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A REPORT ON TECHNICAL SEMINAR

Submitted in partial fulfillment of the requirements for the award of

BACHELOR OF ENGINEER

In

CIVIL ENGINEERING

By

B. CHANDRA SEKHAR

BE 4/4 CIVIL-A2

1601-11-732-317

Under the uidan!e of

FACULTY OF CIVIL ENGINEERING DEPARTMENT

CBIT-HYDERABAD

DEPARTMENT OF CIVIL ENGINEERING

CHAITANYA BHARATHI INSTITUTE OF TECHNOLOGY

"#$%&'B'$- '($"&' )&'$%S"

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CHAITANYA BHARATHI INSTITUTE OF TECHNOLOGY

Gandi!"# H$d!%a&ad-'((()'

DEPARTMENT OF CIVIL ENGINEERING

' &eport on te!hni!al Seminar *ondu!ted by the $epartment of *i+il %nineerin,

*haitanya Bharathi Institute of e!hnoloy, "yderabad as a part of *urri!ulum for B.% //

2ndSemester. IB%& &%I(&*%$ *(*&%%4 is the title of the &eport )resented.

Submitted By

B. *handra Se5har 160111732317

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D E C L A R A T I O N

I hereby de!lare that the &eport of the Seminar entitled IB%& &%I(&*%$

*(*&%% whi!h is bein submitted to the *BI in partial fulfillment of the

requirements for the award of the Ba!helor of %nineer in the *i+il %nineerin is a

report of the wor5 !arried out by me. he material !ontained in this &eport has not been

submitted to any Uni+ersity or Institution for the award of any other !ertifi!ate or deree.

B. *handra Se5har.

$epartment of *i+il %nineerin

)la!e *BI-"#$%&'B'$

Da"!* 4-2-2(+'

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C E R T I F I C A T E

his is to !ertify that the &eport of the te!hni!al seminar entitled IB%& &%I(&*%$

*(*&%%4 submitted by B. *handra Se5har, bearin roll number 1601-11-732-317 as

the re!ord of the wor5 !arried out by him.

,,,,,,,,,,,,, ,,,,,,,,,,,,,..

Fa"$ in 0a%1! P%3.P.S%!!nia5 Sa%6a

T!0nia S!6ina% P%3!55% and H!ad

D!a%"6!n" 3 Cii En1in!!%in1 D!a%"6!n" 3 Cii En1in!!%in1

CBIT-HYD CBIT-HYD

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ACKNO7LEGDEMENT

It is our pri+ilee to than5 the )rin!ipal Sri B. *henna5esha+a &ao Sir and the "ead of the

$epartment, )rof. Sri ).Sreeni+as Sarma Sir.

8e would li5e to e9press ratitude to 'sst. )rof. Sri :.Sambasi+a rao Sir for uidin and

helpin us in this te!hni!al seminar.

I would li5e to than5 to my Ca556a"!5 for their support. ;ast but not least I would li5e to

than5 my Pa%!n"5for their !onstant support and inspiration in life. I am hihly indebted to

the almihty for all this blessins.

B. C0and%a S!80a%.

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FIBER REINFORCED

CONCRETE

I N T R O DUC T I O N

GENERAL*

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*on!rete is a !omposite material !ontainin hydrauli! !ement, water, !oarse

areate and fine areate. he resultin material is a stone li5e stru!ture

whi!h is formed by the !hemi!al rea!tion of the !ement and water. his stone

li5e material is a brittle material whi!h is stron in !ompression but +ery wea5

in tension. his wea5ness in the !on!rete ma5es it to !ra!5 under small loads, a t

the tensile end. hese !ra!5s radually propaate to the !ompression end of the

member and finally, the member brea5s. he formation of !ra!5s in the !on!rete

may also o!!ur due to the dryin shrin5ae. hese !ra!5s are basi!ally mi!ro

!ra!5s. hese !ra!5s in!rease in si


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'lso, it helps to maintain stru!tural interity and !ohesi+eness in the material.

he initial resear!hes !ombined with the lare +olume of follow up resear!h

ha+e led to the de+elopment of a wide +ariety of material formulations that fit

the definition of ibre &einfor!ed *on!rete.

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FIBRE REINFORCED CONCRETE*

iber reinfor!ed !on!rete =&*> is !on!rete !ontainin fibrous material whi!h

in!reases its stru!tural interity.So we !an define fibre reinfor!ed !on!rete as a

!omposite material of !ement !on!rete or mortar and dis!ontinuous dis!rete and

uniformly dispersed fibre.

ibre is dis!rete material ha+in some !hara!teristi! properties. he fibre

material !an be anythin. But not all will be effe!ti+e and e!onomi!al. Some

fibres that are most !ommonly used are7

? Steel

? @lass

? *arbon

? (atural

? (B$

Steel fibre is one of the most !ommonly used fibre. @enerally round fibres are

used. he diameter may +ary from 0.2A to 0.7Amm.he steel fibre sometimes

ets rusted and lose its strenth. But in+estiations ha+e pro+ed that fibres et

rusted only at surfa!es. It has hih modulus of elasti!ity. Use of steel fibres

ma5es sinifi!ant impro+ements in fle9ure, impa!t and fatiue strenth of

!on!rete. It has been used in +arious types of stru!tures.

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@lass fibre is a re!ently introdu!ed fibre in ma5in fibre !on!rete. It has +ery

hih tensile strenth of 1020 to /00:pa. @lass fibre !on!retes are mainly use in

e9terior buildin faCade panels and as ar!hite!tural pre!ast !on!rete. his

material is +ery ood in ma5in shapes on the front of any buildin and it is less

dense than steel.

Use of !arbon fibre is not a de+eloped pro!ess. But it has !onsiderable strenth

and younDs modulus. 'lso in+estiations ha+e shown that use of !arbon ma5es

the !on!rete +ery durable. he study on the !arbon fibres is limited. :a inly

used for !laddin purpose.

(atural fibres are low !ost and abundant. hey are nonha


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Source: ACI Committee 544, Report 544.IR-82, Concr. Int., Vo. 4, !o. 5,

p. 11, 1982

11

mparison of Mix Proportion between Plain Concrete and Fiber Reinforced Concrete

e 14-$%&' (e)ur% 'tren*t#, 8 +p%, o t#e er reinorce$ /%' %out 20 #i*#er t#%n t#%t o p%in concrete.

rce: A$%pte$ rom %nn%, A.!., CA Report R 049.01, ort%n$ cement A''oci%tion, Soie, I, 1977


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Gtop left steel fiber reinfor!ed !on!rete beams

Gtop riht lass fiber reinfor!ed !on!rete mi9

Gbottom left pre!ast steel fiber reinfor!ed tunnel walls

Gbottom riht !ounter top made with lass fiber reinfor!e !on!rete

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HISTORY*

he use of fibers to in!rease the stru!tural properties of !onstru!tion material is

not a new pro!ess. rom an!ient times fibres were bein used in !onstru!tion. In

B*, horse hair was used to reinfor!e mortar. %yptians used straw in mud

bri!5s to pro+ide additional strenth. 'sbestos was used in the !on!rete in the

early 1Hth

!entury, to prote!t it from formation of !ra!5s. But in the late 1Hth

!entury, due to in!reased stru!tural importan!e, introdu!tion of steel

reinfor!ement in !on!rete was made, by whi!h the !on!ept of fibre reinfor!ed

!on!rete was o+er loo5ed for A-6 de!ades. ;ater in 1H3H the introdu!tion steelrepla!in asbestos was made for the first time. But at that period it was not

su!!essful. rom 1H60, there was a tremendous de+elopment in the &*,

mainly by the introdu!tion of steel fibres. Sin!e then use of different types of

fibres in !on!rete was made. In 1H70Ds prin!iples were de+eloped on the

wor5in of the fibre reinfor!ed !on!rete. ;ater in 1H0Ds !ertified pro!ess was

de+eloped for the use of &*. In the last de!ades, !odes reardin the &* are

bein de+eloped.

PROPERTIES OF FIBRE REINFORCED CONCRETE*

)roperties of !on!rete is affe!ted by many fa!tors li5e properties of !ement, fine

areate, !oarse areate. ther than this, the fibre reinfor!ed !on!rete is

affe!ted by followin fa!tors7

?

ype of fiber

? 'spe!t ratio

? uantity of fiber

? rientation of fiber

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T$! 3 3i&%!*

' ood fibre is the one whi!h possess the followin qua lities7

? @ood adhesion within the matri9.

? adaptable elasti!ity modulus =sometimes hiher than that of the matri9>

? !ompatibility with the binder, whi!h should not be atta!5ed or destroyed

in the lon term

? an a!!essible pri!e, ta5in into a!!ount the proportion within the mi9

? bein suffi!iently short, fine and fle9ible to permit mi9in, transportin

and pla!in

? Bein suffi!iently stron, yet adequately robust to withstand the mi9in

pro!ess.

A5!" %a"i*

'spe!t ratio is defined as the ratio of lenth to width of the fibre. he +alue of

aspe!t ratio +aries from 30 to 1A0. @enerally the in!rease in aspe!t ratio

in!reases the strenth and touhness till the aspe!t ratio of 100. 'bo+e that thestrenth of !on!rete de!reases, in +iew of de!reased wor5ability and redu!ed

!ompa!tion. rom in+estiations it !an be found out that ood results are

obtained at an aspe!t ratio around 0 for steel fibres. Jeepin that in +iew we

ha+e !onsidered steel hoo5ed end fibres with aspe!t ratio of 0 =;enth 60 mm

and $iameter 0.7A mm>.

Fi&%! 9an"i"$*

@enerally quantity of fibres is measured as per!entae of !ement !ontent. 's

the +olume of fibres in!rease, there should be in!rease in strenth and touhness

of !on!rete. &eardin our fibre, we hope that there will be an in!rease in

strenth, with in!rease in fibre !ontent. 8e are oin to test for per!entaes of

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1.0, 2.0 and 3.0.

O%i!n"a"in 3 3i&%!*

he orientations of fibres play a 5ey role in determinin the !apa!ity of

!on!rete. In &** the reinfor!ements are pla!ed in desired dire!tion. But in

&*, the fibres will be oriented in random dire!tion. he &* will ha+e

ma9imum resistan!e when fibres are oriented parallel to the load app lied.

FIBRE MECHANISM*

ibre wor5 with !on!rete utili


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Fi&%! M!0ani56

FIBRE - MATRI: INTERACTION*

he tensile !ra!5in strain of !ement matri9 is mu!h lower than the yield or

ultimate strain of fibres. 's a result when a fibre reinfor!ed !omposite is

loaded the matri9 will !ra!5 lon before the fibres !an be fra!tured. n!e the

matri9 is !ra!5ed !omposite !ontinues to !arry in!reasin tensile stress. he

pea5 stress and strain of the !on!rete !omposite are reater than those of the

matri9 alone durin the inelasti! rane between first !ra!5in and the pea5.

:ultiple !ra!5in of matri9 o!!urs as indi!ated in fi.1.1.


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BRIDGING ACTION*

)ullout resistan!e of fibres =dowel a!tion> is important for effi!ien!y. )ullout

strenth of fibres sinifi!antly impro+es the post-!ra!5in tensile strenth of!on!rete. 's an &* beam or other stru!tural element is loaded, fibres bride

the !ra!5s. Su!h bridin a!tion pro+ides the &* spe!imen with reater

ultimate tensile strenth and, more importantly, larer touhness and better

enery absorption.

'n important benefit of this fibre beha+iour is material damae toleran!e.

Bayasi and Jaiser =2001> performed a study where damae toleran!e fa!tor is

defined as the ratio of fle9ural resistan!e at 2-mm ma9imum !ra!5 width to

ultimate fle9ural !apa!ity. 't 2K steel fibre +olume, damae toleran!e fa!tor

a!!ordin to Bayasi and Jaiser was determined as H3K.

P" M!0ani56.


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7ORKABILITY*

' short!omin of usin fibres in !on!rete is redu!tion in wor5ab ility.

8or5ability of &* is affe!ted by fibre aspe!t ratio and +olume fra!tion as well

the wor5ability of plain !on!rete.

's fibre !ontent in!reases, wor5ability de!reases. :ost resear!hers limit

+olume of fibres to /.0K and aspe!t ratio to 100 to a+oid unwor5able mi9es. In

addition, some resear!hers ha+e limited the fibre reinfor!ement inde9 L+o lume

of fibres as K Maspe!t ratioN to 1.A for the same reason. o o+er!ome thewor5ability problems asso!iated with &*, modifi!ation of !on!rete mi9 desin

is re!ommended. Su!h modifi!ations !an in!lude the use of additi+es.


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STEEL FIBRE REINFORCED CONCRETE

'!!ordin to %9odus %yptians used straw to reinfor!e mud bri!5s. here is

e+iden!e that asbestos fibre was used to reinfor!e !lay posts about A000 years

ao. )rof.'lberto a+a of the Uni+ersity of ;a )lata in 'rentina points out that

the hornero is a tiny bird nati+e to 'rentina, *hile, Boli+ia and other South

'meri!an !ountriesO the bird had been painsta5inly buildin straw reinfor!ed

!lay nests on tree tops sin!e the ad+ent of man. "owe+er, (.P.Be5aert is been

rearded as the father of Qibre &einfor!ed *on!reteQ.

+.).+ COMPOSITION OF STEEL FIBRE REINFORCED CONCRETE

he !omponents of Steel ibre &einfor!ed *on!rete =S&*> !an be e9plained

with the help of the iure i+en below.


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C6n!n"5 3 S"!! Fi&%! R!in3%!d Cn%!"!

*on!rete !ontainin hydrauli! !ement, water, fine areate, !oarse areate

and dis!ontinuous dis!rete Steel fibres is !alled Steel ibre &einfor!ed

*on!rete. It may also !ontain po


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Di33!%!n" 50a!5 3 S"!! Fi&%!5

he Steel ibres that we are usin in this proEe!t wor5 are "oo5ed ibres that

are lued to ea!h other and named R$rami9, manufa!tured by Be5aert ;imited,

Belium. It is shown in iure below.

$rami9 ibres used in the )roEe!t


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BEHAVIOUR OF STEEL FIBRE REINFORCED CONCRETE

UNDER CONVENTIONAL LOADINGS


UNDER DIRECT COMPRESSION

:a9imum stress a material !an sustain under !rush loadin is 5nown as

*ompressi+e strenth. he !ompressi+e strenth of a material that fails by

shatterin fra!ture !an be defined within fairly narrow limits as an independent

property. "owe+er, the !ompressi+e strenth of materials that do not shatter in

!ompression must be defined as the amount of stress required to distort the

material an arbitrary amount. *ompressi+e strenth is !al!ulated by di+idin thema9imum load by the oriinal !ross-se!tional area of a spe!imen !ompression

test.

FOR PLAIN CONCRETE

he stress strain !ur+e of !on!rete under unia9ial !ompression shows a linear

beha+iour up to about 30K of the ultimate strenth =fu> be!ause under short

term loadin the mi!ro !ra!5s in the transition


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&elation between !on!rete performan!e and e9tent of !ra!5in

rom the shape of the stress strain !ur+e it seems that, for a stress between 30 to

A0K of fu the mi!ro!ra!5s in the transition


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Based on the des!ribed !ra!5in staes, the beha+iour of !on!rete !an be

+iewed at two le+els irst, randomly distributed mi!ro!ra!5s are formed or

enlared under low le+el of stresses. 8hen tile stress le+el rea!hes a spe!ifi!

+alue, these mi!ro!ra!5s bein to lo!ali


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FOR STEEL FIBRE REINFORCED CONCRETE

*ompressi+e strenth is little influen!ed by steel fibre addition. "ih

!ompressi+e this !an be a!hie+ed usin sili!a fume or fly ash. "owe+er, the use

of steel fibres the mode of failure of hih strenth !on!rete from an e9plosi+e

brittle one to a more du!tile one, aain showin the in!reased touhness of

S&* and its ability to absorb enery under dynami! loadin.

* o m p r e s si+ e S tre n th o f S & *

he fibre type, +olume fra!tion and aspe!t ratio play important roles in

determinin the !ompressi+e du!tility and enery absorption !apa!ity of fibre

reinfor!ed !on!rete. he material beha+iour is enerally enhan!ed as the

+olume fra!tion and aspe!t ratio of fibres in!rease up to limits after whi!h the


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problems with fresh mi9 wor5ability and fibre dispersability start to damae the

hardened material properties. 's the in!reases in both fibre +olume fra!tion Pr

and aspe!t ratio 1d lead to impro+ement of the same nature in the !ompressi+e

beha+iour of the material, their !ombined effe!t has been enerally analy


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7A and 100 were in+estiated. It was reported that the addition of hoo5ed-end

steelfibres to !on!rete in!reased marinally the !ompressi+e strenth and the

strain !orrespondin to pea5 stress.


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UNDER FLE:URE

In numerous in+estiations, it has been displayed that the fle9ure, shear, torsion,pun!hin, dynami! impa!t beha+iours of stru!tural elements impro+ed by the

use of Steel ibre &einfor!ed *on!rete. he positi+e effe!ts of S&* on the

fle9ure beha+iour of the stru!tural elements are i+en as follows by *rai

=1H/>.

? In!reases moment !apa!ity and !ra!5in moment,

? In!rease the du!tility,

? In!reases !ra!5 !ontrol,

? In!reases riidity,

? )reser+es the stru!tural interity after beam e9!eeds the ultimate load.

FACTORS AFFECTING THE FLE:URE BEHAVIOUR OF STEEL

FIBRE REINFORCED COCNCRETE.

=a> I(;U%(*% S%%; IB&% P;U:% &'*I(

he influen!e of fibre +olume fra!tion is shown in iure. or H0 and 120

50m3 fibre !ontent, the post-!ra!5 in!rease in load is sinifi!ant. his in!rease

essentially pro+ides the impro+ement in fle9ural strenth and a stable post-!ra!5

beha+iour. 's shown, the bendin !apa!ity in!reases as the fibre +olume

fra!tion in!reases.


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Influen!e of fibre !ontent on the ;oad $efle!tion *ur+es and Influen!e of fibre

lenth on the ;oad $efle!tion *ur+es

=b> I(;U%(*% $ IB&% ;%(@"

he influen!e of fibre lenth is +ery sinifi!ant for straiht fibres. "owe+er, it is

an established fa!t that, loner fibres with hiher aspe!t ratios pro+ide better

performan!e in both strenth in!rease and enery absorption as lon as they !an

be mi9ed, pla!ed, !ompa!ted and finished properly. Sin!e hoo5ed-end fibres

pro+ide ood an!horae, an in!rease in aspe!t ratio of hoo5ed-end fibres has

less influen!e !ompared with straiht steel fibres. "owe+er, the differen!e

between fibre lenths be!omes e+en less sinifi!ant at hiher +olume fra!tions.


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=!> I(;U%(*% IB&% @%:%

hree different fibre eometry, namely hoo5ed-end fibres, !orruated

fibres and deformed-end fibres with equal lenth are studied on the

fle9ural beha+iour of Steel ibre &einfor!ed *on!rete by

@opalaratnam et al. =1HH1>. '!!ordin to testresults, !on!rete with

hoo5ed-end fibres ha+e hiher tensile strenth and post-!ra!5response than the other two types. he drop after the first pea5 is

mu!h more pronoun!ed for !orruated and deformed-end fibres.


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*omparison of effe!ts of steel fibre shapes on load-defle!tion

!ur+es. here are a number of fa!tors that influen!e the beha+iour

and strenth of


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S&* in fle9ure. hey are fibre orientation and fibre shape, fibre bond

!hara!teristi!s =fibre deformation>. 'lso, fa!tors that influen!e the

wor5ability of S&* su!h as water !ement ratio, density, air !ontent and

the li5e !ould also influen!e its strenth. he ultimate strenth in fle9ure

!ould +ary !onsiderably

dependin upon the +olume fra!tion of fibres, lenth and bond

!hara!teristi!s of the fibres and the ultimate strenth of the fibres.

$ependin upon the !ontribution of these influen!in fa!tors, the ultimate

strenth of S&* !ould be either smaller or larer than its first !ra!5in

strenth.

FLE:URAL BEHAVIOUR OF STEEL FIBRE REINFORCED

CONCRETE

@enerally, there are three staes of the load-defle!tion response of S&*

spe!imens tested in fle9ure. he three staes are7

1. ' more or less linear response up to point '. he strenthenin

me!hanism in this portion of the beha+iour in+ol+es a transfer of s tress

from the matri9 to the fibres by interfa!ial shear. he imposed stress is

shared between the matri9 and fibres until the matri9 !ra!5s at what is

termed as Qfirst !ra!5in strenthQ or Qproportional limitQ.

2. ' transition nonlinear portion between point ' and the ma9imum load

!apa!ity at point B =assumin the load at B is larer than the load at '>.

In this portion, and after !ra!5in, the stress in the matri9 is proressi+ely

transferred to the fibres. 8ith in!reasin load, the fibres tend to radually

pull out from the matri9 leadin to a nonlinear load-defle!tion response

until the ultimate fle9ural load !apa!ity at point B is rea!hed. his point


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is termed as Qpea5Q strenth.

3. ' post pea5 des!endin portion followin the pea5 strenth until

!omplete failure of the !omposite. he load-defle!tion response in this

portion of beha+iour and the deree at whi!h loss in strenth is

en!ountered with in!reasin deformation is an important indi!ation of the

ability of the fibre !omposite to absorb lare amounts of enery before

failure and is a !hara!teristi! that distinuishes fibre-reinfor!ed !on!rete

from plain !on!rete. his !hara!teristi! is referred to as touhness.


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; oa d $ ef le ! tio n * ur+ e o f S te e l ib r e & einf o r ! e d * on !ret e S pe !im e n s

he nonlinear portion between ' and B e9ists, only if a suffi!ient +o lume

fra!tion of fibres is present. or low +olume fra!tion of fibres =Pf T 0.AK>, the

ultimate fle9ural strenth !oin!ides with the first !ra!5in strenth and the load-

defle!tion !ur+e des!ends immediately after the !ra!5in load,


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ypi ! al ; o a d $ e f l e ! t io n * u r + e s o f S& * Beam s wit h lo w + o lu m e f ra ! t io n

o f f ib r e s


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wo !on!epts are proposed in the literature for e9plainin the fa!tors that affe! t

the manitude of the Qfirst !ra!5in strenth or proportional limitQ. ne !on!ept

relates the Qfirst !ra!5in strenthQ to the spa!in of the fibres in the !omposite

L&omualdi and Batson 1H63O &omualdi and :andel 1H6/N. he other !on!ept is

based on the me!hani!s of the !omposite materials and relates the Qproportional

limitQ to the +olume fra!tion of the fibre, aspe!t ratio and fibre orientation.

In the ibre spa!in !on!ept, it is stipulated that the +olume fra!tion of fibres

and fibre aspe!t ratio must be su!h that there is a fibre o+erlapO howe+er, e9!ept

for this, the fibre aspe!t ratio ;df whi!h has a sinifi!ant effe!t on the fle9ural

strenth of S&* is not a parameter in the fibre spa!in approa!h. %9perimental

results by some in+estiators L%dinton et al. =1H7/>O Swamy and :anat

=1H7/>N tend to show that the fibre spa!in !on!ept does not a!!urately predi!t

the first !ra!5in strenth of fibre-reinfor!ed !on!rete.

he law of !omposite materials is belie+ed to be simple and is pro+en

e9perimentally Lshah and &anan 1H71N to be more a!!urate for the predi!tion

of first !ra!5in strenth !omparison with the fibre spa!in !on!ept. he

!omposite materials approa!h is based on the assumptions in that the fibres are

alined in the dire!tion of the load, the fibres are bonded to the matri9, and the

)oissons ratio of the matri9 is


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3

Smmar! Fiber reinforced concrete is one of the oldest methods for reinforcing concrete

The main purpose of fiber reinforcement is to increases its structural integrity and improve

flexural behavior There are many different types of fiber that can be used for concrete reinforcement.

Is an economical way to reinforced concrete compared to regular steel.

References

+%mou, +ic#%e, %n$ o#n %nie/'i. Materials for Civil and Construction Engineers. Secon$ $ition. !..: e%r'on %, 2006. 576. rint

+e#t%, .., %n$ ..+ +onteiro. ;ier' in Concrete.


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