experimental study on effect of silica fume with natural cellulose fibre in frc

8/13/2019 Experimental Study on Effect of Silica Fume With Natural Cellulose Fibre in FRC

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Experimental Study on Effect of Silica Fume With Natural Cellulose Fibre in FRC

2012-201

CHAPTER 1

INTRODUCTION

1.1 GENERAL

Concrete is a !ersatile material" #hich is #idely used for construction material in the

#orld$ %t is obtained by mixin& cementitious materials" #ater" a&&re&ate and

sometimes admixtures in re'uired proportions$ Fresh concrete or plastic concrete is

freshly mixed material #hich can be moulded into any shape hardens into a roc(-li(e

mass (no#n as concrete$ )he hardenin& is because of chemical reaction bet#een

#ater and cement" #hich continues for lon& period leadin& to stron&er #ith a&e$

Concrete is the preferred construction material in %ndia$ )he cement production has

increased" than(s" mainly* to the rene#ed thrust on infrastructure de!elopment in the

country$ %n the past fi!e-six years me&a construction pro+ects in!ol!in& the use of

concrete ha!e been executed in the country in alar&e number$ Some of them include

construction of a lar&e number of flyo!ers" ,elhi metro rail" atomic and thermal

po#er plants" &olden 'uadran&le road pro+ect" and reconstruction of u+arat after

.anuary 2001 earth'ua(e" etc$ )he 'uality and type of concretes bein& employed ha!eunder&one a transformation #ith the use of state of the art concrete technolo&y$

/mon&st the recent de!elopments in the field of concrete such as i&h erformance

Concrete C3" Compacted Reinforced Concrete CRC3 Reacti!e o#der Concrete

RC3" Self-compactin& Concrete" etc$" C could find applications in %ndia in some

of the presti&ious pro+ects$ 4156

1.2 CONCRETE AND ITS QUALITY

Concrete 7 Cement 8 Sand 8 /&&re&ate 8 Water 8 /dmixtures 8 /ir$

)he mixture of cement and #ater is called paste$ )he function of paste is to bind

sand and a&&re&ate particles by the chemical process of hydration$ %t also fills the

!oid ratio bet#een sand and a&&re&ate particles$ )he stren&th of concrete depends

upon the properties of cement" sand" a&&re&ates" etc$

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)he >olanic materials #hich can be used in

concrete as partial replacement of cement$ / number of studies are &oin& on in

%ndia as #ell as abroad to study the impact of use of these po>>olanic materials as

cement replacements and the results are encoura&in&$ )he stren&th" durability and

other characteristic of concrete depends on the properties of its in&redients"

proportion of mix" method of compaction and other controls durin& placin& and

curin&$

Chemical and mineral admixtures and methods to produce concrete of needed

characteristics are discussed$ )he concrete mix proportion has an important

influence on producin& &ood 'uality concrete$ )ypical data of stren&ths of

concrete for different #ater-cementitious materials ratios #ith different

percenta&es of fly ash or &round &ranulated blast furnace sla& sho# that such

concretes are comparable made usin& 5-&rade ordinary ortland cement #ithout

any fly ash ?&round &ranulated blast furnace sla&$ o#e!er" #hen silica fume is

used #ith super plasticiser" the stren&th of concrete can be increased to @0 toA0;a$4126

Buality of concrete depends on the constituent materials" their proportions"

mixin&" transportin&" placin&" compaction and curin& of concrete$ )he concrete

#ith proper mix proportion has the needed #or(ability and de!elops the tar&eted

compressi!e stren&th$ Efficient concrete mixers are needed to mix the in&redients

and to produce a cohesi!e and #or(able concrete$ Concrete admixtures play an

important role in pro!idin& the needed #or(ability for transportin& and placin&



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the concrete in the form#or($


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%:$ Self-Compactin& Concrete

1.3.1 High Perfor!"#e Co"#re$e

i&h-performance concrete C3 exceeds the properties and constructability of

normal concrete$ Normal and special materials are used to ma(e these specially

desi&ned concretes that must meet a combination of performance re'uirements$

Special mixin&" placin&" and curin& practices may be needed to produce and handle

hi&h-performance concrete$ Extensi!e performance tests are usually re'uired to

demonstrate compliance #ith specific pro+ect needs$ i&h-performance concrete has

been primarily used in tunnels" brid&es" and tall buildin&s for its stren&th" durability"

and hi&h modulus of elasticity$ %t has also been used in shotcrete repair" poles" par(in&

&ara&es" and a&ricultural applications$

i&h performance concrete characteristics are de!eloped for particular applications

and en!ironments" some of the properties that may be re'uired include*

i&h stren&th

i&h early stren&th

i&h modulus of elasticity

i&h abrasion resistance

i&h durability and lon& life in se!ere en!ironments

Do# permeability and diffusion

Resistance to chemical attac(

i&h resistance to frost and deicer scalin& dama&e

)ou&hness and impact resistance

:olume stability

Ease of placement

Compaction #ithout se&re&ation

%nhibition of bacterial and mould &ro#th



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i&h-performance concretes are made #ith carefully selected hi&h-'uality in&redients

and optimi>ed mixture desi&ns these are batched" mixed" placed" compacted and

cured to the hi&hest industry standards$ )ypically" such concretes #ill ha!e a lo#

#ater cementin& materials ratio of 0$20 to 0$5$ lastici>ers are usually used to ma(e

these concretes fluid and #or(able$

i&h-performance concrete almost al#ays has a hi&her stren&th than normal concrete$

o#e!er" stren&th is not al#ays the primary re'uired property$ For example" a normal

stren&th concrete #ith !ery hi&h durability and !ery lo# permeability is considered to

ha!e hi&h performance properties$ ,emonstrated that 50;a @"000 psi3 hi&h

performance concrete for brid&es could be economically made #hile meetin&

durability factors for air-!oid system and resistance to chloride penetration$

1$$1$1 S!%ie"$ Fe!$&re' of HPC416

i&h Compressi!e stren&th

Do# #ater-binder ratio

Reduced flocculation of cement &rains

Wide ran&e of &rain si>es

,ensified cement paste

No bleedin& homo&eneous mix

Dess capillary porosity

,iscontinuous pores

Stron&er transition >one at the interface bet#een cement paste and

a&&re&ate

Do# free lime content

Endo&enous shrin(a&e

o#erful confinement of a&&re&ates

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Dittle micro-crac(in& until about @-A0G of fc(

Smooth fracture surface

Fi&$ 1$1 i&h erformance Concrete is often used in brid&es and tall buildin&s

1$$2 High S$re"g$h Co"#re$e416

)he definition of hi&h stren&th chan&es o!er the years as concrete stren&th used in the

field increases$ )his publication considers hi&h-stren&th concrete SC3 to ha!e a

stren&th si&nificantly beyond #hat is used in normal practice$ For example" today

about H0G of ready mixed concrete has a 2I-day specified compressi!e stren&th

ran&in& from 20;a 000 psi3 to 50;a @000 psi3" #ith most ofit bet#een 2I;a

5000 psi3 and ;a 000 psi3$)herefore" SC considered here has desi&n stren&th

of at least A0;a 10"000 psi3$

)o put the concrete into ser!ice at much earlier a&e" for example openin& the

pa!ement at -days$

)o build hi&h-rise buildin&s by reducin& column si>es and increasin& a!ailable

space$

)o build the superstructure of lon& span brid&es and to enhance the durability ofbrid&e dec(s$

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)o satisfy the specific needs of special applications" such as durability" modulus of

elasticity and flexural stren&th$ Some of these applications include dams"

&randstand roofs" marine foundations" par(in& &ara&es and hea!y duty industrial

floors$ Note that hi&h stren&th concrete does not &uarantee durable concrete3$

i&h-stren&th concrete columns can hold more #ei&ht and therefore be made slimmer

than re&ular stren&th concrete columns" #hich allo#s for more useable space"

especially in the lo#er floors of buildin&s$ i&h-stren&th concrete is specified #here

reduced #ei&ht is important or #here architectural considerations call for small

support elements$ 9y carryin& loads more efficiently than normal-stren&th concrete"

hi&h-stren&th concrete also reduces the total amount of material placed and lo#er the

o!erall cost of the structure$

1.3.2.1 S(e#i!% )e$ho*' For )!+i"g HSC

Seedin&

Re!ibration

i&h speed slurry mixin&

=se of admixtures

%nhibition of crac(s

Sulphur impre&nation

=se of cementitious a&&re&ate

See*i"g,)his in!ol!es addin& a small percenta&e of finely &round" fully hydrated

ortland cement to the fresh concrete mix$ )his method may not hold much promise$

Re-ir!$io",Concrete under &oes plastic shrin(a&e$ ;ixin& #ater creates continuous

capillary channels" bleedin& and #ater accumulates at some selected places reducin&

stren&th of concrete$ Controlled re!ibration remo!es all these defects and increases

the stren&th of concrete$

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High S(ee* S%&rr/ )i0i"g,%t in!ol!es the ad!anced preparation of cement #ater

mixer #hich is then blended #ith a&&re&ate to produce concrete$ i&her compressi!e

stren&th obtained is attributed to more efficient hydration of cement particle and #ater

achie!ed in the !i&orous blendin& of cement paste$

U'e of A*i0$&re', =se of #ater reducin& a&ents are (no#n to produce increase

compressi!e stren&th$

I"hii$io" of Cr!#+', Replacement of 2-G of fine a&&re&ate by polythene or

polystyrene JlentculesK 0$02 mm thic( and -5 mm in diameter results in hi&her

stren&th$ )hey appear to acts as crac( arresters #ithout re'uirin& extra #ater for

#or(ability$

S&%(h&r I(reg"!$io",Satisfactory hi&h stren&th concrete ha!e been produced by

impre&natin& lo# stren&th porous concrete by sulphur$ )he process consist of moist

curin& the fresh concrete specimen for 25 hours" dryin& them at 1200 C for 25 hours"

immersin& the specimen in molten sulphur under !acuum for 2hrs and then releasin&

the !acuum and soa(in& them for an additional hour for further infiltration of sulphur$

)he sulphur infiltrated concrete has &i!en stren&th up to I;a$

U'e of Cee"$i$io&' Aggreg!$e,%t has been found that use of cementitious a&&re&ate

has yielded hi&h stren&th$ Cement fondu is a (ind of clin(er$ )his &lassy clin(er #hen

finely &round results in a (ind of cement$ When coarsely crushed" it ma(es a (ind of

a&&re&ate (no#n as L/D/M$ =sin& /D/ as a&&re&ate stren&th up to 12;a has

been obtained #ith #?c ratio 0$2$

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Fi&$1$5 .$. Flyo!er at ;umbai usin& i&h erformance Concrete

1.3.3 Re!#$i-e Po*er Co"#re$e RPC416

Reacti!e o#der Concrete RC3 is the last step in the de!elopment of so-called hi&h

performance concrete C3$ )he stren&th of this type of concrete is usually abo!e

120 N?mm2$ %ts name" reacti!e po#der concrete is actually only a more precise

expression than the name used in technical literature - =C - =ltra i&h

erformance Concrete" because to ma(e this concrete" !ery fine" reacti!e dry

components li(e crushed silica sand" micro-silica" fly ash etc$ #ith a &rain si>e of 00

0"2Om are used$ )he production of this (ind of concrete is impossible #ithout

special (no#led&e of the used components and manufacturin& technolo&y and curin&$

)echnical literature claims that RC can reach !alues of stren&th as hi&h as I00

N?mm2 #ith !ery lo# !alue of #?c ratio$

Defi"i$io" of RPC

Reacti!e o#der Concrete RC3 is a de!elopin& composite material that #ill allo#

the concrete industry to optimi>e material use" &enerate economic benefits" and build

structures that are stron&" durable" and sensiti!e to en!ironment$

1.3.3.1 RPC Pro(er$ie'

1$ Compressi!e Stren&th* =p to 120"000 psi 200 to I0;a3

2$ 1"000 psi 100;a3 or &reater 25 hours after initial set$



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$ )ensile Stren&th* 000 to A000 psi 20 to 0;a" t#ice as stron& as normal

concrete in compression3

5$ @-1;a tensile stren&th after first crac(in&$

$ Flexural Stren&th* P15000 psi 100;a3 flexural stren&th at first crac(in& is

hi&her than ultimate flexural stren&th of normal concrete$

@$ Qoun&Ms ;odulus 0 to A /

A$ Fracture ener&ies ran&in& from 1"000 to 50"000 .?m plastic failure rather

than brittle3

1.3.3.2 A((%i#!$io" of RPC

1$ RCMs properties" especially its hi&h stren&th characteristic su&&ests the

material mi&ht be &ood for thin&s needin& lo#er structural #ei&ht" &reater

structural spans" and e!en in seismic re&ions" it outperforms normal concrete$

9elo# are a fe# examples of real-#orld applications" thou&h the future

possibilities are endless$

2$ First brid&e that used RC #as a pedestrian brid&e in Sherbroo(" Buebec"

Canada$ "000 psi P20;a3 %t #as used durin& the early days of RC

production$ as prompted brid&e buildin& in North /merica" Europe"

/ustralia" and /sia$

$ ortu&al has used it for sea#all anchors

5$ /ustralia has used it in a !ehicular brid&e

$ France has used it in buildin& po#er plants

@$ Bin&hai-)ibet Rail#ay 9rid&e

A$ Sha#nessy Di&ht Rail )ransit Station$



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Fi& 1$ /pplications of RC

9asically" structures needin& li&ht and thin components" thin&s li(e roofs for

stadiums" lon& brid&e spans" and anythin& that needs extra safety or security such as

blast resistant structures$

1.3.4 Se%f Co(!#$i"g Co"#re$e

Self-compactin& concrete #as first de!eloped in 1HII to achie!e durable concrete

structure$

Self-compactin& concrete #as defined as follo#s at the three sta&es of concrete$

1$ Fresh* self-compactable

2$ Early a&e* a!oidance of initial defects

$ /fter hardenin&* protection a&ainst external factors

Self-compactin& concrete has e!ol!ed as an inno!ati!e technolo&y" capable of

achie!in& the status of bein& an understandin& ad!ancement in the field of concrete

technolo&y$ No !ibration is necessary for SCC #hich can flo# around obstructions"

encapsulate the reinforcement and fill up the form#or( completely under its o#n self



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#ei&ht$ With re!olutionary de!elopment" the construction en&ineer is no# reli!ed of

t#o annoyin& problems*

1$ )he difficulty in ensurin& throu&h compaction employin& uns(illed labour$

2$ )he necessity deal #ith repairs and ma(in& &ood finish #or(

)he reduce man po#er re'uired for castin& and finishin& leads to increase in the

speed of construction$ SCC compacts by itself #ithout the need of !ibration$

Enhanced fillin& capacity of hi&hly con&ested structural members" impro!ed health

and safety at site" faster construction time" reduced form#or(" less manpo#er"

reduced e'uipment cost" li&hter and more slender structure and impro!ed durability

are the ad!anta&es of SCC$

9y the early 1HH0Ms".apan has de!eloped and used SCC that does not re'uire !ibration

to achie!e full compaction$ 9y the year 2000" the SCC has become popular in .apan

for prefabricated products and ready mixed concrete$

SCC can be classified in to three types*

1$ o#der type SCC

2$ :iscosity a&ent type SCC

$ Combination type SCC

1.4FRC FI5RE REINFORCED CONCRETE

%n con!ectional concrete" micro crac(s de!elop e!en before loadin& because of dryin&

shrin(a&e and other causes of !olume chan&e$ When the structure is loaded" the micro

crac(s open up and propa&ate$ )he de!elopment of such micro-crac(s is the main

reason of inelastic deformation in concrete$

)he #ea(ness can be remo!ed by inclusion of small" closely spaced and uniformly

dispersed fibres in concrete$ )he addition of fibres in concrete substantially impro!es

its static and dynamic properties$ )hese fibres offer increased resistance to crac(



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&ro#th" throu&h a crac( arrestin& mechanism and impro!e tensile stren&th and

ductility of concrete$

Fibre reinforced concrete FRC3 can be defined as a composite material consistin& of

concrete and discontinuous" discrete" uniform dispersed fine fibres$ )he continuous

meshes" #o!en fabrics and lon& #ires or rods are not considered to be discrete fibres$

)he inclusion of fibres in concrete and shotcrete &enerally impro!es material

properties li(e ductility" flexural" stren&th" tou&hness impact resistance and fati&ue

stren&th$ )here is little impro!ement in compressi!e stren&th$ )he type and amount of

impro!ement is dependent upon the fibre type" si>e" stren&th and confi&uration and

amount of fibre$

Se!eral different types of fibres ha!e been used to reinforce the cement- based

matrices$ )he choice of fibres !aries from synthetic or&anic materials such as

polypropylene or carbon" synthetic inor&anic such as steel or &lass" natural or&anic

such as cellulose or sisal to natural inor&anic asbestos$ Currently the commercial

products are reinforced #ith steel" &lass" polyester and polypropylene fibres$ )he

selection of the type of fibres is &uided by the properties of the fibres such as

diameter" specific &ra!ity" youn&Ms modulus" tensile stren&th etc$ and the extent these

fibres affect the properties of the cement matrix$

%n relation to the elastic modulus" fibres are di!ided into t#o types*

)hose #here the elastic modulus of fibres is less than the elastic modulus of the

matrix* i$e$ Cellulose fibre" polypropylene fibre" poly acrylonitrile fibre" etc$

)hose #here the elastic modulus of fibres is &reater than the elastic modulus of

the matrix* i$e$ lass fibre" steel fibre" carbon fibre" aramid fibre" asbestos fibres"

etc$ ;any of the current applications of fibre reinforced concrete in!ol!e the use

of fibres ran&in& around 1$0 per cent by !olume of concrete$



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Fi&$ 1$@ )ypical Stress-Strain Cur!es For Fibre-Reinforced Concrete 4116

1.4.1 A*-!"$!ge' of FRC

Reduction in shrin(a&e and crac(in&$

%mpro!ement in bond stren&th$

Enhancement of fati&ue stren&th and endurance limit$

9etter tou&hness$

Do#er permeability of concrete$

1.4.2 A((%i#!$io" of FRC

P!-ee"$ !"* F%oor', )he most extensi!e use of FRC has been for pa!ements"

floors and o!erlays to ta(e ad!anta&e of increased stren&th" reduced crac(in& and

thic(ness reduction$



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6!$er Re$!i"i"g S$r$&re,

resultin& in #ater ti&htness$ )he steel fibre concrete has been successfully used in

the repair of spillin& basin at )arbela ,am in a(istan$

5%!'$ Re'i'$!"$ S$r$&re, )he blast #a!e #ill cause complex stressin& of

structure in compression" tension and shear$ Fibres in con+unction #ith

con!entional reinforcement pro!ide the necessary stren&th to structure to resist

blast$

Pre#!'$ Pro*$', )he FRC can also be used for the fabrication of precast

products li(e pipes" boats" beams" #all panels" stair case steps" roof panels"

manhole co!ers etc$

6e!ri"g S&rf!#e $o E0i'$i"g 5ri*ge'?C&%-er$, FRC has been used as a #earin&

surface to existin& brid&es and cul!erts in areas especially troubled by de&radation

caused throu&h abrasion by studded tyres$

Re(!ir' !"* Reh!i%i$!$io" 6or+', FRC is cohesi!e and easy to #or( pro!ide

fibres are thorou&hly mixed in the cement matrix$ %t is an ideal material for repair

and rehabilitation #or(s$

1.7 TYPES OF FI5RES

Natural Fibre$

Steel Fibre$

lass Fibre$

Carbon Fibre$

Synthetic Fibre$

1.7.1 S$ee% Fire

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Steel fibres ha!e been used in concrete since the early 1H00s$ )he early fibres #ere

round and smooth and the #ire #as cut or chopped to the re'uired len&ths$ )he use of

strai&ht" smooth fibres has lar&ely disappeared and modern fibres ha!e either rou&h

surfaces" hoo(ed ends or are crimped or undulated throu&h their len&th$ ;odern

commercially a!ailable steel fibres are manufactured from dra#n steel #ire" from slit

sheet steel or by the melt-extraction process #hich produces fibres that ha!e a

crescent-shaped cross section$ )ypically steel fibres ha!e e'ui!alent diameters based

on cross sectional area3 of from 0"1 mm to 2 mm and len&ths from A to A mm$

/spect ratios &enerally ran&e from 20 to 100$ /spect ratio is defined as the ratio

bet#een fibre len&th and its e'ui!alent diameter" #hich is the diameter of a circle

#ith an area e'ual to the cross-sectional area of the fibre3$

Steel Fibre )echnolo&y is #idely recommended in Shotcretin& of )unnels" Slope

Stabili>ation" ;ine Roof Support" re Cast for )unnel Dinin&s" Foundation Slabs"

Roads" 9rid&es" Run#ays" )axi#ays" Factory Floorin&" re Cast #alls" Concrete

ipes" ;anhole Co!ers" and !arious other concrete applications$

Fi&$ 1$A ,ifferent )ypes of Steel Fibre

A*-!"$!ge' of S$ee% Fire

Steel Fibres result in more homo&enous mix in concrete$

Flexural strain capacity is enhanced

/dds ductility to concrete

Controls crac(s

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.oint stability

Narro# +oint #idth

Shear load transfer

Fati&ue and impact resistance

ost crac( ductility

Reduces material consumption and sa!es cost

Don&er ser!ice life

9:; En&&$ Colle&e" :$:$Na&ar a&e 1I


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1.7.2 G%!'' Fire

%n the form first used" &lass fibres #ere found to be al(ali reacti!e and products in#hich they #ere used deteriorated rapidly$ /l(ali-resistant &lass containin& 1@G

>irconia #as successfully formulated in the 1H@0s and by 1HA1 #as in commercial

production in the =T$


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Fi&$1$I ,ifferent )ypes of lass Fibres

1.7.3 S/"$he$i# Fire

A variety of synthetic fibre materials have been developed since

1960s for use in fibre Reinforced concrete (FRC)s !hese include

fibres such as polypropylene" nylon" carbon" aramid" polyethylene"

acrylic and polyester #n current commercial and industrial concrete

applications synthetic fibres are typically added to concrete at very

lo$ dosa%e rates" typically in the ran%e of 006 to 0&' by volume

ynthetic fibre reinforced concrete (FRC) has found its lar%est

commercial use to date in slabs on %rade" floor slabs and stay*in*

place forms in multi*storey buildin% +Concrete #nstitute of Australia

&00,-

Fi%19.ifferent !ypes of ynthetic Fibres

1.7.4 N!$&r!% Fire



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Fi& 1$10 Classifications of Natural Fibres

Natural reinforcin& materials can be obtained at lo# cost and lo# le!els of ener&y

usin& local manpo#er and technolo&y$ =tili>ation of natural fibres as a form of

concrete reinforcement is of particular interest to less de!eloped re&ions #here

con!entional construction materials are not readily a!ailable or are too expensi!e$

Sisal-fibre reinforced concrete has been used for ma(in& roof tiles" corru&ated sheets"

pipes" silos and tan(s$

Elephant-&rass-reinforced mortar has been used for lo#-cost housin& pro+ects$ Wood-

cellulose fibre reinforced cement has commercial applications in the manufacture of

flat and corru&ated sheet and non-pressure pipes$

Natural fibres can be either =nprocessed or rocessed$

1. U"(ro#e''e* Fire

roducts made #ith unprocessed natural fibres such as coconut coir" sisal" su&arcane

ba&asse" bamboo" +ute" #ood and !e&etable fibres ha!e been tested in a number of

countries$ roblems ha!e been reported #ith the lon&-term durability of some of the

products$

)he properties of concrete made usin& unprocessed natural fibres depend on a number

of factors includin& the type and len&th of fibre as #ell as the !olume fraction$ )o



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sho# some impro!ement in mechanical properties" the minimum fibre content is of

the order of G by !olume$

2. Pro#e''e* Fire

Wood cellulose is the most fre'uently used natural fibre$ %t is most commonly

obtained usin& the Traft process$ )his process in!ol!es coo(in& #ood chips in a

solution of sodium hydroxide" sodium carbonate and sodium sulphide$ ,ifferent

&rades of #ood-cellulose fibre containin& more or less of the three main constituents"

cellulose" hemi cellulose and li&na can be obtained by bleachin&$

Wood-cellulose fibre has relati!ely &ood mechanical properties compared #ith many

man-made fibres such as polypropylene" polyethylene" polyester and acrylic$

,eli&nified cellulose fibre can be produced #ith tensile stren&ths up to approximately

2"0a from selected &rades of #ood" and usin& suitable pulpin& processes$ Fibre

tensile stren&ths of 00;a can be routinely obtained usin& a chemical pulpin&

process and the more common" less expensi!e" &rades of #ood$

Ce%%&%o'e N!$&r!% Fire

Wood cellulose is the most fre'uently used natural fibre$ %t is most commonly

obtained usin& the Traft process$ )his process in!ol!es coo(in& #ood chips in a

solution of sodium hydroxide" sodium carbonate and sodium sulphide$ ,ifferent

&rades of #ood-cellulose fibre containin& more or less of the three main constituents"

cellulose" hemicellulose and li&na can be obtained by bleachin&$

Wood-cellulose fibre has relati!ely &ood mechanical properties compared #ith manyman-made fibres such as polypropylene" polyethylene" polyester and acrylic$

,eli&nified cellulose fibre can be produced #ith tensile stren&ths up to approximately

2$0pa from selected &rades of #ood" and usin& suitable pulpin& processes$ Fibre

tensile stren&ths of 00;a can be routinely obtained usin& a chemical pulpin&

process and the more common" less expensi!e" &rades of #ood$



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Reduced #ear of toolin&" healthier #or(in& condition" and no s(in irritation$

)hermal recyclin& is possible #hile &lass causes problem in combustion furnaces$

ood thermal and acoustic insulatin& properties$

1.8 T/(e' of S&((%ee"$!r/ Cee"$i$io&' )!$eri!%'

)he most commonly used supplementin& cementitious materials?mineral admixtures

for achie!in& C are*

1$ Silica Fume

2$ 9FS round ranulated 9last Furnace Sla&3

$ R/ Rise us( /sh3

5$ Fly /sh

1.8.1 Si%i#! F&e

Silica fume also referred as micro silica or condensed silica fume is another material

that is used as an artificial po>>olanic admixture$ %t is a product resultin& from

reduction of hi&h purity 'uart> #ith coal in an electric arc furnace in the manufacture

of silicon or ferrosilicon alloy$ When 'uart> are sub+ected to 20000C reduction ta(es

place and Si< !apours &et into fuels$ %n the course of exit" oxidation ta(es place and

the product is condensed in lo# temperature >ones$ %n the course of exit" Silica fume

rises as an oxidised !apour" oxidation ta(es place and the product is condensed in lo#

temperature >ones$ When the silica is condensed" it attains non-crystalline state #ith

ultra-fine particle si>e$ )he super fine particles are collected throu&h the filters$ %t

cools" condenses and is collected in ba&s$ %t is further processed to remo!e impurities

and to control particle si>e$ Condensed silica fume is essential silicon dioxide Si


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Fi&$ 1$1 roduction of Silica Fume

Fi&ure 1$1 sho#s a smelter in the days before silica fume #as bein& captured for use

in concrete and other applications$ )he Jsmo(eK lea!in& the plant is actually silica

fume$ )oday in the =nited States" no silica fume is allo#ed to escape to the

atmosphere$ / schematic of silica fume production is sho#n in Fi&ure 1$15 and a

schematic of a smelter is sho#n in Fi&ure 1$15$ )he silica fume is collected in !ery

lar&e filters in the ba& house and then made a!ailable for use in concrete directly or

after additional processin&



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Fi& 1$15 roduction lant of Silica Fume

)able 1 Chemical Composition of Silica Fume in G

Si


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A*-!"$!ge' of Si%i#! F&e

i&h stren&th concrete made #ith silica fume pro!ides hi&h

abrasion?corrosion resistance$

Silica fume influences the rheolo&ical properties of fresh concrete" the

stren&th" porosity and durability of hardened mass$

Silica fume concrete #ith lo# #ater content is hi&hly resistant to penetration

of chloride ions$

)he extreme fineness of silica fume allo#s it to fill or pac( the microscopic

!oids bet#een cement particle and especially in the !oids at the surface of the

a&&re&ate particles #here the cement particles cannot fully co!er the surface

of the a&&re&ate and fill the a!ailable space$

Silica fume can also be proportioned as a #ater reducer #ith the reduction in

#ater cementitious material ratio" so it is hydrophilic in nature" thus super

plastici>er demand for additional #ater can be minimised$

Silica fume reduces bleedin& se&re&ation of fresh concrete si&nificantly$ )his

effect is caused due to hi&h surface area$

i&hly durable concrete can be obtained by impro!in& the electrical

resisti!ity of concrete by the addition of silica fume$

1.8.2 GG5S Gro&"* Gr!"&%!$e* 5%!'$ F&r"!#e S%!g

roundranulated9lastfurnacesla&9S3isa by-productformanufactureofpi&ironand obtainedthrou&hrapidcoolin&by #ateror 'uenchin&molten sla&$erethemolten

sla& is

produced#hichisinstantaneouslytappedand'uenchedby#ater$)hisrapid'uenchin&

ofmolten sla& facilitatesformationofJranulatedsla&K$ roundranulated9lastfurnace

Sla& 9S3 is processedfrom ranulated sla&$

)hereplacementofcement#ith9S#illreducetheunit#atercontent necessary

toobtainthe



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sameslump$)hisreductionof#atercontentismorepronounced#ithincreaseinsla&

contentand

alsoonthefinenessofsla&$)hisisbecauseofthesurfaceconfi&urationandparticle shape

ofsla& bein&differentthancementparticle$Surfacehydrationofsla&issli&htly

slo#erthanthatof cement$Reductionofbleedin& isnotsi&nificant#ithsla&

of5000cm2?&finenessbutsi&nificant #hen sla&fineness of @000 cm2?&andabo!e$

round&ranulatedblastfurnacesla&no#adaymostlyusedin%ndia$Recentlyformarine out

fall#or(at9andra";umbai$%thasusedto replace cementtoaboutA0G$Soithasbecome

more popularno# aday$

Fi&$ 1$1roundranulated 9last Furnace Sla& 9S3

1.8.2 RHA Ri'e H&'+ A'h

Rice hus( ash is obtained by burnin& rice hus( in controlled manner #ithout causin&

en!ironmental pollution$ When it is properly brunt it has hi&h Si>olanic

characteristics and contributes to hi&h stren&th and hi&h impermeability of concrete$

Rice hus( ash essential consists of amorphous or non-crystalline silica #ith about I-

H0G cellular particle" G carbon and 2G T2


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po>>olanic material to &i!e almost the same properties as that of micro silica$ it

&reatly enhances the #or(ability and impermeability of concrete$

Fi

&$ 1$15 R/ Rise us(/sh3

1.8.4 F%/ A'h

Fly ash is the residue from the combustion of pul!eri>ed coal collected by the

mechanical or electrostatic precipitator from the flue &ases of thermal po#er plants$

%t consists mainly of spherical &lassy particles ran&in& from 1 to 10 micron in

diameter of #hich the bul( passes throu&h a A micron %S sie!e$ )he fly ash obtained

from electrostatic precipitators may ha!e a specific surface of about 00 to 000

cm2?&m$ %n =$T$ the fly ash is referred as pul!erised fuel ash F/3$ Fly ash is the

most #idely use po>>olanic material all o!er the #orld$

)he fly ash contains silicon oxide" aluminium oxide" unburnt carbon but the amount

of calcium oxide is cPrsiderably less$ )he carbon content in fly ash should be as lo#

as possible #hereas the silica content should be as hi&h as possible$



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Fi&$ 1$1 Fly ash

Ch!($er 2

RE9IE6 OF LITERATURE

2.1 EARLIER RESEARCHES

Some of the early research #or(s are completed to de!elop concrete by usin&

different types of po>>olonic materials li(e Fly /sh" R/" Silica Fume etc$ #ith the

replacement of cement usin& super plastici>er$ ;any fibres ha!e been used for

concrete reinforcement and some are #idely a!ailable for commercial application$

)hey include steel" &lass"natural cellulose" carbon" nylon" and polypropylene" amon&

others #hich are addin& #ith po>>olonic material to de!elop concrete$ )he literature

bein& re!ie#ed is &i!en under$

2.2 LIST OF LITERATURE TA5LE

Sr.

No.A&$hor N!e Ye!r Ti$%e of Re'e!r#h P!(er

1$ Qo&endran et al$ 1HIAEffect of silica fume and admixtures on

properties of concrete$

2$ room 1HH.ournal of materials in ci!il

en&ineerin&?No!ember 2000

$ amous and El-a#ary 1HH5.ournal of materials in ci!il

en&ineerin&?No!ember 2000

5$ /uchey and ,utta [email protected] of materials in ci!il

en&ineerin&?No!ember 2000U

$ Naaman et al$ [email protected] of materials in ci!il

en&ineerin&?No! 2000

@$ Shanna& 20009eha!iour study of natural po>>olana

and silica fume$

A$

aulo 9$ Cachim a"V"

.oa'uim /$ Fi&ueiras b"

aulo /$/$ ereira c

2001Fati&ue beha!iour of fibre-reinforced

concrete in compression

I$;oe ;oe)h#ea and Tin

Diaob2002

,urability of bamboo &lass fibre

reinforced polymer matrix hybrid

composites$



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22$ $ :inaya&am 2012

Experimental %n!esti&ation on i&h

erformance Concrete usin& Silica

Fume and Super plastici>er$

2.3 LITERATURE RE9IE6

Co"#re$e Rei"for#ee"$ i$h Re#/#%e* Fire' / H!o&' !"* E%:

H!!r/1;;4 456

)hey studied the use of chic(en feathers from poultry processin& as fibres in concrete$

)hey conducted flexural" splittin&" and compressi!e tests on a ortland cement

concrete mix #ith a #ater-to-cement ratio of 0$@ and fibre !olume fractions of 1" 2"

and G$ Do# #or(ability of fresh concrete #as obser!ed so a pro&ressi!ely lar&er

amount of super plastici>er had to be added #ith the increase of Vf$ / moderate

increase in the flexural stren&th #as obser!ed for the 1G Vfreinforcement at 15 and

2I days" and a decrease in the stren&th for the 2 and G reinforcements$ %n the

compressi!e and splittin& tensile tests" the stren&ths decreased sharply as the fibre

dosa&e rate increased$ )he authors attributed the ad!erse effect to the se!ere decay of

the feather fibres in concrete$

Effe#$ o" Si%i#! F&e !"* )e$!+!o%i" Coi"!$io" o" Co"#re$e /

9i+!' Sri-!'$!-!1< R!+e'h =&!r2< Ag!r!% 9.C312

4106

)hey carried out experimental research on Effect of Silica Fume and ;eta(aolin

combination on concrete$ 9y addition of some po>>olanic materials" the !arious

properties of concrerte!i>" #or(ability" durability" stren&th" resistance to crac(s and

permeability can be impro!ed$ Silica fume is (no#n to impro!e both the mechanical

characteristics and durability of concrete$ )he principle physical effect of silica fume

in concrete is that of filler" #hich because of its fineness can fit into space bet#een

cement &rains in the same #ay that sand fills the space bet#een particles of coarse

a&&re&ates and cement &rains fill the space bet#een sand &rains$ /s for chemical



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reaction of silica fume" because of hi&h surface area and hi&h content of amorphous

silica in silica fume" this hi&hly acti!e po>>olana reacts more 'uic(ly than ordinary

po>>olana$ ;eta(aolin is also one of such #aste? non - con!entional material #hich

can be utili>ed beneficially in the construction industry$ )his paper presents the

results of an experimental in!esti&ations carried out to find the suitability of silica

fume and meta(aolin combination in production of concrete$ )he optimum doses of

silica fume and meta(aolin in combination #ere found to be @G and 1G by #ei&ht3

respecti!ely" #hen used as part replacement of ordinary portland cement$

)hey conclude that the optimum dose of Silica fume and ;eta(aolin in combination

is found to be @G and 1G by #ei&ht3 respecti!ely at both A and 2I day compressi!e

stren&th$

)he slump is found to decreases #ith increase in ;eta(aolin content at all the Silica

fume contents considerably

Fire Rei"for#e* Co"#re$e &'i"g *oe'$i# !'$e (%!'$i# !' Fire' /

R. =!"*!'!/1!"* R. )&r&ge'!"24H6

Fibre Reinforced Concrete FRC3 is a composite material consistin& of cement based

matrix #ith an ordered or random distribution of fibre #hich can be steel" nylon"

polythene etc$ )he addition of steel fibre increases the properties of concrete" !i>$"

flexural stren&th" impact stren&th and shrin(a&e properties to name a fe#$ / number

of papers ha!e already been published on the use of steel fibres in concrete and a

considerable amount of research has been directed to#ards studyin& the !arious

properties of concrete as #ell as reinforced concrete due to the addition of steel fibres$

ence" an attempt has been made in the present in!esti&ations to study the influence

of addition of polythene fibres domestic #aste plastics3 at a dosa&e of 0$G by

#ei&ht of cement$ )he properties studied include compressi!e stren&th and flexural

stren&th$ )he studies #ere conducted on a ;20 mix and tests ha!e been carried out as

per recommended procedures of rele!ant codes$ )he results are compared and

conclusions are made$



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Fi& 2$2 Comparison of 2I days cube left3 and cylinder ri&ht3 compressi!e stren&th

test results$

Effe#$ of Si%i#! F&e o" Co"#re$e / Pree$i P. P!$e%< E%i?!e!$h

George< Dee(! A. Si"h!2>>@ 4I6

)he stren&th of concrete at early a&es is a considerable si&nificance in recent years

due to se!eral specific re'uirements of the modern construction techni'ues$o#e!er"

silica fume concrete are (no#n to ha!e early a&e stren&th and there ha!e been many

efforts to predict to impro!e this in recent years$)he #or( #as carried out for t#o

&rades ;20 and ;0 of concrete$ For the &rades of concrete the cement content"

sand" &rit" coarse a&&re&ate and #?c ratio is (ept constant$


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Fi& 2$ :ariation of Compressi!e Stren&th left3 and Flexural Stren&th ri&ht3 #ith

Silica Fume ercenta&e$

S$&*/ o" eh!-io&r o" N!$&r!% Fire Co"#re$e Co(o'i$e' &'i"g

)e#h!"i#!% S$re"g$h )i#ro'$r$&re Pro(er$ie' /

).Shi-r!B!


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/t all the curin& a&es" both the natural fibres such as coir and su&arcane fibres

enhance all the three mechanical stren&th properties such as compressi!e stren&th"

splittensile stren&th" modulus of rupture and flexural erformance$

)hou&h the natural fibres enhance the stren&th properties at earlier curin& a&es" the

rate of increments are lo#er than con!entional concrete specimen at later curin&

a&es$

SE; and E,S analyses confirmed that the boundary of fibrematrix transition

>one ha!e excellent adhesion$ )he impre&nation of calcium content on the fibre

#alls sho#ed better stren&th enhancement$

9oth the natural fibre reinforced concretes #ere less susceptible a&ainst sulphate

attac( in terms of mass loss and compressi!e stren&th deterioration$ Since the

difference obser!ed #as lar&e" application of natural fibre reinforced concrete

#ould be limited in marine areas$

Co"#re$e Rei"for#ee"$ i$h Re#/#%e* Fire' / Ahe/ !"*

D&$$!1;;8416

Conducted a study on the use of recycled ,E fibres in concrete under extreme

free>e-tha# conditions$ ,E is a plastic material often used for ma(in& containers

for food and household chemicals$ )he fibres used in the study #ere cut from mil(

containers #ith a typical dimension of 1HI-mm lon&" 1$@-mm #ide" and 1-mm

thic("and their tensile stren&th #as 5;a$ / 2I;a compressi!e stren&th concrete

mix #as used and the fibres added #ere at 0$1" 0$2" and 0$5G by !olume$ /t 2I days

after castin&" the cylinder specimens #ere sub+ected to the free>e-tha# cycles of

repeated 1-h coolin& at 220AC follo#ed by a 1-h tha#in& at 20AC$ )he dynamic

modulus of elasticity of the specimens #as monitored to indicate the internal dama&e$

)he authors found that it #as feasible to use recycled ,E fibres as a secondary

reinforcement for temperature and shrin(a&e influences in concrete structures

sub+ected to extreme free>e-tha# conditions$ )he recycled ,E fibre reinforced

specimens pro!ided an e'ual or hi&her resistance to free>e-tha# than the control

9:; En&&$ Colle&e" :$:$Na&ar a&e H


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indicated that the addition of silica fume impro!es the properties of concrete &i!in&

hi&h compressi!e stren&th" hi&h stress and strain" stresses carried by the concrete

increased by 5@$"@I$I"@$1"A$3G also the strain increased by I$"HA$I"2$I"223G

for silica fume percenta&es "10"1"203G$ for monotonic loadin&" and stresses

increased by 55$5"@I$"@$A"@$3G and strain increased by 5$I"@I$5"1$"2@$3G

for the same percenta&es under repeated loads$ Compressi!e stren&th" dissipated

ener&y" and modulus of elasticity also increased #ith increasin& silica fume

percenta&e$

Co"#re$e Rei"for#ee"$ i$h Re#/#%e* Fire' / N!!!" e$ !%.

1;;8 4A6

e in!esti&ated the effect of polypropylene fibre s from carpet #aste on the flexural

and compressi!e beha!iour of concrete and mortar$ )he fibres #ere obtained from

shredded carpet bac(in&$ )he fibre len&th ran&ed from near 0 po#der3 to about 2

mm" and about 50G of the fibre #ere shorter than mm$ Fi!e fibre !olume fractions

#ere used* 0$1" 1$0" 1$" 2$@" and $HG$ )he matrices included concrete #ith coarse

a&&re&ates" mortar #ith re&ular ri!er sand" and mortar #ith !ery fine silica sand$ )ype

% ortland cement #as used #ith a #ater-to-cement ratio of 0$@00$@$ )he study

re!ealed that the #aste polypropylene fibres #ere more efficient in matrices #ith finer

a&&re&ates$ )here #as a si&nificant impro!ement in the flexural properties #ith a

2$@G by !olume fibre reinforcement$ No si&nificant impro!ement in bendin& #as

obser!ed for Vfbelo# 1$G" and a sli&ht decrease in performance #as obser!ed #hen

Vfincreased from 2$@ to $HG$ )he compressi!e stress strain beha!iour of concrete

#as not impro!ed by the polypropylene fibres$

Cri$i#!% O'er-!$io" fro $he Li$er!$&re

Not properly defined the use of cellulose fibre #ith silica fume$

)he maximum G of silica fume to be used$

=se of silica fume #ith super plastici>er increases #or(ability and stren&th of

concrete$



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)able 2 one" that is Yone-%" Yone-%%" Yone-%%%" Yone-%:$ /lso in case of coarse a&&re&ate

maximum 20 mm coarse a&&re&ate is suitable for concrete #or($ 9ut #here there is



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no restriction 50 mm or lar&e si>e may be permitted$ %n case of close reinforcement

10mm si>e also used$

Fi& 5$1 Fine /&&re&ate and Coarse /&&re&ate

4.1.3 6!$er

Water fit for drin(in& is &enerally considered fit for ma(in& concrete$ Water should be

free from acids" oils" al(alis" !e&etables or other or&anic %mpurities$ Soft #aters also

produce #ea(er concrete$ Water has t#o functions in a concrete mix$ Firstly" it reacts

chemically #ith the cement to form a cement paste in #hich the inert a&&re&ates are

held in suspension until the cement paste has hardened$ Secondly" it ser!es as a

!ehicle or lubricant in the mixture of fine a&&re&ates and cement$

4.1.4 S&(er P%!'$i#i?er

)here are t#o types of admixtures i$e$ ;ineral admixtures and Chemical admixtures$

1 )i"er!% A*i0$&re'

Silica fume

round &ranulated blast furnace sla&

Rice hus( ash

Fly ash



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2 Chei#!% A*i0$&re

/cceleratin& admixture

Retardin& admixture

Water-reducin& admixture

/ir enterin& admixture

Super- plastici>in& admixture

Po%/#!ro0/%!$e S&(er P%!'$i#i?er

C-D is a hi&h performance" 100G poly carboxylate based polymer" specifically

de!eloped based polymer" specifically de!eloped as an effecti!e dispersant" fluid fire

and hi&h ran&e #ater reducin& a&ent for concrete and other mineral materials$ C-D is

a neutral concentrate &rade it is mainly used as a ra# material to produce differenttypes of hi&h performance #ater reducers for tar&eted industrial$ %t complies #ith

/S); C 5H5" )ype F specifications$

U'e'

C-D is a plant- added super plastici>er that is formulated to impart impro!ed

#or(ability to the concrete and to achie!e hi&h early compressi!e stren&th as

re'uired by precast industry$

C-D can be applied in #ide !ariety industry" such as the production of self-

consolidatin& concrete in precast industry" con!entional concrete production

industry e!en #ith lo# #?c ratios #hile maintainin& normal le!els of #or(ability

and so on$

A*-!"$!ge'

13 roduces concrete #ith hi&h le!els of #or(ability #ithout se&re&ation$



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23 ro!ides si&nificantly hi&her stren&ths and normal set time$

3 as excellent concrete rheolo&y and handlin& properties$

53 ro!ide impro!ed finish ability and surface finishes$

3 as superior air entrainment control$

@3 ro!ides standard #ater reduction at normal addition rates and si&nificant

#ater reduction at hi&her addition rates$

A3 as no chloride ions and non-corrosion to steel bar$

I3 %mpro!e the frost resistance and carbonation resistance of the concrete$ Do#er

dryin& shrin(a&e of the concrete by 20G or more compared to naphthalene-

based admixture$

9:; En&&$ Colle&e" :$:$Na&ar a&e 5A


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4.2 EPERI)ENTAL SET UP

4.2.1 Te'$ o" Fre'h Co"#re$e

ear" discussed the role of $ater and the uantity of $ater reuired

for chemical combination $ith cement and to occupy the %el pores

2e have seen that the theoretical $ater3cement ratioreuired for

these t$o purposes is about 0,4 but for hi%h performance concrete

this ration isdifferent 5se of $ater3cement ratio more than this" $ill

result in capillary cavities and less than this" $ill result in

incomplete hydration and also lac7 of space in the system for the

development of %el

4.2.2 )e!'&ree"$ of 6or+!i%i$/ / Te'$'

!he follo$in% tests are commonly employed to measure $or7ability

a) lump !est

b) Compactin% Factor !est

c) Flo$ !est

d) 8elly all !est

e) :ee ee Consistometer !est

Co(!#$i"g F!#$or Te'$

Compactin& factor of fresh concrete is done to determine the #or(ability of fresh

concrete by compactin& factor test as per %S* 11HH 1HH$ )he apparatus used is

Compactin& factor apparatus$



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)he compactin& factor test is defined as the ratio of the mass of the concrete

compacted in the compaction factor apparatus to the mass of the fully compacted

concrete$ %t in!ol!es droppin& a !olume of concrete from one hooper to another and

measurin& the !olume of concrete in the final hooper to that a fully compacted

!olume$ )he results of the compaction factor test can be correlated to slump" throu&h

the relationship is not linear$ )his test is difficult to run in the field and is not practical

for lar&e a&&re&ates compared to the slump test" the apparatus is bul(y and a balance

is re'uired to perform$

S(e#ifi#!$io"

%t consists of t#o ri&id conical hoopers and a cylinder mounted on a ri&id metal frame$)he lo#er openin& of the hoopers are fitted #ith hin&ed trapdoors ha!in& a 'uic(

release catches$ / circular metal plate is pro!ided to co!er the top of the cylinder$

Supplied complete #ith one plasterMs tro#el and tampin& rod" 1@mmdiaZ @00mm

lon&" both end rounded$

Fi&$ 5$2 Compactin& Factor /pparatus rocedure

9:; En&&$ Colle&e" :$:$Na&ar a&e 5H


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%3 lace the concrete sample &ently in the upper hopper to its brim usin& the hand

scoop and le!el it$

%%3 Co!er the cylinder

%%%3


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1 Compressi!e test$(#*;16/ 19;9)

& )ensile stren&th test$(#*;16/ 19;9)

$ Flexural stren&th test$%S-I1@-1HHH3

5$2$$1 Co(re''i-e Te'$ %S 1@* 1HH3 416

Compression test is the most common test conducted on hardened

concrete" partly because itis an easy test to perform" and partly

because most of the desirable characteristic properties of concreteare ualitatively related to its compressive stren%th !he

compression test is carried out on specimens cubical or cylindrical in

shape e of )est Specimens\ )est specimens cubical in shape shall be 1Z 1Z 1 cm$ %f

the lar&est nominal si>e of the a&&re&ate does not exceed 2 cm" 10 cm cubes may be

used as an alternati!e$ Cylindrical test specimens shall ha!e a len&th e'ual to t#ice

the diameter$ )hey shall be 1 cm in diameter and 0 cm lon&$ Smaller test specimens

shall ha!e a ratio of diameter of specimen to maximum si>e of a&&re&ate of not less

than to 1" except that the diameter of the specimen shall be not less than A$ cm for

mixtures containin& a&&re&ate more than G of #hich is retained on %S Sie!e 5I0$

A((!r!$&'

)estin& ;achine \ )he testin& machine may be of any reliable type" of sufficient

capacity for the tests and capable of applyin& the load &radually$ )he permissible

error shall be not &reater than ] 2G of the maximum load$ )he testin& machine shall

be e'uipped #ith t#o steel bearin& platens #ith hardened faces$


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expressed to the nearest (& per s'$cm$ /!era&e of three !alues shall be ta(en as the

representati!e of the batch pro!ided the indi!idual !ariation is not more than ] 1G

of the a!era&e$


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appear at any section" not stron& enou&h to resist the stress #ithin the middle third"

#here the bendin& moment is maximum$ %t can be expected that the t#o point loadin&

#ill yield a lo#er !alue of the modulus of rupture than the centre point loadin&$ %$S$

1@-1HH" specifies t#o point loadin&$

A((!r!$&'

)he testin& machine may be of any reliable type of sufficient capacity for the tests and

capable of applyin& the load at the rate specified in belo#$ )he permissible errors

shall be not &reater than ] 0$G of the applied load #here a hi&h de&ree of accuracy is

re'uired and not &reater than ] 1$G of the applied load for commercial type of use$

)he bed of the testin& machine shall be pro!ided #ith t#o steel rollers" I mm indiameter" on #hich the specimen is to be supported" and these rollers shall be so

mounted that the distance from centre to centre is @0 cm for 1$0 cm specimens or 50

cm for 10$0 cm specimens$ )he load shall be applied throu&h t#o similar rollers

mounted at the third points of the supportin& span" that is" spaced at 20 or 1$ cm

centre to centre$ )he load shall be di!ided e'ually bet#een the t#o loadin& rollers"

and all rollers shall be mounted in such a manner that the load is applied axially and

#ithout sub+ectin& the specimen to any torsional stresses or restraints$


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approximately A (&?s' cm?min" that is" at a rate of loadin& of 500 (&?min for the 1$0

cm specimens and at a rate of 1I0 (&?min for the 10$0 cm specimens$ )he load shall

be increased until the specimen fails" and the maximum load applied to the specimen

durin& the test shall be recorded$ )he appearance of the fractured faces of concrete

and any unusual features in the type of failure shall be noted$

Fi&ure 5$5 Flexural )est /rran&ements

C!%#&%!$io"

)he flexural stren&th of the specimen shall be expressed as the modulus of rupture fb"

#hich" if LaM e'uals the distance bet#een the line of fracture and the nearer support"

measured on the centre line of the tensile side of the specimen" in cm" shall be

calculated to the nearest 0$ (&?s'$cm as follo#s*

fb7 p Vl? bd2

#hen LaM is &reater than 20$0 cm for 1$0 cm specimen" or &reater than 1$ cm for a

10$0 cm specimen" or

fb7 pVl? bd2

When LaM is less than 20$0 cm but &reater than 1A$0 cm for 1$0 cm specimen or less

than 1$ cm but &reater than 11$0 cm for a 10$0 cm specimen

Where"



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b 7 measured #idth in cm of the specimen"

d 7 measured depth in cm of the specimen at the point of failure"

l 7 len&th in cm of the span on #hich the specimen #as supported" and

p 7 maximum load in (& applied to the specimen$

%f LaM is less than 1A$0 cm for a 1$0 cm specimen" or less than 11$0 cm for a 10$0 cm

Specimen" the results of the test shall be discarded$

5$2$$ S(%i$$i"g Te"'i%e S$re"g$h%S I1@-1HHH3

)he concrete cylinder specimen may be tested for A days and 2I days and shall be

immerse in #ater for at least 25 hours before test$ / concrete cylinder si>e 10mm

diameter and 00mm hei&ht is sub+ected to action of compressi!e force alon& t#o

opposite ed&es$ )he cylinder is placed #ith its axis hori>ontal bet#een the platens of a

testin& machine" and the load is increased until failure by splittin& alon& the !ertical

diameter ta(es place$ 9y applyin& the force in this manner" the cylinder is sub+ected to

compression near the loaded re&ion and the lar&er portion correspondin& to depth is

sub+ected to a uniform tensile stress actin& hori>ontally$ %t is estimated that the

compressi!e stress is actin& for 1?@ depth and the remainin& ?@ depth is sub+ected to

tension$

Fi&ure 5$Splittin& )ensile Stren&th )estin& on Cylinders$

9:; En&&$ Colle&e" :$:$Na&ar a&e @


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4.2.3.4 Sor($i-i$/ Te'$

)he Sorpti!ity of concrete is a 'uantity that measures the unsaturated flo#

of fluids into the concrete 4all" 1HIH6$ Sorpti!ity is a measure of the

capillary forces exerted by the pore structure causin& fluids to be dra#n in

to the body of the material$ While theoretically possible to consider the

flo# in any &eometry" it is too mathematically complex to be of any

practical use except #here there are one dimensional flo# conditions$

For one dimensional flo#" it can be stated that 4all" 1HIH6*

%7 St1?2

Where i is the cumulati!e #ater absorption per unit area of inflo# surface"

S is the Sorpti!ity and t is the elapsed time$ %n a lab situation #here the

concrete sample can be dried consistently and the flo# conditions can be

#ell defined" is it relati!ely easy to &et a &ood fit line usin& least s'uares

re&ression #hen plottin& i !s$ the s'uare root of time$ / field Sorpti!ity

test has also been de!eloped 4,eSou>a" et al$" 1HH6$

,eterminin& the Sorpti!ity of a sample in the lab is a simple" lo#

technolo&y techni'ue illustrated in Fi&ure 10$ /ccordin& to the /S);

draft standard all that is re'uired is a scale" a stop#atch and a shallo# pan

of #ater$ )he sample is preconditioned to a certain moisture condition"

either by dryin& the sample for A days in a 0^C o!en or by dryin& for four

days at 0^C and then allo#ed to cool in a sealed container for three days$

)he sides of the concrete sample are sealed" typically #ith electricianMs

tape$ )he initial mass of the sample is ta(en and at time 0 is immersed to a

depth of -10 mm in the #ater$ /t selected times typically 1" 2" " 5" " H"

12" 1@" 20 and 2 minutes3 the sample is remo!ed from the #ater" the

stop#atch stopped" excess #ater blotted off #ith a damp paper to#el and

the sample #ei&hed$ %t is then replaced in the #ater and the stop#atch

started a&ain$ )he &ain in mass per unit area o!er the density of #ater is

9:; En&&$ Colle&e" :$:$Na&ar a&e A


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plotted !ersus the s'uare root of the elapsed time$ )he slope of the line of

best fit of these points i&norin& the ori&in3 is reported as the Sorpti!ity$

4.3EPERI)ENTAL PROGRA))E

)ETHEODOLOGY

)able$;2radeExperimentalro&ramme

rade of

Concrete

G of

Silica

Fume

=se

Gof

Cellulose

Fibre

=se

No$ of

Cubes

for

Comp$

)est

No$ of

9eams

for

Flexural

)est

No$ of

Cylinders

for Split

)ensile

)est

)otal

Specimen

for A

days )est

)otal

Specimen

for 2I

days

)est

)otal

Specimen

for @

days

)est

)27

AG 0$G H H H

AG 1$0G H H H

HG 0$G H H H

HG 1$0G H H H

12G 0$G H H H

12G 1$0G H H H

9:; En&&$ Colle&e" :$:$Na&ar a&e I


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)able$5;0radeExperimentalro&ramme

rade of

Concrete

G of

Silica

Fume

=se

Gof

Cellulose

Fibre =se

No$ of

Cubes

for

Comp$

)est

No$ of

9eams

for

Flexural

)est

No$ of

Cylinders

for Split

)ensile

)est

)otal

Specimen

for A

days )est

)otal

Specimen

for 2I

days

)est

)otal

Specimen

for @

days

)est

)3>

AG 0$G H H H

AG 1$0G H H H

HG 0$G H H H

HG 1$0G H H H

12G 0$G H H H

12G 1$0G H H H

9:; En&&$ Colle&e" :$:$Na&ar a&e H


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CHAPTER 7

6OR= PLAN

7.1 6OR= PLAN

Fi& $1 Wor( lan

9:; En&&$ Colle&e" :$:$Na&ar a&e @0

TOPICSEARCH

SELECTION OFTOPIC&LITRATURE

COLLECTION

LITERATUREREVIEW

SCPOEOFWORK&OBJECTIVES

MATERIALORDER&DESIN MI!

STARTIN OFE!PERIMENTS

TESTINE!P"WO

COMPLE#TIONOFE!P"WORK

RESULTANAL$SIS ANDCOMPARISION

PRESEN#TATION

SUBMISSION&DISSERT

ATIONDEFENCE


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CHAPTER 8

REFERANCES

8.1 REFERANCES

P!(er'

416 /uchey and ,utta1HH@3 JConcrete reinforcement #ith recycled fibresK by

Qou+ian& Wan&"1 $ C$ Wu"2 and :ictor C$ Di in .


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4A6 Naamanet$el 1HH@3 JConcrete reinforcement #ith recycled fibresK by Qou+ian&

Wan&"1 $ C$ Wu"2 and :ictor C$ Di in .


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S$!"*!r*' IS Co*e'

/C% Report Committee 55" J;ethods of )est for %mpact Stren&th"K /C%"

/merica$

%ndian Standard ,esi&nation %S 1@-1HH" J;ethods of )est for Stren&th of

Concrete"K 9%S"Ne# ,elhi" 2002$

%S I* 1HA0" JSpecification for Coarse a&&re&ate and Fine a&&re&ate from

Natural Sources for ConcreteK" 9ureau of %ndian Standard" Ne# ,elhi

%S I1@* 1HHH" JSplittin& )ensile Stren&th of Concrete ;ethod of )estK" 9ureau

of %ndian Standard" Ne# ,elhi

experimental study on effect of silica fume with natural cellulose fibre in frc

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