16

2.0 REVIEW OF LITERATURE

2.1 GENERAL

Many Researchers have studied the effect of replacement of

Portland cement by Metakaolin and also on fibre addition on the

mechanical and durability properties of ordinary Portland cement

concrete. The literature being reviewed is given under four sections.

(1) Review of literature of concrete containing pozzolanic materials

such as Metakaolin.

(2) Review of literature of SFRC on workability, compressive

strength, tensile strength and modulus of elasticity.

(3) Review of literature of SFRC on impact resistance.

(4) Review of literature of OPCC, MKC & SFRC on exposure to

elevated temperatures.

(5) Review of literature of OPCC on compressive strength, split

tensile strength, flexural strength and modulus of elasticity when

exposed to different thermal cycles.

2.2 REVIEW OF LITERATURE OF CONCRETE

CONTAINING POZZOLANIC MATERIALS SUCH AS SILICA

FUME AND METAKAOLIN

Yogendran et al. (1987)19 made an attempt to modify the properties

of concrete with respect to its strength and other properties by using

silica fume and chemical admixtures. They concluded that optimum

replacement of cement by silica fume for high strength is found to be

15% for a water cementatious ratio of 0.34 at all age.

17

Alhozaimy, A.M., et al (1995)37 carried out experimental

investigations on the effects of adding low volume fractions (<0.3%) of

calculated fibrillated polypropylene fibres in concrete on compressive

flexural and impact strength with different binder compositions. They

observed that polypropylene fibres have no significant effect on

compressive (or) flexural strength, while flexural toughness and

impact resistance showed increased values. They also observed that

positive interactions were also detected between fibres and pozzolans.

F.Curcio, B.A. De Angelis, and S.Pagaliolico (1998)43 in their

investigation, super-plasticized mortars containing Metakaolin (MK) as

15% replacement of cement and with a water/binder ratio of 0.33

have been characterized with four commercially available MK samples

have been studied and compared to silica fume. Three out of four

Metakaolin samples showed improvement in compressive strength at

early ages, when compared to SF, but at 90 days and later the

difference is reduced. The difference in the compressive strength

between the specimens with micro fillers and the control decreases

after 28 days, because of a smaller slow down of the hydration rate in

the control. This can be related to the fineness of the micro-filler in

the specimens with Metakaolin. At 90 and 180 days Metakaolin and

silica fume specimens gave similar strengths.

F.Curcio and B.A. De Angelis (1998)44 in their investigation, cement

pastes containing Metakaolin have been studied with a co-axial

cylinder rotational viscometer. They show a dilatent behavior that is

strongly dependent on the water /binder ratio, on the level of cement

18

replacement by Metakaolin and on the fineness of the latter.

Dilatency is caused by the angular and plate like shape of Metakaolin

particles. They concluded that, dilatancy is governed by water to

binder ratio, amount of Metakaolin and its fineness. Finally, the

dilatant properties can be explained by considering the plate like and

angular shape of MK particles in comparison with SF.

Handong yan, Wei Sun, Husiu chen (1999)45 in their investigation,

the impact and fatigue performance of high-strength concrete (HSC),

silica fume high-strength concrete (SIFUHSC), steel fibre high strength

concrete (SFR HSC), and steel fibre silica fume high-strength concrete

(SSF HSC) under the action of repeated dynamic loading were studied.

The mechanisms by which silica fume and steel fibres, reduce the

damage were investigated.

The results indicate that, steel fibre effectively restrained the

invitation and propagation of cracks during the failure. The presence

of steel fibres in high strength concrete was effective in restoring the

structure under fatigue and impact by delaying the damage process.

Silica fume effectively improved the structure of the inter-face,

eliminated the weakness of the interfacial zone, reduced the number

and size of cracks, and enhanced the ability of steel fibres to resist

cracking and restrain damage. As a result, the incorporation of steel

fibres and silica fume can together increase greatly one performance of

HSC subjected to impact and fatigues. The filler effect of silica fume

can reduce the number and size of the original cracks in the

interfacial zone and in the bulk of concrete and enhanced the

19

interfacial effect. Steel fibres mainly strengthen, toughen and resist

cracking in HSC.

J.M. Kinuthia et al. (1999)46 An experimental investigation is made

by the authors in studying the workability of concrete incorporating

combinations of pulverized fuel ash (PFA) and Metakaolin (MK) as

partial replacements for Portland cement (PC). The aim of the

research work is to explore the potential of using PFA and MK as

blends with PC in terms of the flow properties of the resulting

concrete. Mixtures containing 0, 10, 20, 30 and 40% total

replacement of cement with combinations of Metakaolin (0-15%) and

PFA (0-40% for concretes with water-to-binders ratios of 0.4, 0.5 and

0.6 were prepared. Workability of the concrete was measured by the

slump, compacting factor and vee-bee time tests. The following

conclusions are made by the authors.

i). The workability of PC-MK concrete is substantially reduced with an

increase in MK content. The workability reduction caused by MK is

attributed to its high chemical activity and high specific surface,

resulting in increased intake and hence greater water requirement.

The influence of MK on compaction and flow is reduced to the

thixotropic nature of clay suspension and to a reduction of void space

due to the improved dispersal of the MK particles.

ii). The workability of PC-PFA concrete without super plasticizer

increases significantly with increase in PFA content. For PFA contents

above 10% PFA workability falls. The reduction in workability is

attributed to flocculation/coagulation at low PFA concentration and

20

the increase in workability at high concentration is attributed to

neutralization of positive charges on cement particles and their

resultant dispersal. When super plasticizer is used as a dispersing

agent, no fall in workability is observed.

iii). Loss of workability due to the present of MK can be compensated

for by the incorporation of PFA. The degree of restoration of

workability, provided by PFA, is influenced significantly by the cement

replacement level, the MK/PFA ratio and the W/b ratio-dispersed

mixture is a critical MK/PFA ratio at which the loss in workability

imparted by the MK is exactly compensated for by the gain in

workability imparted by the PFA.

Kinuthia J.M. et al (2000)48 The contribution by the authors in this

paper forms a part of an ongoing investigation examining the potential

of using Metakaolin, pulverized fuel ash (MK-PFA) blended for cements

in concrete. The investigation involves the examination of the effect of

the blends on the strength development and factors affecting

durability including chloride penetration, carbonation and water

transport properties. The following conclusions were made by the

authors:

i) Although the early compressive strength of concrete is reduced by

the incorporation of PFA as a partial replacement for cement,

pozzolanic action develops in the medium term and up to 30% PFA

may be used without detriment to the strength at 90 days. PFA is

particularly effective in this respect at the moderately low water-to-

binder ratios of 0.4 and 0.5.

21

ii) Up to 15% partial cement replacement by Metakaolin results in

considerable enhancement in strength in both the short and the

medium term. The strength enhancement is obtained for all the water

to binder ratios used (0.4-0.6).

iii) The contrasting roles played by PFA and Metakaolin in the

strength development, particularly at the early stages, can be

compared to produce effective blends for cement. At short curing

times, only mixtures with low PC replacement levels and high MK/PFA

ratios achieve strength in excess of the control. However, after 90

days curing, mixtures with high PC replacement levels and low

MK/PFA ratios also achieve strengths in excess of the control.

iv) The incorporation of small quantities of PFA, as partial cement

replacement, results in an acceleration of PC hydration, which in turn

gives rise to increased strength.

M.Frias, M.I.Sanchez derojas, J.Cabrera (2000)49 In their

experimental work, the influence of the pozzolanic activity of the

Metakaolin(MK) on the hydration heat has been studied in comparison

to the behaviors of other traditional pozzolanic materials such as

flyash and silica fume. The results revealed that MK mortars produce

a slight heating increase when compared to a 100% Portland cement

mortar, due to the high pozzolanic activity of MK. With respect to the

hydration heat, MK-blended mortar showed closer behaviors to silica

fume than to fly ash.

Moises Frais, Joseph Cabrera. (2000)50 the authors shows the

results of an investigation focusing on the effect of Metakaolin (MK) on

22

the micro-structure of MK-blended pastes. Pastes containing 0%,

10%, 15%, 20% and 25% of MK were prepared at a constant

water/binder ratio of 0.55 and cured at 200c for hydration periods

from 1 to 360 days. They investigated total capillary and gel porosity

evolution with the curing period and also estimated the degree of

hydration in the ordinary Portland cement and Metakaolin blended

pastes. The values of the degree of hydration are calculated from the

amount of Ca(OH)2 present in the paste and from the data of

differential thermal analysis (DTA) thermogravimetry (TG). A good

association between porosity and degree of hydration has been

established.

The total porosity decreases up to 28-56 days of curing time.

They observed that, up to 28 to 56 days of curing the porosity is same

for all the mixes. Beyond 56 days the porosity of all the Metakaolin

mixes increasing when compared with OPC mix. Similar phenomenon

is observed for capillary porosity. The best evidence of the influence of

MK on the refineness of the pore structure was detected in pores with

radius smaller than 100 0A. Between 7-90 days, the gel porosity of MK

mixes increase, while the OPC mix remains practically constant. The

results show the necessity of obtaining important improvement in the

porosity reducing the average pore diameter and gel porosity.

Measured lime contents show the total consumption of MK (10% to

15%) at 90 days of hydration time. A good statistical relationship has

been found between the degree of hydration and the porosity.

23

Brooks et.al. (2000)51 after studying the effect of silica fume,

Metakaolin, fly ash and ground granulated blast furnace slag on

setting times of high strength concrete, they concluded that there was

increase in the retarding effect up to 10% replacement of cement by

Metakaolin and as the percentage replacement is increased, the

retarding effect is reduced.

Shannag (2000)52 designed and studied very high compressive

strength of 69 to 110 MPa along with incorporation of locally available

natural pozzolana and silica fume. He concluded that 15%

replacement of cement with silica fume along with 15% natural

pozzolan gave relatively higher strength than without natural

pozzolan.

A.Shvarzman, K.Kovler, G.S.Grader G.E.Shter (2001)54 The effect of

heat treatment parameters on the dehydroxylation/amorphization

process of the kaolinite based materials such as natural and artificial

kaolin clays with different amounts of amorphous phase (Metakaolin)

was investigated by the above authors. The process of

dehydroxylation/amorphization of kaolinite were characterized by

DTA/TGA with mass-spectrometry and x-ray power diffraction. The

influence of the heat treatment, temperature and content of the

amorphization phase on pozzolanic activity was studied. The results

obtained are important for an optimization of the process of the

Metakaolin large scale production and its use as a pozzolanic

admixture.

24

At the calcination temperature below 4500C kaolin clays show

relatively low level of the dehydroxylation degree, less than 0.18. In

the range from 4500C to 5700C, the degree of dehydroxylation sharply

increased to 0.95, and finally at the temperature range between 570

and 7000C the kaolinite was fully dehydroxylated since the only

moderate change of degree of dehydroxylation was observed in this

range (from 0.95 to 1.0). It was found that the dehydroxylation is

accompanied with the kaolinite amorphization which affects the

activity of additives. A method of qualitative evaluation of amorphous

phase content (APC) in treated materials was developed and applied

for characterization of the investigated samples. Therefore, even with

the partial dehydroxylation of kaolinite accompanied with

approximately 55% ammorphization, the material may be considered

as very active pozzolanic admixture (according to ASTM 618). This

finding seems to be extremely important for reduced energy demand

during the production of Metakaolin.

K.A.Gruber, Terry Ramlochan, AndreaBoddy, R.D.Hooton,

M.D.A.Thomas (2001)55

The investigations carried out by the above authors revealed

that the temperature rise in MK-PC mortars (above 5% MK and up to

at least 15% MK) is greater than that in equivalent PC mortar (other

than at very low MK levels). The increase in heat evolution during

initial hours of hydration was resulted from the combined effect of

accelerated Portland cement hydration and pozzolanic reaction. The

temperature rise in PFA-PC mortars is less than that in equivalent PC

25

mortars, this is attributed to the dilution of the PC by the PFA coupled

with the latter‟s negligible pozzolanic activity during the reaction, both

the rate of heat evolution and the total heat evolved.

Xia Oquian and Zongjinli (2001)56 studied the stress–strain

relationships of concrete containing 0% to 15% of Metakaolin at an

incremental rate of 5%. They concluded that incorporation of

Metakaolin up to 15% has increased the tensile and compressive

strength and also peak strain is increased at increasing rate of

Metakaolin up to 15%. Incorporation of Metakaolin has slightly

increased the compressive elasticity modulus.

Poon et al (2001)57 investigated the rate of pozzolanic reaction of

Meta kaolin in high performance cement mortars. They studied the

hydration progress of Metakaolin in terms of its compressive strength,

porosity and pore size distribution. They concluded that the higher

pozzolanic reactivity results in a higher rate on strength development

and its pore structure refinement for the cement pastes at earlier

ages.

W.Aquino, D.A.Lange, J.Olek (2001)58 Attempt is made by the

authors to study the influence of SF (Silica Fume) and HRM (High

Reactivity Metakaolin) on the chemistry of ASR (Alkali Silica reaction)

products. They observed that silica fume and high reactivity

Metakaolin reduce expansion due to ASR. Also they observed that the

calcium content of ASR products is increasing with time in all the

samples without mineral admixtures and a lower level of calcium was

detected in samples containing mineral admixtures. In addition, X-

26

ray micro-analysis showed that calcium content increases with time in

ASR products. It was found that as ASR reaction proceeds, the

calcium to silica reaction of the reaction products increases following

a linear trend. From the results it is suggested that calcium in gel

products may be responsible for expansion.

D.M.Roy, P.Arjunan, M.R.Silsbee (2001)60 In their investigation,

effects of aggressive chemical environments were evaluated on the

mortars prepared with low-calcium fly ash/Metakaolin (MK)/silica

fume (SF)/ordinary Portland cement (OPC) and at various replacement

levels. The natural adverse chemical environmental conditions were

simulated using sulphuric acid, hydrochloric acid, nitric acid, acetic

acid, phosphoric acid and a mixture of sodium and magnesium

sulphates. They proposed resistance of the above mortars against the

chemical environment was in concurrence with compressive strength

measurements.

The results show some interesting trends with respect to acid

resistance. Substitution of SF, MK, or FA under certain conditions

has been shown to increase the chemical resistance of such mortars

over those with plain Portland cement. The mortar made from all three

series showed poor resistance to higher acid concentrations of 5%

sulphuric acid, 5% acetic acid, and 5% phosphoric acid environments.

Chemical resistance increased in the order of SF to MK to FA series

and decreased as the replacement level is increased from 0-10%

weight replacement level to 15-30% weight level. They observed that

27

compressive strength is increasing in the order of fly ash to Silica

fume to Metakaolin.

Megat Johari M.A. et al. (2001)61 In their investigation, the effect of

Metakaolin (MK) on the creep and shrinkage of concrete mixes

containing 0%, 5%, 10% and 15% MK has been studied. The

outcomes showed that autogenous shrinkage measured from the time

of initial set at the early age of the concrete was decreased with the

inclusion of MK, but the long – term autogenous shrinkage measured

for the age of 24 hrs was increased at 5% replacement level, the effect

of Metakaolin has increased the total autogenous shrinkage

considering from the time of initial set. While at replacement levels of

10% and 15% it reduced the total autogenous shrinkage. The total

shrinkage (autogenous plus drying shrinkage) measured from 24 hrs

was reduced by the use of MK, while drying shrinkage was

significantly less for the MK concrete than for the control concrete.

At higher Metakaolin replacement levels, the total creep, basic creep

as well as drying creep was significantly reduced. On overall,

compared with the control concrete, the greater part of the total

shrinkage of the MK concrete is constituted by autogenous shrinkage,

the smaller part being drying shrinkage. Particularly at higher

Metakaolin replacement levels, drying creep, basic creep and total

creep were greatly reduced.

Jamal M.Khatib, Roger M.Clay (2003)74 in their investigation, the

water absorption (WA) by total immersion and by capillary rise of

concrete containing Metakaolin (MK) is studied. Cement was partially

28

replaced with up to 20% MK. The results show that the presence of

Metakaolin is greatly beneficial in reducing the water absorption by

capillary action. There is a systematic reduction in water absorption

by capillary action with the increase in Metakaolin content in

concrete. Between 14 and 28 days curing, there is slight increase in

absorption by total immersion and by capillary rise for all MK

concretes.

The partial replacement of cement with MK reduces the water

penetration in to concrete by capillary action. The water absorption of

concrete by total immersion, however is slightly increased in concrete

containing Metakaolin. WA decreases with duration of curing for all

MK concretes up to 14 days. Between 14 and 28 days of curing, there

is a slight increase in water absorption. After 28 days of curing there

is little change in WA. An increase in the total pore volume leads to

an increase in water absorption.

Sabir, B.B. et al (2002)66 The authors reports the influence of the

composition of Portland cement, pulverized fuel ash and Metakaolin

(PC-PFA-MK) binders on sorptivity and strength development of

Portland Cement – Pulverised Fuel Ash - Metakaolin concrete cured

both in water and in air and on carbonation depth, and relates this to

measured changes in absorptivity of the concrete. Concrete mixtures

covering four different total cement replacement levels (10%, 20%,

30% and 40%) for PC-PFA-MK concrete with various MK/PFA

proportions, water and air cured for upto 18 months were

investigated. The change in compressive strength and absorptivity

29

with age at all cement replacement levels under both water and air

curing are compared with those of the control Portland cement

concrete. The results presented in this paper from part of an

investigation in to the optimization of a ternary blended cementitious

system based on ordinary Portland cement, Pulverised Fuel Ash and

Metakaolin for the development of HPC. Increasing replacement of PC

with PFA in PC-PFA air (CO2 enriched) cured concrete increases

carbonation depth where as systematically replacing the PFA with MK

in PC-PFA-MK concrete reduces carbonation depth.

Jain-Tong Ding and Zongjinli (2002)65 investigated the properties of

concrete by incorporating 0% to 15% cement replacement by

Metakaolin (or) silica fume. They concluded that by incorporation of

Metakaolin and silica fume, they can reduce the free drying shrinkage

and restrained shrinkage cracking width. Also they can reduce the

chloride diffusion rate significantly.

Luccourard et al. (2003)73 studied the durability of mortars

containing Metakaolin. The studies on transport and chemical

behaviors by means of chloride diffusion tests and sulfate immersion

were carried out. They concluded that 10% to 15% replacement of

cement by Metakaolin lead to low decrease of workability and best

mechanical performance and inhibition effect on chloride diffusion

and sulfate attack for 20% Metakaolin.

T.Ramlochan, et al. (2003)67 the expansive behaviors of heat cured

mortars containing pozzolans and slag was investigated by the

authors. In almost all the mortars, the addition of any amount of

30

pozzolans and slag to the mixture usually reduced the onset of

expansion, the rate of expansion, and long-term expansion. However,

the efficiency of a particular pozzolan (or) slag in controlling expansion

may depend on its Al2O3 content. Metakaolin, which contains a

higher amount of reactive Al2O3, was the most effective at controlling

expansion at relatively low cement replacement levels. Slag and fly

ash which are also sources of Al2O3 were also effective at suppressing

expansion at higher replacement levels. Silica fume was less effective

at controlling expansion at conventional replacement levels, and even

at higher replacement levels expansion may be delayed.

Zongjin Li, Zhu Ding (2003)68 in their investigation, the physical

and mechanical properties of Portland cement (PC) containing

Metakaolin (MK) or combination of MK and slag and the compatibility

between such materials and super-plasticizers were studied. The

following conclusions are made by the authors:

MK is a new active mineral admixture used in cement concrete

products. It has a positive effect on the mechanical properties of

cement. However, MK blended cement has a poorer fluidity compared

to Portland cement under the condition which used the same amount

of super plasticizer. By the addition of ultra fine slag this can be

improved. By incorporating 10% MK and 20% (or) 30% ultra-fine slag

jointly into PC, not only the fluidity of blended cements was improved,

but above the 28-day compressive strength of the cements was

enhanced. Metakaolin is a high active pozzolanic mineral admixture.

The formula can prompt the hydration of PC, shorten the setting time

31

of cement, increase the water requirement and increase the fluidity

losing of the fresh paste. However, slag can delay the reaction of

cement hydration and prolong the setting time of cement paste. Both

MK and slag can react with CH released by cement clinker hydration

to produce secondary C-S-H gel inside the cement paste matrix.

Therefore the macroscopic property of cement was improved. XRD

analysis indicates that more Calcium Hydroxide was consumed after

adding both mineral admixtures.

Jamal Khatib and Roger (2003)74 investigated the water absorption

by total immersion and by capillary rise of concrete containing

Metakaolin up to 20% replacement level. They concluded that water

absorption of curing for all Metakaolin concretes up to 14 days and

between 14 and 28 days of curing there is a small variation in

absorption.

E.Badogiannis, V.G.Papadakis, E.Chaniotakis, S.Tsivilis (2004)82

in their investigation, the effect of Metakaolin on concrete, kaolin was

thermally treated at defined conditions, and the produced Metakaolin

was superfine ground. For comparison, a commercial MK of high

purity was used and the strength development of Metakaolin concrete

was evaluated using the K - value (efficiency factor). The produced

Metakaolin as well as the commercial one imparted similar behaviour

with respect to the concrete strength. Both conventional and

commercial Metakaolins demonstrate very high K-values (close to 3.0

at 28 days) and are depicted as HR pozzolanic materials that may lead

towards concrete production with an exceptional performance.

32

Juenger et al. (2004)85 studied the alkali-silica reactivity of large

silica fume derived particles. They reported that under accelerated

testing agglomerated silica fume decrease expansion when used as a

5% replacement of reactive sand.

Fabien Lagier, Kimberly E.Kurtis (2007)93 in their investigation, the

research on two Metakaolins which vary principally in their surface

area, and Portland cements of varying composition were examined via

isothermal calorimetry for pastes at water cementitious materials ratio

of 0.50 containing 8% cement replacement by weight of Metakaolin.

The following preliminary conclusions are made by the authors:

i). The Metakaolins examined appear to have a catalyzing effect on

cement hydration, leading to acceleration in the reaction rates, an

increased in cumulative heat evolved during early hydration and for

some cements apparently an increased intensity in heat evolved

during certain periods of each hydration. The surface area of the

Metakaolin also seems to influence these early hydration behaviors,

with the higher surface area material producing a greater rate of heat

evolution, greater cumulative heat, and greater intensity during early

hydration. It is proposed that the Metakaolin may act to enhance

dissolution of cementitious phases and or by providing nucleation, in

addition to increasing the solubilized aluminium in the system at early

ages.

ii). Strongly exothermic reactions appear to occur between the

cements and Metakaolin examined, particulars in the first 24 hours,

and these reactions seem to be most closely allied with the “Third

33

Peak” experiential in calorimetry related to the reaction of calcium

aluminate phases.

iii). The reaction of MK appears to be quite sensitive to variation in

total alkali content in the cement. When the alkali content increases

the beginning of MK appears to result in amplification of the third

peak viewed during calorimetry. It is proposed that an increasing rate

of Metakaolin dissolution with increasing cement alkali-content may

accelerate (or) intensify the reaction of C3A phase.

David G. Snelson et al. (2008)94 investigated the effect of using

Metakaolin and flyash as partial replacements with cement on the rate

of heat evolution during hydration. It was observed that adding flyash

to Portland cement enhanced the Portland cement hydration in the

very early stages of hydration, but at extended periods an increase in

flyash replacement causes a systematic reduction in heat output.

When combining Metakaolin and flyash in ternary blending, the

Metakaolin has a dominant influence on the heat output versus time

profiles.

2.3 REVIEW OF LITERATURE OF SFRC ON

WORKABILITY, COMPRESSIVE STRENGTH, TENSILE

STRENGTH AND MODULUS OF ELASTICITY

Romualdi and Batson (1963)1 after conducting impact test on fibre

reinforced concrete specimens, they concluded that first crack

strength improved by addition of closely spaced continuous steel

fibres in it. The steel fibres prevent the adverting of micro cracks by

34

applying pinching forces at the crack tips and thus delaying the

propagation of the cracks. Further, they established that the increase

in strength of concrete is inversely proportional to the square root of

the wire spacing.

Sridhara, S., et al. (1971)2 carried out experimental investigations to

study the blast resistance of concrete, by adding different types of

fibres like, nylon, coir and Jute at various percentages by volume of

concrete. They concluded that fibres increased the impact and shatter

resistance of concrete. Out of nylon fibres even at low fibre contents

found to be the most effective reinforcement for increasing the impact

strength of the concrete.

Jack Synder and David hankard (1972)3 investigated mortars and

concrete by reinforcing small short steel fibres in flexure. They

concluded that there is significant increase in the first crack strength

and ultimate strength. Due to addition of coarse aggregate to a

reinforced mortar there is decrease in the first crack and ultimate

strength of the material.

Rajagopalan and others (1973)4 developed equations to predict the

first crack and ultimate moment of resistance of the SFRC beams with

steel fibres. Also they concluded that there is much improvement in

ductility and large rotation capacity which can be used effectively in

redistribution of movements in beams and frames.

Swamy, R.N (1975)5 After experimental investigations on the flexural

strength of concrete by using small short steel fibres, he concluded

that the first crack strength is significantly improved. Also he has

35

derived equations to determine the first crack flexural and ultimate

flexural strength of the composite based on experimental and previous

investigations.

Charles H.Henage (1976)6 developed an analytical method based on

ultimate strength approach, which has taken into account of bond

stress, fibres stress and volume fraction of fibres. After his

investigations, he concluded that the incorporation of steel fibres

significantly increases the ultimate flexural strength, reduces crack

widths and first crack occurred at higher loads.

Shah and Naaman (1976) had conducted tensile flexural and

compressive tests on mortar specimens reinforced with different

lengths -*and volumes of steel and glass fibres. The flexural tensile

strength of the reinforced samples was 2 to 3 times that of plain

mortar while corresponding strains or deflections were as much as ten

times that of mortar. The stresses and strains at first cracking were

not notably diverse from those of plain mortar. The values of the

modulus of elasticity and the extent of nonlinearity were observed to

depend on the method of deformation measurement. Extensive micro

cracking was observed on the surfaces of failed flexural specimens

indicating a significant contribution of the matrix even after the first

cracking. For steel fibre reinforced specimens, the peak loads and

deformations appear to be linearly related to the fibre parameter

Vf*L/D. After breakdown, steel fibres pulled out while a large amount

of the glass fibres broke.

36

Naaman and Shah (1976)7 reported that for a large number of fibres,

the fibre contribution depends significantly on the capacity of the

matrix to withstand the forces enclosed by the fibres bridging the

cracked surfaces. They observed that spalling and disruption of the

mortar matrix leads to a substantial of the steel fibres in concrete

matrices necessary to increase both the bond properties of the fibre

and the matrix.

Hughes and Fattuhi (1976)8 carried out experimental investigations

on the workability of fresh fibrous concrete. They concluded that the

workability depends upon the properties and proportions of the

ingredients and also the workability decreases with increase in sand

content, volume fraction of fibres, aspect ratio, and length of the fibres

and with lesser water/cement ratio.

Krishna Raju et al. (1977)9 after conducting experimental

investigation on the compressive strength and bearing strength of

steel fibre reinforced concrete with fibre content varying from to 0% to

3%, they concluded that, both compressing and bearing strength

increases with increase in fibre content. Also the experimental results

were predicted by theoretical method.

Kormeling, Reinhardt and Shah (1980)10 after carrying out

investigations on the influence of using steel fibres on the static and

dynamic strength of RCC beams using hooked straight and raddled

fibres, they concluded that incorporation of above type of fibres

increased the ultimate moment and reduces the crack width and

average crack spacing.

37

Ramakrishnan et al. (1980)11 carried out experimental

investigations on properties of concrete like, flexural fatigue, static

flexural strength, deflection, modulus of rupture, load deflection

curves, impact strength to first crack, ultimate tensile, compressive

strength, plastic workability including vee-bee, slump and inverted

cone time by reinforcing two types of steel fibres (straight and fibre

with deformed ends) in the concrete. From the investigations, they

concluded that no balling of fibres occurred in the cone of hooked

fibres, the compressive strength is slight higher than the normal

concrete, excellent anchorage by hooked fibres resulting in ultimate

flexural strength. Also the hooked end fibres have greater ability to

absorb impact than straight fibre reinforced concrete.

Kukreja, C.B. et al. (1980)12 carried out experimental investigations

on the direct tensile strength, indirect tensile strength and flexural

tensile strength of the fibrous concrete and compared with the various

aspect ratios of the fibres as 100, 80 and 60 respectively. They

observed that maximum increase in direct tensile strength obtained

by fibres of aspect ratio 80 with 1% as volume fraction. Finally they

concluded that indirect tensile cracking stress is an inverse function

of fibre spacing and fibre reinforcement is more effective in improving

the post cracking behaviors, than the first cracking.

Narayanan and Palanjian (1982)13 carried out experimental

investigation on the properties of fresh concrete like workability in

terms of vee-bee time by incorporative crimped steel fibres of circular

cross-section. They concluded that vee-bee time increases when the

38

aspect ratio (l/b) of fibres is increased. Balling would occur with

smaller fibre content of larger aspect ratio. Also they concluded that

optimum fibres content increases linearly with increase in fine

aggregate content.

Narayanan and Kareem-palanjian (1984)15 have studied the effect of

addition of crimped and un-crimped steel fibres on the compressive

strength, splitting tensile strength and modulus of rupture of

concrete. They concluded that fibres with higher aspect ratio

exhibited greater pull – out strength and more effective than fibres

with smaller aspect ratios. Crimped fibres possess higher bond

strength than un-crimped steel fibres, finally they concluded that the

strength of concrete after adding steel fibres, is related to the aspect

ratio of fibres, fibre volume fraction and bond characteristics the

fibres. But these factors are accounted by a single parameter called

as fibre factor „F‟, Increase in the Compressive strength, splitting

tensile strength, and modulus rupture of concrete are shown by an

equation in terms of fibre factor „F‟ and strength of normal concrete.

S.P. Shah, et al. (1986)16 have found the impact resistance of steel

fibre reinforced concrete using modified charpy impact testing

machine. The size of the specimens was 76mm x 25mm x 230mm

and compressive strength was found using 76mm x 152mm cylinders.

They used brass-coated steel fibres at different volume fractions of

0.5%,1% and 1.5% were used. They observed that the impact

resistance improved with fibre additions.

39

Nagarkar, et al. (1987)17 after conducting experimental investigation

on concrete reinforced with steel and nylon fibres, they concluded that

the increase in compressive strength, splitting tensile strength and

flexural strength of concrete is more prominent in case of addition on

steel fibres than nylon fibres. They observed that compressive

strength is increased in the range of 5 to 7%, split tensile strength in

the range of 15 to 45% and flexural strength in the range of 20% to

60% respectively.

Nakagawa et al. (1989)20 carried out experimental investigation on

the compressive strength of concrete by incorporating short discrete

carbon fibres, Aramid fibres and high strength vinyl on fibres. They

concluded that compressive strength decreased as the volume fraction

of fibres is increased.

Ramakrishna et al. (1989a)21 conducted experiments to compare the

first cracking strength and static flexural strength of plain concrete

and steel fibre reinforced concrete. They used hooked end fibres upto

1% by volume. They concluded that hooked - end fibres gave

maximum increase in the above mentioned properties when compared

to straight steel fibres.

Rachel Detwiler and Kumar Mehta (1989)22 concluded that silica

fume concrete showed the greatest improvement in strength due to

combination of cement hydration and the pozzolanic reaction between

7 and 28 days.

Ghosh et al.(1989)23 after conducting experiments on cylinder split

tensile strength and modulus of rupture of concrete by using low

40

fibre content (0.4% to 0.7%) with straight steel fibres, they concluded

that split cylinder testing method is recommended for determining the

tensile strength of fibre - reinforced concrete as in the case of normal

concrete.

Kukreja and Chawla (1989)24 After conducting experimental

investigations on concrete by using straight bent and crimped steel

fibres with aspect ratio 80, they published a paper on “flexural

characteristics of steel fibre reinforced concrete”. They concluded that,

based on steel fibre content, its type and orientation, behaviour can

range from brittle to very ductile, all for the same range of flexural

strength.

Parviz Soroushian & Ziad Bayasi (1999)25 carried out experimental

investigations on the relative effectiveness of straight, crimped

rectangular, hooked - single and hooked - collated with aspect ratio of

about 60 to 75. They observed slightly higher slumps with crimped

fibres and hooked fibres are found to be more effective in enhancing

the flexural and compressive behavior of concrete than the straight

and crimped fibres.

Ezeldin and howe (1991)26 investigated the flexural strength

properties of rapid - set cement incorporated with four types of low

carbon steel fibres (two were hooked, one was crimped at ends and

one was crimped though out at ends). They concluded that the

flexural strength is controlled by the fibre surface deformation, aspect

ratio and volume fraction. They further concluded that steel fibres are

41

very effective in improving the flexural toughness of rapid-set

materials.

S.K. Saluja et al. (1992) 27 carried out experimental investigations on

the compressive strength of concrete by incorporating straight steel

fibres of aspect ratios 75, 90 and 105. They concluded that steel

fibres are effective in increasing the compressive strength to a

maximum of 13.5% at 1.50% fibre content. Also an equation was

developed to predict the experimental results.

Sameer, E.A., and Balarguru P.N. (1992)29 experimentally

investigated the stress-strain behavior of steel fibre reinforced

concrete with and without silica fume. They proposed a simple

equation to predict the complete stress-strain curve. They observed a

marginal increase in the compressive strength, the strain

corresponding to peak stress and the secant modulus of elasticity.

Also they concluded that increase of silica - fume content renders the

fibre reinforced concrete more brittle than non-silica fume concrete.

Balaguru and Shah (1992)30 said that fibre geometry (aspect ratio)

plays of vital role in the performance of straight fibres. They said that

ductility increases with the increase in aspect ratio, with the

condition, that fibres should be mixed uniformly with the concrete.

The matrix composition contributes in at least two ways to strength

and energy absorption. The first is its bonding characteristics with

the fibre and the second is the brittleness of the matrix itself, which

plays an important role in the behavior of steel fibre reinforced

concrete.

42

Balaguru and Shah (1992)31 In their state of art report say that, the

other factors to be considered in the design are, modulus of elasticity,

strain at peak load and post peak behavior. They said that the

addition of fibres increases the strain at peak load and results in a

less steep and more gradual descending branches. Finally, fibre

reinforced concrete has been found to absorb much more energy

before failure when compared to normal concrete.

Faisal F Wafa and S.A. Ashour, (1992) 32 carried out experimental

investigations on properties like, cube compressive strength, splitting

tensile strength and modulus of rupture of concrete by incorporating

hooked - end steel fibres with 0% to 1.5% as volume fraction. They

concluded that addition of 1.50% by volume of hooked end fibres

resulted in 4.6% increase in compressive strength, 59.80% increase in

split tensile strength and 67% increase in modulus of rupture of plain

cement concrete. Also they developed equations for predicting the

experimental results.

Bayasi and Zeng (1993)34 proposed that flexural behavior of

polypropylene fibres be characterized by the post-peak flexural

resistance. They found that long fibres were more favorable for

enhancing the post-peak resistance. The effect of silica fume on the

compressive properties of synthetic fibre-reinforced concrete by using

fibrillated polypropylene and polyethylene erphalate polyester fibres

was studied by bayasi celik. He concluded that both types of fibres

improved the compressive behavior by enhancing the toughness and

also, both the fibres increased the strain at peak compressive stress.

43

Agrawal, A.K. Singh and Singhal D. (1996)39 studied the effect of

fibre reinforcing index on the compressive strength and bond behavior

of steel fibre reinforced concrete by using straight circular Galvanized

Iron fibres with aspect ratios of 60, 80 and 100. The maximum fibre

content was taken as 1.50% by volume of concrete. The results show

an increase in compressive and bond strength of steel fibre reinforced

concrete when compared to normal concrete. They also developed

relationships to relate compressive and bond strength with fibre

reinforcing index (FRI).

Gupta A.P., et al. (1998)41 carried out experimental study on

compressive strength of concrete by using crimped steel fibres of

circular in cross-section with three volume fractions of 0.5%, 1.0%and

1.5% and with two aspect ratios 55 and 82. They proposed an

equation to quantify the effect of fibre addition on compressive

strength of concrete in terms of reinforcing index (RI) based on

regression analysis.

Singh, A.P. & Dr. Singhal, D., (1998)42 After studying the

permeability of steel fibre reinforced concrete by using plain steel

fibres at various percentages (0% & 4%) they observed that

permeability is decreasing significantly with the addition of fibres and

it continued to decrease with the increase in fibre content. Also linear

relation ship was observed between permeability and compressive and

tensile strength for plain cement concrete.

R.M. Vasan et al (1999)47 investigated the effect of hook shaped steel

fibres of circular in cross-section on the compressive strength, flexural

44

strength, impact strength and modulus of elasticity of high strength

concrete. From the results, they observed that the above properties of

concrete were improved due to the addition of 0.5% volume of steel

fibres.

Nataraja, Dhang, Gupta (2001)62 studied the effect of addition of

crimped round steel fibres on the splitting tensile strength of concrete.

They proposed equations based on linear regression analysis to

correlate splitting tensile strength with the fibre reinforcing index.

Linear relation ship between splitting tensile strength and the flexural

strength, split tensile strength and compressive strength were also

proposed.

O.Kayali et al. (2003)69 carried out experimental investigation on the

effect of polypropylene and steel fibres on high strength light weight

aggregate concrete. Sintered fly ash aggregates were used in the light

weight concrete. By adding polypropylene fibres at 0.56% by volume

of the concrete caused a 90% increase in the indirect tensile strength

and a 20% increase in the modulus of rupture, where as addition of

steel fibres at 1.70% of volume of concrete increased the indirect

tensile strength by about 118% and 80% increase in modulus of

rupture. Finally there is a significant gain in ductility when steel

fibres are used.

Kaushik S.K., et al. (2003)70 carried out experimental investigation

on the mechanical properties of reinforced concrete by adding 1.0%

volume fraction of 25mm and 50 mm long crimped type flat steel

fibres. It was observed that short fibres acts as crack arrestors and

45

enhances the strength, where as long fibres contributed to overall

ductility. They concluded that best performance was observed with

mixed aspect ratio of fibres.

Peter H.Bischoff (2003)72 studied the post cracking behavior of

reinforced tension members made with both plain and steel fibre -

reinforced concrete. He concluded that specimens with steel fibres

exhibited increased tension stiffening and smaller crack spacing,

which both contributed to a reduction in crack widths. Also it is

observed that cyclic loading did not have a significant effect on either

tension stiffening (or) crack width control for the specimens tested.

Kolhapure B.K. (2006)91 investigated experimentally the mechanical

properties of concrete using recron 3S fibres along with super

plasticizer. He concluded that compressive strength, tensile strength

and flexural strength is increased by 30%, 23% and 24% when

compared to plain concrete.

2.4 REVIEW OF LITERATURE OF SFRC ON IMPACT

RESISTANCE

Romualdi and Batson (1963)1 after conducting impact test on fibre

reinforced concrete specimens, they concluded that first crack

strength improved by addition of closely spaced continuous steel

fibres in it. The steel fibres prevent the adverting of micro cracks by

applying pinching forces at the crack tips and thus delaying the

propagation of the cracks. Further, they established that the increase

46

in strength of concrete is inversely proportional to the square root of

the wire spacing.

Sridhara, S., et al. (1971)2 carried out experimental investigations to

study the blast resistance of concrete, by adding different types of

fibres like, nylon, coir and Jute at various percentages by volume of

concrete. They concluded that fibres increased the impact and shatter

resistance of concrete. Out of nylon fibres even at low fibre contents

found to be the most effective reinforcement for increasing the impact

strength of the concrete.

Swamy, R.N. (1974)3 studied the mechanical properties and

applications of fibre reinforced concrete using polypropylene, glass,

asbestos and steel fibres. The factors influencing the effectiveness of

fibre reinforcement and the efficiency of stress transfer were

discussed. The author concluded that Asbestos, glass and steel fibres

can be used at higher temperature than the low modulus fibres like

nylon and polypropylene which lose their load carrying capacity

around 1000C. The great improvements in impact resistance and

ductility at failure provided by glass, steel and plastic fibres are not

reflected by asbestos, whose characteristic property is its high tensile

strength.

Charles H. Henage (1976)6 developed an analytical method based on

ultimate strength approach, which has taken into account of bond

stress, fibres stress and volume fraction of fibres. After his

investigations, he concluded that the incorporation of steel fibres

47

significantly increases the ultimate flexural strength, reduces crack

widths and first crack occurred at higher loads.

E.K. Schrader (1981)13 has developed a simple, portable and

economical test device which measures the impact resistance. This

impact test device is called the schrader‟s test device and the test

method is called drop weight test method. The number of impact

blows delivered by a drop hammer is accumulated until the first

visible crack occurs and until the test specimens is forced to separate

by continued impacting. The test is best suited for fibrous concrete.

Initial data shows that it can also serve as an indication of other

material properties such as toughness, strain capacity and fatigue

performance.

Shah S.P., et al. (1986)16 have found the impact resistance of steel

fibre reinforced concrete using modified charpy impact testing

machine. The size of the specimens was 76mm x 25mm x 230mm

and compressive strength was found using 76mm x 152mm cylinders.

They used brass-coated steel fibres at different volume fractions of

0.5%, 1% and 1.5% were used. They observed that the impact

resistance improved with fibre additions.

Alhozaimy, A.M., et al. (1995)37 After experimental investigations

they concluded that increased effectiveness of fibres in the presence of

pozzolans could be caused by the improved fibre to matrix bonding

associated with the action of pozzolans in the concrete.

Balasubramanian et al. (1996)41 studied the impact resistance of

steel fibre reinforced concrete using drop weight test method. They

48

varied the fibre volume fractions as 0.5% to 2% for each of the three

types of steel fibres (Straight, Crimped and Trough shaped fibres).

These fibres were of aspect ratio 80. They concluded that impact

resistance increased with increase in fibre volume fraction. Also they

concluded that among the three types of fibres, crimped fibres showed

higher impact resistance than straight and trough shape fibres.

Bindiganavalie. V and Banthia. N (2002)64

The authors on the topic “Some studies on the Impact Response

of Fibre Reinforced Concrete” made an attempt to examine two major

issues related to impact loading on plain and fibre reinforced concrete.

Firstly, within the context of drop weight impact tests, a number of

machine parameters were examined including capacity size (150J –

15,000J) and drop heights (1.2m – 2.5m). It was found that the

machine parameters strongly control the experiential material

response to impact. Secondly, a comprehensive test program

launched where steel and polymer fibres with widely different

constitutive properties were compared as reinforcement in concrete

under impact loading.

Based on the experimental investigation they observed that

For cement – based materials, the measured impact response is

highly dependent on the characteristics of the drop-weight impact

machine used for testing. The pulse duration was found to depend

upon the drop-height, with greater drop-height leading to shorter

pulses. Results appear to be far less sensitive to the mass of the

49

hammer than to the drop-height. This observation forms a useful

basis for standardizing impact testing of plain and fibre reinforced

concrete. Results from two different machines with varying hammer

masses can be compared if the drop height were identical.

Crimped polypropylene fibre is less effective than steel fibre at

quasi-static rates of loading. However, a higher stress rates, in

performed better than the steel fibre. This „switch‟ in the behavior of

FRC is attributed to the greater strain rate sensitivity of polypropylene

visa vis steel.

Song, Hwang and Shou (2004)82 carried out experimental

investigations to study the impact resistance of steel fibre reinforced

concrete using drop weight test method. They used hooked end fibres

with 0.55mm in diameter and 35mm long. They concluded that steel

fibrous concrete improved to various degrees to first crack and failure

strengths and residual impact with standing capacity over the non-

fibrous concrete.

2.5 REVIEW OF LITERATURE OF OPCC, PPC & SFRC

WHEN EXPOSED TO ELEVATED TEMPERATURES

Mohammed Bhai G.T.G (1983)14 The experimental work done by

Prof.G.T.G. MOHAMMED BHAI, describes tests carried out to

determine the effect of high temperatures on the residual compressive

strength of concrete used in Mauritius. The rock formation in

Mauritius, an island of the volcanic origin is mostly basaltic. The

course aggregate used for making concrete in Mauritius is invariably

50

crushed basalt. The fine aggregate can be either coral sand or

crushed basalt. The effect of method of cooling and that of age after

heating were included in the investigation. In order to determine

whether any physical or chemical changes take place in the coral sand

and basalt on heating-ray diffraction tests were carried out, one on un

heated sample and other three on samples which has been heated for

two hours to 2000C, 5000C and 8000C respectively and then cooled

down to room temperature.

The following conclusions were drawn by the author:

1) When subjected to high temperatures the residual strength of

concrete made with coral sand is significantly less than that of

concrete made with basalt sand. This appears to be due to some

chemical/physical changes, which occur, in coral sand when heated

beyond 3000C.

2) The method of cooling has no significance influence on the

residual strength of concrete heated up to 4000C, but for higher

temperatures air cooled specimens have a lower residual strength

than water cools ones.

3) Air-cooled specimens show a further loss in strength from one

day to seven days after heating. Water cooled specimens, however

exhibited a recovery in strength over the same period.

R.Sarshar and G.A. Khoury (1993)35 The authors carried out

experimental investigations on the uniaxial compressive strength

conducted on cement paste and concrete specimens heated to

temperatures up to 6000C. They investigated on the concrete cement

51

paste and aggregate and a cement blend containing 65% slag

replacement of ordinary Portland cement by weight. They concluded

that at 6000C, the hot compressive strength of this material was 85%

of the value measured before heating. Also they concluded that, both

material and environmental factors have a significant influence during

the heat cycle and after cooling. In several cases the fast cooling

resulted in higher residual strength. Specimens containing slag

retained a higher proportion of their strength, than specimens

containing 100% OPC after quenching from 5200C.

Abha Mittal et al. (1994)36 The authors on the topic “Residual

Strength in concrete after exposure to elevated temperature” reveal

that the loss of concrete strength when exposed to higher

temperatures and the recovery of lost strength due to dehydration of

concrete with time was a support of evidence for the earlier

experimental works done on the effect of high temperatures on

compressive strength of concrete.

Based on the Experimental investigations they concluded:

An increase in compressive strength for exposure to lower

temperature below 1000C this may be partly attributed to accelerated

hydration of unhydrated cement. The compressive strength is

drastically affected in higher ranges of temperature and the time of

exposure.

With time, there is a recovery of compressive strength due to

rehydration of concrete. The recovery may be about 80 percent of the

initial strength. This was also been observed by other research

52

workers, that concrete which has been heated at temperature below

5000C rehydrates while cooling down and gradually regains most of its

lost strength.

B.Zhang, N.Bicanic, C.J.Pearce and G.Balabanic (2000)53 An

investigation is done by the above authors to study the effect of

elevated temperature (tm) related to the explosive period (th) and the

curing age (ta) on the residual fracture properties of normal strength

concrete (NSC) and high strength concrete (HSC), by conducting three

point bending tests on preheated beams. Most beams were exposed to

temperature between 1000C and 6000C for 12 hrs at 14 days. The

weight loss (W) was also monitored. The following conclusions are

made by the authors.

i). Weight loss is a parameter that can help to distinguish three

different regimes. When the heating temperature is under 2000C, the

weight loss is completely caused by the quick evaporation of capillary

water, and the concrete undergoes a physical process. For a

temperature between 2000C and 4000C, the weight loss is mainly

caused by the gradual evaporation of gel water, and the concrete

undergoes a mixed physio-chemical process. For a temperature over

4000C, the weight loss is mainly caused by the evaporation of

chemically bound water (dehydration) and decomposition, so the

concrete undergoes longer weight loss, but a greater curing age slows

down the evaporation rate because of further hydration.

ii). The concrete strength parameters do not change very much

when the temperature is under 2000C, there after they decrease

53

rapidly with increasing heating temperature. A longer explosive period

increases the strengths slightly at lower temperatures but reduces

them at higher temperatures. A greater curing age always helps to

increase strength.

iii). The concrete brittleness has been assessed using the

characteristic length. Increasing temperature decreased the

brittleness, but this reduction is obtained with a significant loss of

strength for higher temperature. The brittleness decreases much

more rapidly for high-strength concrete. A longer exposure period

decrease the brittleness but a greater curing age increases the

brittleness slightly. The brittleness of the concrete always decreases

with increasing weight loss, and the rate of decrease becomes much

greater for higher weight loss.

Maria de Lurdes et al. (2001)60 Authors carried out experimental

investigations on the compressive strength of steel fibre reinforced

high strength concrete (SFHSC) subjected to high temperatures. The

concrete samples were preheated to various temperatures, and the

subsistence of a cooling stage was measured as a variable. They

concluded that during the heating phase the compressive strength of

the SFHSC was shown to be more affected by high temperatures than

normal - strength concrete without fibres. In general, a gain in

compressive strength in the specimens was observed after cooling,

except at 3000C, there was always a gain in compressive strength after

the specimens cooled for all maximum preheating temperature levels.

This recovery varied according to the maximum heating temperature

54

level, but reached as much as 20% for maximum heating

temperatures of 500 – 6000C. At 2000C, the residual strength was

higher than the concrete strength before heating.

Sun. W.Luo X, Chan. S.Y.N (2001) Studied the “Properties of high

performance concrete exposed to high temperature”. Pore structure

measured by means of mercury intrusion porosimetry (MIP) was

studied to determine the changes in the interior structure of the

concrete before and after high temperatures. They concluded that

thermal shock for matured concrete was not a principal factor causing

spalling of high performance concrete. Inclusion of steel fibres

improved the residual properties, if they did not melt at high

temperatures.

Phan, L.T. Law son, J.R. and Davis, F.L. (2001) studied the “Effects

of elevated temperatures on heating characteristics, spalling and

residual properties of HPC”. They conducted experimental study on

HPC with and without silica fume. They observed that the differences

in modulus of elasticity are less significant and the potential for

explosive spalling increased in high performance concrete specimens

with lower water to cement ratio and silica fume.

Long T. Phan and Nicholas Carino J. (2002)63 In their experimental

investigations, mechanical properties of high strength concrete

exposed to elevated temperatures were measured by heating 100 x

200 mm cylinders at 50C/min to temperature up to 6000C. After

Heating was done with and without a continued stress, properties

were considered at elevated temperatures as well as after cooling to

55

room temperature. Four mixtures with different water-cementitious

materials ratios (w/cms) were used, out of which two mixtures

enclosed silica fume. Measured compressive strengths and elastic

modulii were normalized with respect to room temperature values, an

analysis of variance was used to determine whether the test condition,

the values of w/cm, or the presence of silica fume affected the results.

The influence of these variables on the tendency for explosive spalling

was also examined by the authors on the topic “Effect of Test

Conditions and Mixture Proportions on Behavior of High-Strength

Concrete Exposed to High Temperatures”. Results indicated that

losses in relative strength due to high temperature exposure were

affected by the test condition and w/cm, but there were significant

interactions among the main factors that resulted in complex

behaviours. The occurrence of silica fume does not come out to have

a major effect. Measurements of temperature histories in the

cylinders revealed complex behaviours that are believed to be linked to

heat-induced transformations and transport of free and chemically

combined water.

Bowu, Xiao – Ping Su, Huili (2002) Studied the effect of high

temperature on residual mechanical properties of confined and

unconfined high strength concrete. They varied the temperature from

1000C to 9000C. Also elastic modulus decreases sharply at the higher

temperatures.

R.V.Balendran, T.M. Rana, T.Magsood, W.C.Tang (2002)

Investigated on “Strength and durability performance of high

56

performance concrete containing pulverized fuel ash, silica fume and

Metakaolin as pozzolans at elevated temperatures”. The addition of

silica fume showed poor performance with respect to strength and

spalling at higher temperatures. Finally, they concluded that addition

of pulverized fuel ash and Metakaolin improved the fire performance of

high performance concrete in terms of residual strength and

durability.

Chi-Sun Poon, Salman Azhar, Mike Anson and Yuk-hung Wong

(2002) Investigated on “Comparison of the strength and durability

presentation of normal and high strength pozzolanic concretes at

elevated temperatures”. Silica fume, fly ash and blast furnace slag

were used as pozzolans. They concluded that pozzolanic concrete

showed best performance when compared to plain concretes. After

4000C, both HSC and normal strength concrete lost their strength

rapidly and also severe deterioration and spalling was observed in

both concrete for temperatures above 4000C.

Chi-sun poon, Salman Azhar, Mike Anson, Yuk-Luny Wong

(2003)71 The authors carried out experimental investigations to

evaluate the performance of Metakaolin (MK) concrete at elevated

temperatures upto 8000c. Eight normal and high strength concrete

(HSC) mixes incorporating 0%, 5%, 10% and 20% MK were prepared.

It was found that after an increase in compressive strength at 2000C,

the MK concrete suffered a more severe loss of compressive strength

and permeability – related durability than the equivalent silica fume,

fly ash and ordinary Portland cement concretes at higher

57

temperatures. Likely to explode spalling was observed in both normal

and high - strength Metakaolin concretes and the frequency increased

with higher Metakaolin contents.

The Metakaolin concrete show a different outline of strength

gain and loss at elevated temperatures. After gaining an increase in

compressive strength at 2000C, it maintained higher strength as

compared to the corresponding SF, FA and pure OPC concretes up to

4000C. A sharp reduction in compressive strength was observed for

all HSC after 4000C followed by severe cracking and explosive spalling

within the range 400 – 8000C. MK concretes suffered more loss and

possessed lower residual strength than the other concretes. Dense

micro – structure and lower porosity are the main reasons for the poor

performance of MK concrete at elevated temperatures. Explosive

spalling was observed in both normal and high strength MK concrete

specimens particularly between 450 and 5000C. The spalling

occurrence increased with the higher Metakaolin content. The vapour

pressure build-up by dense pore – structure seems to be the obvious

reason for such spalling. The MK concrete with 5% cement

replacement showed better performance than the corresponding pure

OPC and SF concretes at all tested temperatures. No spalling was

experiential in this concrete.

V.K.R. Kodur and Tien – Chih Wang et al. (2004)83 The authors

carried out experimental investigations on the strength and stress -

strain relationship of high strength concrete (HSC) at elevated

temperatures. They investigated at 1000C, 2000C, 4000C, 6000C and

58

8000C for plain high strength concrete and fibre reinforced high

strength concrete. The variables considered in the investigations

included concrete strength, type of aggregate and the addition of steel

fibres. They concluded that the compressive strength of HSC

decreases by about a quarter of its room temperature strength with in

the range of 100-4000C. The strength further decreases with the

increase in temperature and reaches about a quarter of its initial

strength at 8000C. The increase in strains for carbonate aggregate

high strength concrete is bigger than that for siliceous aggregate high

strength concrete. They observed that plain high strength concrete

exhibits brittle properties below 6000C and ductility above 6000C.

Also they concluded that incorporation of fibres exhibits ductility over

higher temperatures and the strain at peak loading increases from

0.003 at room temperature to 0.02 at 8000C.

Srinivasa Rao K., Potha Raju. M. and Raju P.S.N. (2004)84 The

extensive use of concrete as a structural material for the high rise

buildings, storage tanks, nuclear reactors , and pressure vessels

increase the risk of concrete being exposed to high temperatures.

This has led to a demand to improve the understanding of the effect of

the temperature on concrete. The behaviour of concrete exposed to

high temperatures is a result of many factors including the exposed

environments and constituent materials. High strength concrete (HSC)

is characterized by the use of extremely low w/b ratio and a highly

compact mix using suitable methodologies. The authors in their

experimental investigation on the effect of temperature and to evaluate

59

the structural safety an attempt was made to study the residual

strength of high strength concrete exposed to high temperatures at

different ages. From this study it was found that older concrete

suffered less loss than younger concrete within the temperatures

range of 100o C to 250o C. In older concrete of 28 and 56 days of age

the behavior is similar. This may be due to completion of hydration of

cement and micro cracking around hydroxide crystals. Based on the

Experimental investigations they concluded

Rapid decrease in strength was observed at 50o C for all

exposure durations of 1, 2 and 3 hrs at 7 days age of concrete. This

may be due to incomplete hydration of cement.

An increase in strength was observed in the temperature range

of 50oC to 100oC for all exposure durations of 1, 2 and 3 hrs at 7 days

age of concrete. This may be attributed to the accelerated hydration of

cement.

A gradual reduction in strength was found with increase in

temperature from 100oC to 250oC for all exposure durations of 1, 2

and 3 hrs at 7 days age of concrete.

Behavior of 28 and 56 days concrete was similar showing

reduction in strength with increase in temperature for all exposure

durations.

Older concrete exhibited less loss of strength compared to

younger concrete at all temperatures.

Y.F. Fu, W.L. Wong et al. (2005)89 The authors carried out

experimental investigations on the effects of mineral additions and

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test conditions on the stress-strain relation of high strength concrete

when exposed to elevated temperatures. They observed that, addition

of fly ash (FA) was effective in improving the residual properties

(compressive strength and elastic modulus) of concrete. All the

concrete mixes had higher residual mechanical properties in the

stressed test than in the unstressed test. In the stressed test

condition, all the concrete mixes retain elastic modulus values close to

the inventive unheated values.

Jainzhuang Xiao and H. Falkner (2005) Carried out experimental

investigation on the residual strength of high performance concrete

using polypropylene fibres at elevated temperatures. They compared

the residual strength of HPC with and without polypropylene fibres.

Finally they observed no spalling in HPC containing fibres when

compared to any HPC specimens. Also a relationship between the

mass loss and the exposure temperature was developed.

K.D.Hertz and L.S.Soren Sen (2005) developed a new material test

method for determining whether (or) not an actual concrete may suffer

from explosive spalling at specified moisture level. They concluded

that sufficient quantities of polypropylene fibres may prevent spalling

of a concrete even when thermal expansion is restrained.

Srinivasa Rao .K., Potha Raju .M. and Raju P.S.N. ( 2006 )90: High

strength (HSC) is being used in high rise buildings ad a variety of

industrial structures which may be subjected to elevated

temperatures during operation or in case of an accidental fire. Bed

ford reported that staggering loss of £ 850 million per annum occurs

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on account of fire damage to buildings. This necessitates proper

understanding of the effects of elevated temperatures on the

properties of HSC. The authors made an attempt to study the effects

of elevated temperatures ranging from 500c and 2500c on the

compressive strength of HSC made with both ordinary Portland

cement (OPC) and Portland pozzolana cement (PPC). The residual

compressive strengths were evaluated at different ages. The results

showed that at later ages HSC made with Portland pozzolana cement

performed better by retaining more residual compressive strength

compared to concrete made with ordinary Portland cement. Based on

the experimental investigation they concluded

Both OPC and PPC concrete gained compressive strength on

heating till a temperature of 1500c at early ages of 1 and 3 days. This

could be due to acceleration in hydration process on heating. The

increase in percentage residual compressive strength in the range of

10 to 30 percent for OPC and PPC concretes when exposed to elevated

temperatures for 3 hours. Both concretes experienced reduction in

residual compressive strength at the age of 1 and 3 days beyond 1500c

temperature.

The residual compressive strength of OPC and PPC concretes at

the age of 7, 28, 56 and 91 days decreased steadily with increase in

temperature.

OPC concrete retained more percentage of residual compressive

strength compared to PPC concrete at early ages up to 7 days.

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However, PPC concrete performed better by retaining more residual

compressive strength compared to OPC concrete at later ages.

PPC concrete appeared to have lower decrease in percentage

residual compressive strength than OPC concrete for similar

conditions. OPC concrete exhibited maximum decrease of 40 percent

residual compressive strength at 2500C whereas, PPC concrete

exhibited maximum decrease of 18 percent in residual compressive

strength.

2.6 REVIEW OF LITERATURE OF OPCC & PPC ON

THERMAL CYCLES

Bairagi N.K. and Mr. Dubal N.S. (1996)41 The experimental work

done by authors on “Effect of thermal cycles on compressive

strength, modulus of rupture and dynamic elastic modulus of

concrete” reveal the behaviour of concrete when bare to thermal

cycles. The investigation was planned to be carried out through an

experimental program on concrete specimens for which M20 grade

concrete mix was designed as per the guidelines laid down by IS

10262 – 1982. Ordinary Portland cement confirming to IS269 – 1967

was used. Locally available coarse and fine aggregates were used to

prepare the mix. . Aggregate cement ratio of 6.0 and water cement

ratio of 0.53 was used in the test program. The specimen used was

plain concrete beams of the size 100 x 100 x 500 mm. In their study

two cases of thermal cycles were chosen. In one case concrete was

heated to a maximum temperature of 600C and in another it was

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heated to a maximum temperature of 900C. The specimens were

heated in an oven from room temperature in about two hours,

maintaining the maximum temperature for about 6 hours and then

letting it cool down to room temperature in another 16 hours, all these

constitute the completion of one thermal cycle. The specimens were

subjected to 0, 30, 60, 120, 240 and 365 thermal cycles.

After subjecting to the requisite number of thermal cycles the

specimens were treated fro dynamic modulus of elasticity as measured

by the resonant frequency method. To find the dynamic modulus of

elasticity the beam was first held as a cantilever beam, with one end

fixed (held under a screw jack) and other end free. Miniature piezo

electric transducer was fixed at the free end of the specimen. An

impact was applied using an impact hammer. The beam vibrated

under this impact load. The vibrations were picked using the

miniature piezo electric transducer. The signal obtained from the

transducer was amplified using amplifiers and then the signals were

analyzed using a FFT (Fast Fourier Transform) analyzer to obtain the

natural frequency of vibration of the specimen. This value of natural

frequency was further utilized to determine the dynamic modulus of

elasticity. After completion of the dynamic modulus of elasticity test,

the specimens were tested to determine the modulus of rupture using

the two point loading as per I.S.516-1959. The compressive strength

was measured from tests carried out on broken pieces of the beam

obtained after the flexural test. Each value of the compressive

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strength and dynamic modulus of elasticity was taken as an average

of three values obtained from three identical specimens.

From the experimental investigation carried out the following

conclusions were given by them.

The dynamic modulus of elasticity decreased with increased in

the number of thermal cycles. At both 600C and 900C thermal cycles,

the rate of reduction is found to be maximum after 30 thermal cycles

and it is reduced with increase in the number of thermal cycles. At

600C the rate of reduction is found to be 17.1% for thermal cycles and

26% for 365 thermal cycles. In case of concrete subjected to 900C the

rate of reduction after 30 thermal cycles is 27% and 41% for 365

thermal cycles. The maximum reduction occurred after 365 thermal

cycles for both 600C and 900C. However the rate of reduction is

higher for specimens subject to 900C thermal cycles, as compared to

that of specimens heated at 600C thermal cycles.

Similarly, thermal cycles have an adverse effect on the

compressive strength as well. Once again the rate of reaction is found

to be maximum after 30 thermal cycles for specimens subjected to

both 600C and 900C, which is 16% and 21% respectively, and there

after decreased gradually with increase in the number of thermal

cycles. However the maximum reduction in compressive strength

occurred after 365 thermal cycles for specimens subjected to thermal

cycles at 600C and 900C which is 26% and 35% respectively, showing

that the specimens heated at 900C are more adversely affected when

compared to those heated at 600C.

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Thermal cycles affect the flexural strength as well. For flexural

strength also the rate of reduction in strength is highest at 30 thermal

cycles and it decreases gradually for further increase in thermal

cycles. The percentage reduction is 3.9% for 600C and 17% for 900C.

The rate of reduction once again being higher for specimens subjected

to 900C.

The adverse effect of thermal cycles on the studied properties of

concrete is probably due to thermal incompatibility of concrete

constituents. Investigations have shown that micro cracks exist at the

interface between coarse aggregate and cement paste even prior to the

application of load on concrete. In the case of concrete subjected to

thermal expansion of cement matrix and aggregates. Internal stress

created due to unequal expansion or contraction of the concrete

constituents might lead to an increase in the micro cracks.

Srinivasa Rao P., Sravana P. and M.V. Seshagiri Rao, (2006)89 :

Concrete structures were exposed to temperature variations mainly

due to solar radiation. As mentioned literature, concrete containing

pure OPC exhibit a steady turn down in residual compressive concrete

strength when subjected to thermal cycles. The authors made

investigation on M20 and M30 grades of concrete containing OPC and

fly ash by exposing them for various thermal cycles at different

temperatures. Mechanical properties like compressive strength,

splitting tensile strength and dynamic modulus of elasticity were

evaluated and compared. The results discovered that concrete

containing fly ash was more successful in resisting the effect of

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thermal cycles than concrete containing ordinary Portland cement.

Based on the Experimental investigations they concluded

The thermal cycles have adverse effect on the compressive

strength of ordinary concrete.

The compressive strength of ordinary concrete for M20 and M30

decreased by about 13 percent at 500 C after 28 thermal cycles.

However for fly ash concrete the compressive strength was found to

increase by 11 percent, after 28 thermal cycles at 500 C.

The compressive strength of ordinary concrete for M20 and M30

decreased by about 25 percent at 1000 C after 28 thermal cycles.

However for fly ash concrete the compressive strength was found to

increase by 11 percent, after 28 thermal cycles at 1000 C.

The split tensile strength or ordinary concrete for M20

decreased by about 14 percent and for M30 decreased by 11 percent

at 500 C after 28 thermal cycles. However for fly ash concrete the split

tensile strength was found to increase by 12 percent and 7 percent for

M20 to M30 after 28 thermal cycles at 500 C respectively.

From the literature that the specimens were heated in oven from

room temperature to maximum temperature in about 2 hours and

maintaining the maximum temperature for another six hours and

letting it cool down to room temperature in another 16 hours, all these

constitute one thermal cycle. The thermal effects have an adverse

effect on the compressive strength and dynamic modulus of elasticity

of ordinary concrete. However for fly ash concrete the compressive

strength was found to increase by 11 percent, after 28 thermal cycles

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at 1000 C. The split tensile strength was found to increase by 12

percent and 7 percent for M20 to M30 after 28 thermal cycles at 500 C

respectively.

CONCLUSIONS BASED ON THE REVIEW OF LITERATURE

The conclusions arrived from the study of the above review of

literature are as follows:

(a) The use of Metakaolin in concrete as replacement of cement

resulted in:

Pozzolanic materials like Metakaolin when used as cement

replacement materials in concrete improves the properties of concrete

due to the more consumption of Ca(OH)2, better pore refinement,

micro filling action, more resistant to permeability, Early gain of

strength, higher pozzolanic reaction and also helps in reducing the

consumption of cement. This leads to saving of natural resources and

reduction in the emission of green house gases like CO2.

The above existing literature indicates that many researchers have

studied the few strength properties of ordinary Portland cement

concrete using Metakaolin as cement replacement material. Not much

literature is available on durability properties and also no literature is

available on behaviour of Metakaolin concrete exposed to different

thermal cycles at various temperatures. Also no comprehensive study

was done on strength and durability properties of Metakaolin concrete

using crimped steel fibres. Hence, considering the gap in the existing

literature, an attempt has been made to study the strength, durability

properties, flexural behaviour of beams and slabs by addition of

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crimped steel fibres of various aspect ratios at different volume

fractions.