain behaviour of

conventional, fibre reinforced and steel fibre reinforced self compacting

concrete mixes respectively. Annie Peter (2007)[2] have reported the

flexural behaviour of steel fibre reinforced SCC.

1.3. OBJECTIVES AND SCOPE OF THE WORK

Even though extensive work is reported on SCC not much work is

reported on the behavior of SCC with GGBS and RHA as mineral

admixtures. Keeping this in view, the present experimental is taken up

to study the behavior of combination of GGBS and RHA in different

grades (M20, M40 and M60, i.e low, standard and high grade) of

concrete mixes. The main aim is to obtain specific experimental data,

to understand fresh and hardened properties of the self compacting

concrete with GGBS and RHA. Further it is also aimed to study

durability aspects of GGBS and RHA SCC. Broadly the main aims of

the present investigation are.

1. To study the behaviour of SCC

a. With GGBS

b. With GGBS and RHA combination

4

2. To investigate the compatibility of above powders in SCC along with

other chemical admixtures (SP and VMA).

3. To arrive at the Strength Efficiency factors of GGBS and RHA in

SCC.

4. To study the Stress-Strain Behaviour.

5. To study the Flexural Behaviour of beams.

6. To study the Durability aspect of SCC made with GGBS and RHA.

1.4. MATERIALS USED

Cement 53 grade OPC conforming to IS-12269

having specific gravity of 2.91.

Fine Aggregate Natural river sand conforming to IS-383

Zone II, having specific gravity 2.59.

Coarse Aggre Coarse Aggregate Crushed angular aggregate of size10 mm

having specific gravity 2.61.

Mineral admixtures Ground granulated blast furnace slag

Conforming to BS 12089-1987.

Rice Husk Ash (RHA)

Chemical admixtures High range water reducer,

Viscosity Modifying Agent (VMA).

Water Conforming to IS 456-2000.

Glass Fibres Acids H2SO4, HCl, Na2SO4.

5

Properties of the materials in detail are presented in the main thesis.

The Rice Husk Ash is obtained by burning the Rice Husk, obtained

from local mills, in heaps of 20 to 30kg in open air and grinding it to

16000cm2/gm. It is reported by M.V Seshagiri Rao that ash prepared by

this method gives good reactivity. The entire procedure is shown below

PREPARATION OF RICE HUSK ASH

20kg-30kg Rice Husk

heaps are made

Burnt in open air in

heaps of 20kg below

700oc

unburnt rice husk (black

in colour) is removed

Whitish grey ash is

ground in ball mills

Rice Husk Ash rich in

amorphous silica of

fineness 16000cm2/gm

obtained is highly reactive

6

1.5 DEVELOPMENT OF SCC AND STUDIES ON FRESH AND

HARDENED PROPERTIES

The first phase of investigation was carried out to develop a SCC

mix of low, medium and high strength concrete using chemical

admixtures. The mix proportion was designed based on EFNARC

method of SCC mix design. The designed mix was later extended to the

mineral admixture GGBS of different percentages. Further these mixes

and their combinations were blended with small quantities of RHA and

its fresh and hardened properties studied. Finally eight SCC mixes

which have yielded high compressive strength with satisfactory fresh

properties were selected and taken for further investigations.

1.5.1 GGBS based SCC Mixes

The SCC mix proportions with GGBS as filler material were

designed. Different trial mixes were tested in the laboratory and the

mixes with satisfactory fresh properties were selected as GGBS mix

proportions. GGBS mix proportions and their properties are shown in

tables 1.5.1 & 1.5.2.

Table 1.5.1.1 SCC mixes with optimum GGBS

SNo Desig- nation

cement Kg.

C.A Kg

F.A Kg

GGBS kg

Water kg

S.P %

(bwp)

V.M.A %

1 M20 280 780 844 120 180 0.62 0.062

2 M40 350 800 800 150 190 0.82 0.082

bwp- by weight of powder

7

Table 1.5.1.2 Fresh and Hardened properties of SCC with GGBS

1.5.2 Blending of RHA to SCC Mixes

Rice husk ash is blended at different percentages to the GGBS mix and

its effect on fresh and hardened properties are shown in Tables 1.5.2.1 &

1.5.2.2.

Table 1.5.2.1 SCC mixes with GGBS and RHA

S.

no

Mix

Cement

kg.

C.A

kg

F.A

kg

RHA

kg*

GGBS

kg

Water

kg

S.P

%

VMA

%

1 M20 280 780 844 3.60* 116.40 180 0.68 0.07

2 M40 350 800 800 4.50* 145.50 190 0.84 0.08

3 M60 450 660 810 30** 150 190 0.98 0.01

* Optimized GGBS is replaced by 3% RHA by weight. ** 5% of RHA added by weight of

optimised GGBS

Desig

nati

on

Fresh properties Hardened properties

Slump Test V Funnel Test L Box Test

Strength at 28 days N/mm2

Slump

mm

T50

time

Sec.

Time for

Discharge

T5 min.

Sec.

H2/H1 Compressive strength Tensile

strength

Flexural

strength

3d 7d 28d

M20 750 3.89 7.02 8.68 0.98 12.86 22.13 36.89 3.15 3.82

M40 760 3.80 6.78 8.25 0..98 16.11 31.75 52.67 4.67 4.98

8

Table 1.5.2.2 Fresh and Hardened Properties of SCC with GGBS and RHA

1.6 Selection of Final SCC Mixes

The selected eight SCC mixes along with fresh are shown in tables

1.6.1.

Table 1.6.1 Final SCC mix proportions selected for further investigations

S

.

no

Design-

ation

Cement

kg

C.A

kg

F.A

kg

GGBS

kg

RHA

kg

Water

kg

S.P %

(bwp)

VMA

%

1 M20 400 780 844 0 0 180 0.80 0.08

2 M20-

GGBS 280 780 844 120 0 180 0.62 0.06

3 M20-GGBS

-RHA

280 780 844 116.4 3.60 180 0.68 0.07

4 M40 500 800 800 0 0 190 1.00 0.01

5 M40-

GGBS 350 800 800 150 0 190 0.82 0.08

6 M40-GGBS

-RHA

350 800 800 145.5 4.50 190 0.84 0.08

7 M60 600 660 810 0 0 180 1.00 0.01

8

M60-

GGBS

-RHA

450 660 810 150 30 190 0.98 0.01

Desig

nation

Fresh properties Hardened properties

Slump Test V Funnel Test L Box Test

Strength at 28 days N/mm2

Slump mm

T50 time

Sec.

Time for

Discharge

T5 min. Sec.

H2/H1

Compressive strength

Tensile

strength

Flexural strength

3d 7d 28d

M20 750 4.20 7.20 8.6 0.98 14.30 22.20 41.20 3.829 4.20

M40 760 4.00 5.90 8.35 0..98 20.80 32.50 58.25 4.720 5.40

M60 720 3.24 6.54 8.37 0.96 18.89 39.97 65.52 5.680 5.98

9

1.7 EVALUATION OF STRENGTH EFFICIENCY FACTORS

The present work is an effort to quantify the 3, 7 and 28-day

cementitious efficiency of ground granulated blast furnace slag (GGBS)

and Rice Husk Ash (RHA) combination in SCC at various replacement

levels by using a Cementing Efficiency Factor (k). The strength efficiency

factors are mainly useful to describe the admixtures GGBS and RHA

combination‟s ability on the compressive strength of SCC and quantify

the replacement of cement by GGBS and RHA combination on a one-to-

one basis by weight.

1.7.1 ESTIMATION OF STRENGTH EFFICIENCY FACTOR, K

The Bolomey‟s empirical expression frequently used to predict the

strength of concrete is theoretically well justifies when applied to

hardened SCC. The well known Bolomey‟s equation often used to relate

strength and water/cement ratio is:

S = A [(C/W)] + B ------ (1)

S is the compressive strength in MPa,

C is the cement content in kg /m3,

W is the water content in kg/m3

A and B are Bolomey‟s coefficients /or constants

A strength efficiency factor, k, can then be computed using modified

Bolomey‟s equation

10

S = A [(C+ kG)/W) – 0.5] ---------- (5)

Where S is the compressive strength in MPa,

C is the cement content in kg/m3,

G is the amount of GGBS and RHA replaced bwc.

W is the water content in kg/m3 and k denotes efficiency factor of GGBS

and RHA combination

Table 1.7.1 Comparison of Strength Efficiency factor ‟k‟ of GGBS

and RHA combination in SCC and GGBS alone in SCC at optimum %

of replacement

Admixture

Efficiency Factor „k‟(For optimum % replacement)

M20 Grade M40 Grade M60 Grade

3 Days

7 Days

28 Days

3 Days

7

Days

28 Days

3 Days

7 Days

28 Days

GGBS 0.77 1.21 1.80 0.69 1.15 1.56 0.63 0.33 0.66

GGBS and RHA

1.03 1.22 2.19 0.73 1.21 1.90 0.69 0.90 1.31

Fig 1.7.1 Relation between Efficiency Factor „k‟ and Age with

% of GGBS replacement for M20 SCC at 3, 7, 28 days

11

1.8 DEVELOPMENT OF SCC WITH STEEL CONFINEMENT

With all the eight selected SCC mixes the cylinders are cast with

steel confinement. For all the eight mixes the steel rings inserted were

3 rings, 4 rings, 5 rings .The rings are made of M.S bars of diameter

4mm and 6mm. These cylinders were further tested for stress-strain

behaviour. The percentage of steel confinement is shown in the table

below

No. of rings

0 rings

3 rings

of 4mm

dia

4 rings

of 4mm

dia

5 rings

of 4mm

dia

3 rings

of 6mm

dia

4 rings

of 6mm

dia

5 rings

of 6mm

dia

Percentage of steel

confinement

0

0.79

1.06

1.32

1.82

2.43

3.04

1.8.1 STUDIES ON STRESS- STRAIN BEHAVIOUR OF SCC

In this phase of investigation the stress-stain behavior of SCC with

GGBS and RHA for final mixes are studied. A total number of 168

cylinders are cast with and without steel confinement and tested after

28 days of normal curing under water. The cylinders are tested for

stress-strain behavior under uni-axial compression. For each mix 3

cylinders are tested and the average stress-strain curve for each mix is

plotted. The designations of M20 grade concrete with and without steel

confinement are shown in Table 1.8.1 similarly, designations of M40

and M60 are presented in main thesis. The values of stresses and

strains obtained experimentally are plotted and one stress-strain curve

12

for M20 is shown in figure 1.8.1.Similarly for M40 and M60 stress

strain curves are plotted and presented in main thesis.

Table 1.8.1. Designation for M20 grade SCC concrete

S No

Description

Percentage of steel confinement

0

0.79

1.06

1.32

1.82

2.43

3.04

1

0%-GGBS

M2S

M2S1

M2S2

M2S3

M2S4

M2S5

M2S6

2

30%-GGBS

M2SG

M2SG1

M2SG2

M2SG3

M2SG4

M2SG5

M2SG6

3

3%-RHA (GGBS replaced with RHA )

M2SGR

M2SGR1

M2SGR2

M2SGR3

M2SGR4

M2SGR5

M2SGR6

Fig.1.8.1. Stress-Strain behaviour M2S, M2S1, M2S2,

M2S3, M2S4, M2S5, M2S6 Mixes

1.8.2 Models for Stress-Strain Behaviour of SCC Mixes

An examination of the stress-strain curves indicates that, the

behaviour is similar for all the specimens with and without steel. The

only a difference is that the SCC mixes with steel confinement have

13

shown improved stress values for the same strain levels compared to that

of SCC mixes. The similarity leads to the conclusion that there is only a

unique shape of the stress-strain diagram, if expressed in a non

dimensional form, along both the axes. The said form can be obtained by

dividing the stress at any level by peak stress and the strain at any level

by peak strain. Thus all the stress-strain curves will have same point

(1,1) at peak stress. By non- dimensionalising the stresses and strains as

above, the behaviour can be represented as a general behavior. The

stress-strain curves obtained experimentally for SCC with and without

steel were normalised as specified above and normalised stress-strain

values were calculated for all SCC mixes.

Of all the eight SCC mixes with different mineral admixtures taken for

investigation, the normalised stress-strain curves for different grades

SCC are developed and for M20 GGBS mix curve is shown in figure

1.8.2, whereas M40 and M60 curves are plotted and presented in main

thesis.

Fig.1.8.2. Normalised Stress-Strain behaviour of M20-GGBS

14

The developed normalized stress-strain curves are fitted with analytical

equations using Seanz‟s model. The developed equations are in the

form of Y = Ax/ (1+Bx2) where x - is the normalized strain which is

Є / Є0 and Y- Normalized stress which is σ /σ0. A, B and A1, B1 are a

set of constants for ascending and descending portions of SCC.

Analytical Equations for SCC Mixes

The equations for ascending and descending portions of mixes are

Mix Constants for

ascending portion Constants for

descending portion

M20SCC mix A = 1.44, B = 0.53 A1 = 1.49, B1=0.71

M20 GGBS mix A = 1.53, B = 0.37 A1=2.00, B1= 1.20

M20 GGBS-RHA mix A=1.20, B = 0.37 A1=1.29, B1=1.22

M40 SCC mix A=1.25, B = 0.58 A1=2.56, B1=1.77

M40 GGBS mix A=1.25, B = 0.27 A1=2.42, B1= 1.62

M40 GGBS-RHA mix A=1.09, B = 0.22 A1=2.08, B1=1.30

M60 SCC mix A=1.41, B = 1.00 A1=2.27, B1=1.47

M60 GGBS-RHA mix A=1.64, B = 0.33 A1=2.59, B1= 1.80

Mix Equations for

ascending portion Equations for

descending portion

M20SCC mix Y = 1.44 x/ (1+ 0.53 x2) Y = 1.49 x/ (1+0.71x2)

M20 GGBS mix Y = 1.53 x/ (1+0.37 x2) Y = 2.0 x/ (1+1.20 x2)

M20 GGBS-RHA mix Y = 1.20 x/(1+0.37 x2) Y = 1.29 x/ (1+1.22 x2)

M40 SCC mix Y = 1.25 x/ (1+ 0.58 x2) Y = 2.56 x/ (1+1.77 x2)

M40 GGBS mix Y = 1.25 x / (1+0.27 x2) Y = 2.42 x/ (1+1.62 x2)

M40 GGBS-RHA mix Y = 1.09 x/ (1+0.22 x2) Y = 2.08 x/ (1+1.30 x2)

M60 SCC mix Y =1.41 x/ (1+1.0 x2) Y = 2.27 x/ (1+1.47 x2)

M60 GGBS-RHA mix Y = 1.64 x/ (1+0.33 x2) Y = 2.59 x/ (1+1.80 x2)

15

The proposed analytical equations can be used as stress block in

analysing the flexural behavior of sections of SCC structural elements.

1.8.3 Development of Theoretical Stress-Strain Curves

From the developed analytical equations for the stress-strain

behaviour of SCC with and without steel confinement, stress values at

different strain levels for all SCC mixes were calculated. Stress-strain

curves are plotted with these values and compared with the

experimental stress-strain curves which show good correlation. An

experimental and theoretical stress-strain curve of M2S4 mix is shown

in figure 1.8.3.

Fig-1.8.3. Experimental & Theoretical Stress-Strain -M2S4

1.9. STUDIES ON FLEXURAL BEHAVIOUR OF SCC MIXES

Sixteen simply supported beams consisting of eight under reinforced

and eight over reinforced were cast and tested under third point loading.

Its load-deflection, moment curvature behaviour along with crack widths,

load at first crack, ultimate load carrying capacities and crack pattern for

16

under reinforced, over reinforced beams were investigated. A load-

deflection plot is shown in figure1.9.1. Theoretically the moment-

curvature relationships were developed using analytical equations for

stress-strain behaviour of SCC and were compared with the experimental

moment-curvature relationships for different SCC mixes.

Fig.1.9.1. Load-deflection plots for over -reinforced beams

1.10. DEVELOPMENT OF MOMENT-CURVATURE RELATIONSHIPS

USING ANALYTICAL MODELS.

The analytical models proposed for stress-strain behaviour of SCC with

confinement are used as the basis for prediction of the analytical

behaviour of moment-curvature. The moment of resistance offered by the

concrete (Mc) can be determined by Mc = b (nd/Є) 2 ∫ σ Є dε

Where σ = A1 Є and

(1+B1Є2)

∫ σ Єdε = A1 Є – A1 Tan-1 √B1 Є

B1 B1√B1

17

As two separate equations are proposed for ascending and descending

portions of the stress-strain curve

Є0 Є0.85

Mc = b (nd /Є) 2 ∫ σ1 Є dε + ∫ σ 2 Є dε }

0 Є0

The moment of resistance offered by steel (Ms) can be determined by

Ms = Ts (d-nd) = σst x Ast (d-nd)

Knowing the values of Є and n, theoretical curvature (Ф) can be

determined using the relationship Ф = (Є/nd). Using the above developed

procedure the moment-curvature relationships are plotted as shown in

the fig 1.10.1

Fig.1.10.1 Experimental and Theoretical M-Ф plots for

Beam UR & OR of M2S-mix

18

1.11 DURABILITY STUDIES OF LOW, MEDIUM AND HIGH GRADE

SCC MIXES WITH GGBS AND RHA.

Apart from strength studies a detailed experimental investigation is done

on the acid durability of self-compacting concrete (SCC) prepared with

and without admixtures. The cubes are immersed for30 days, 45days, 60

days, 75 days and 90 days in Sulphuric acid (H2SO4), Sodium Sulphate

(Na2SO4) and Hydrochloric acid (HCl) solutions separately. Weight and

compressive strength losses, ADF & AAF are the main properties

investigated. The table 1.11.1 shows the Acid durability and Acid attack

factors for M20 SCC mixes and the fig.1.11.1 shows the graph between

acid durability factor and days of immersion in H2SO4.

Table 1.11.1 Acid Durability & Acid Attack Factors for different SCC Mixes

No. of

days of

immersion

Immersion in H2SO4

M20 M20 GGBS M20 GGBS- RHA

Sr ADF AAF Sr ADF AAF Sr ADF AAF

30 98.65 32.88 0.35 98.78 32.92 0.29 99.00 33.00 0.21

45 94.78 47.39 0.71 96.85 48.43 0.46 97.70 48.85 0.35

60 90.51 60.34 1.53 94.87 63.24 0.91 95.48 63.65 0.95

75 85.80 71.50 2.89 91.81 76.50 1.85 94.70 78.92 1.42

90 83.57 83.57 2.91 89.60 89.60 2.58 93.60 93.60 1.98

Sr - Relative Strength, Acid Durability Factors - ADF, Acid Attack Factors - AAF.

19

Fig.1.11.1 Acid Durability Factor and Days of immersion of

M20 grade SCC mixes in H2SO4 Acid

1.12 CONCLUSIONS

1. The addition of RHA to GGBS mixes has shown improved performance

in terms of strength and durability in all grades of SCC.This is due to

the presence of highly reactive silica in GGBS and RHA.

2. Studies indicated that there is a good compatibility between mineral

combinations GGBS and RHA along with the chemical admixtures

such as SP and VMA when used in SCC.

3. The Bolomey‟s empirical expression can be used to predict the

strength efficiency of the GGBS and RHA in SCC at different

percentage of replacement levels.

4. The strength efficiency factor „k‟ of GGBS in SCC mixes at 28 days

was found to be between 0.7 to 1.8. The strength efficiency factor k for

normal concrete mixes were reported to be between 0.7 to 1.3 by

20

K.Ganesh Babu and V.Sree Rama Kumar [37],which shows the

strength efficiency factors are slightly higher for SCC mixes with

GGBS.

5. Similarly experimental studies on efficiency of GGBS and RHA

combination in SCC confirmed the enhanced performance in terms of

both strength and durability aspects with respect to performance of

GGBS alone in SCC.

6. Based on the stress-strain curves of SCC mixes with and without steel

confinement it is observed that the stress-strain pattern is to be

almost similar. But the GGBS-RHA mixes have shown improved

stress values. It is observed that for higher grades of concrete with

increase in stress there was decrease in strain.

7. Empirical equations for the stress-strain response of SCC mixes

have been proposed in the form of Y = Ax/ (1+Bx2), where x is

normalized strain and Y is normalized stress. The same empirical

formula is valid for both ascending and descending portions with

different values of constants.

8. It is observed that there is an increase in the peak compressive

strength for different SCC mixes made with GGBS and RHA mixes.

The increase is due to high reactivity of RHA with GGBS

9. Addition of GGBS and RHA control the initiation of micro cracks,

improve the first crack load, the ultimate load and ductility of SCC

21

specimens under flexure. They are also effective in resisting

deformation at all stages of loading from first crack to failure.

10. Load deflection behaviour for all SCC beams is observed to be similar

except the increased values of loads at ultimate and at first crack due

to addition of GGBS and RHA to SCC mixes.

11. Theoretical moment-curvature relationships for SCC and beams

followed similar pattern as that of experimental values. The only

difference noticed is the values of theoretical moments calculated are

lesser than the experimental values. But the variation is very less,

thus theoretical values of moments almost coincide with experimental

values. This shows a good correlation between them.

12. The Acid durability factors (ADF) were found to be more in SCC made

with GGBS and RHA in three grades. The Acid Attack Factors (AAF)

has shown that the GGBS and RHA mixes are more resistant for acid

attack.

13. The strength loss and weight loss observed to be less in mixes with

GGBS and RHA.

1.13. SOME IMPORTANT REFERENCES

1. Ahmadi, Alidoust “Development of Mechanical Properties of SCC

containing Rice Husk Ash” Proceedings of World Academy of Science,

Engineering and Technology Volume 23 August 2007 .

22

2.AnniePeter.J,Lakshmanan.N, Devadas Manoharan.P, Rajamane.N.P&

Gopalakrishnan.S “Flexural Behaviour Of RC Beams Using Self

Compacting Concrete”. The Indian Concrete Journal, June 2004, PP

66-72.

3. D.R.Seshu & K.Ramesh “Constitutive behaviour of confined fibre

reinforced concrete under axial compression” cement and concrete

composites, 2003, pp 343-350.

4. K.Ganesh Babu and V. Sree Rama Kumar, “Efficiency of GGBS in

concrete”, Cement and Concrete Research Volume 30, Issue 7, July

2000, Pages 1031-1036.

5. Mehta. P.K., “Properties of Blended Cements made from Rice Husk

Ash”, American Concrete Institute Journal, Sept. 1977.

6. Nan Su, Kung-Chung Hsu, His-Wen Chai “A simple mix design

method for self-compacting concrete” Cement and Concrete

Research 31 (2001) 1799–1807.

7. N.R.D. Murthy, D.R.Seshu and M.V.S.Rao, “Constitutive behaviour

of fly ash concrete with steel fibres in ordinary grade” IE (I) Journal-

CV, Aug 2007,pp41-46.

8. Okamura Hajime & Ouchi Masahiro “Self Compacting Concrete”.

Journal of Advanced Concrete Technology, Vol 1, April 2003, pp 5-14.

23

9. Okamura, H. and Ouchi, M. "Effect of super plasticizer on self-

compactability of fresh concrete," Transportation Research Record,

No.1574, Dec.1997, pp.37-40.

10. Pap worth,F. and Radcliffe, R. (1994), “High-Performance Concrete-

the concrete future”, Concrete International, V. 16, No. 10, pp. 39-44.

11. Ravindra Gettu “Application of Self-Compacting Concrete: Recent

experience and challenges that remain” Proceedings of International

Conference on Advances in Concrete & Construction,ICACC-2008, 7-9

Feb., 2008, Hyderabad, pp 58-71.

12.Seshagiri Rao.M.V., Janardhana.M. Rao.K.R.M, Ravindra Kumar.

“High ly Ash Concrete with RHA as an admixture.1999.Vol.80.Journal

of Institution of Engineers, (India).pp.57-63.

13. Seshagiri Rao.M.V and Rama Rao.G.V. “High performance RHA fiber

reinforced concrete with chicken mesh wire fibers”. Proceedings of the

International Conference on Recent Trends in Concrete Technology

and Structures.Coimbatore.2003, pp 381-393.

14. SureshBabu.T“Mechanical properties and stress- strain behaviour

of self compacting concrete with and without glass fibres” Asian

journal of civil engineering (building and housing) vol. 9, no. 5 (2008)

pages 457-472.

15.“The European Guidelines for Self Compacting Concrete

Specification, Production and Use” Feb 2002 and May 2005.

24

LIST OF PUBLICATIONS OF THE AUTHOR RELATED TO THE

PRESENT WORK

NATIONAL JOURNALS (PUBLISHED)

1. “Utilization of Solid Waste Material in Self Compacting Concrete.”

Environmental Pollution Control Journal Vol 13, No.1 (2009) pages 44-47.

2. “Study on the Strength Characteristics of SCC with GGBS and RHA as

mineral admixtures” The IUP Journal of Structural Engineering Vol.III No 3,

July 2010 pages 35-46.

INTERNATIONAL CONFERENCES

1. “Strength Characteristics of High Volume Fly Ash Concrete”

ICCE-2001, 23-25 July 2008, pp 120-125, International Conference on

Civil Engineering held by Department of Civil Engineering, IISC Bangalore.

2. “Study of Low Medium and High Strength Self Compacting Concrete with

different Admixtures as Replacement of Cement.” accepted for 7th

International Symposium on Cement & Concrete, ISCC-2010 and the

International Conference on Advance in Concrete Technology and

Sustainable Development, May 9-12, 2010, in Jinan, P. R. China

NATIONAL CONFERENCES

1. “Impact of Concrete Materials on Climate and its Management” Proceedings

of National Conference on “Climate Change Abatement: Role of Civil

Engineers”, 23rd and 24th October, 2009, Institution of Engineers (India), A P.

pp 77-81.