Elongation Index

TITLE: SCOPE:

ELONGATION INDEX OF COARSE AGGREGATE TO DETERMINE THE ELONGATION INDEX OF COARSE AGGREGATE.

APPARATUS: 

Sample divider, size appropriae o !e ma"im#m pari$le size o %e !a&dled or aler&aivel' a (la s!ovel a&d $lea&, (la, !ard !orizo&al s#r(a$e.



A )ala&$e.



Tes sieves, sizes a&d aper#res appropriae o !e spe$i(i$aio& o( !e maerial %ei&* esed. +ari$#lars o( es sieves, &omi&al aper#re sizes are -, /. 01, 0-, 23, 2-, 4.mm.



Tra's.



Meal le&*! *a#*e.

PROCEDURE:

Mi&im#m mass o( es porio&  Nomi&al size o(

Mi&im#m mass o( es porio& a(er re5e$io& o( oversize

maerial mm 301 023 2-

a&d #&dersize pari$les, 6* 2  0 2 - .

7Sieve a&al'sis 8as $arried o# i& a$$orda&$e 8i! sa&dard sieve. All !e a**re*ae reai&ed o& !e -mm es sieve a&d all all !e a**re*ae passi&* !e 4.mm es sieve. sieve. 7Ea$! o( !e i&divid#al size (ra$io&s reai&ed o& !e es sieves 8ere 8ei*!ed o!er !a& -mm sieves a&d sored !em i& separae ra's 8i! !eir size mar6ed o& !e ra's. 7T!e s#ms o( !e masses o( !e (ra$io&s i& !e ra's 8ere meas#red. T!e i&divid#al per$e&a*es reai&ed o& ea$! o( !e vario#s es sieves 8ere $al$#laed. A&' (ra$io& 8!ose mass is 9 or less o( mass 8ere dis$arded. T!e mass remai&i&* 8as re$orded. 7T!e le&*! *a#*e appropriae 8as sele$ed o !e size (ra$io& #&der es a&d ea$! pari$le 8as *a#*ed separael' %' !a&d. Elo&*aed pari$les 8ere !ose 8!ose *reaes dime&sio& preve&s !em (rom passi&* !ro#*! !e *a#*e a&d !ese 8ere pla$ed o o&e side. 7All !ese elo&*aed pari$les 8ere $om%i&ed a&d 8ei*!ed. CALCULATION:

Elo&*aio& I&de"

: ;M2
>!ere, M2

: !e s#m o( !e masses o( (ra$io&s !a !ave a mass *reaer !a& 9 o( !e oal mass

M0

: !e mass o( all !e elo&*aed pari$les

Co&sider sieve (ra$io& 01mm passi&* a&d 0-mm reai&ed i& o%servaio& s!ee, Toal mass

: 1?2 *

>ei*! o( (ra$io&

: 0-?3 *

+er$e&a*e o( reai&ed o( oal mass

: 0-?3< 1?2 X 2-: 09

>ei*! o( s#% divided (ra$io&

: 2---*

>ei*! reai&ed o& le&*! *a#*e ;deermi&ed=

: 2- *

>ei*! reai&ed o& le&*! *a#*e ;ad5#sed=

: 2-< 2--- " 0-?3 : 02 *

Toal >ei*! reai&ed o& le&*! *a#*e ;ad5#sed=

: 23? *

Elo&*aio& I&de"

: 23?< 1?2 "2-: 219

DISCUSSION:

T!e pari$le s!ape o( a**re*ae mass is deermi&ed %' !e per$e&a*e o( (la6' a&d elo&*aed  pari$les $o&ai&ed i& i a&d %' is a&*#lari'. T!e elo&*aio& i&de" o( a& a**re*ae is !e per$e&a*e %' 8ei*! o( pari$les 8!ose *reaes dime&sio& ;le&*!= is *reaer !a& o&e a&d (o#r (i(! imes ;2.1 imes= !eir mea& dime&sio&. T!e elo&*aio& es is &o appli$a%le o size smaller !a& 4.mm. T!e a**re*ae (rom ea$! o( !e size ra&*e is i&divid#all' passed !ro#*! !e appropriae *a#*e o( !e le&*! *a#*e 8i! !e lo&*es side i& order o separae !e elo&*aed pari$les. T!e elo&*aio& i&de" o( a& a**re*ae sample is deermi&ed %' separai&* !e elo&*aed pari$les a&d e"pressi&* !eir mass as a per$e&a*e o( !e mass o( !e sample es. T!is es is $o&d#$ed o& $oarse a**re*ae o assess !e s!ape o( a**re*aes. A**re*ae 8!i$! are elo&*aed or (la6' are derime&al o !e !i*!er 8or6a%ili' a&d sa%ili' o( mi"es. I is &o $o&d#$ive o *ood i&erlo$6i&* a&d !e&$e !e mi"es 8i! a& e"$ess o( s#$! pari$les are di((i$#l o $ompa$ o re@#ired de*ree. T!e paveme& $o&sr#$io& elo&*aed pari$les o %e avoided, pari$#larl' i& s#r(a$e $o#rse. I( !e elo&*aed a**re*aes are prese& i& appre$ia%le proporio&s, !e sre&*! o( !e paveme& la'er  8o#ld %e adversel' a((e$ed d#e o possi%ili' o( %rea6i&* do8& #&der load. I& $eme& $o&$ree !e 8or6a%ili' is also red#$ed. Ho8ever, red#$io& i& sre&*! i& $eme& $o&$ree depe&ds o& !e $eme& $o&e& a&d 8aer7$eme& raio. Elo&*aed a&d (la6' a**re*aes are less 8or6a%le, !e' are also li6el' o %rea6 #&der smaller loads !a& !e a**re*ae 8!i$! are sp!eri$al or $#%i$al. REFERENCE:

2. Ceme& a&d $o&$ree s$ie&$e a&d e$!&olo*', ol#me B 2, par B 2, )' Dr. S.N. G!os!.