proportion of mortar & concrete

8/10/2019 Proportion of Mortar & Concrete

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STRENGTH DEVELOPMENT OF CEMENT MORTAR AND

CONCRETE INCORPORATING GGBFS

Abstract

In the present study, the effect of curing procedure on the compressive strength development

of cement mortar and concrete incorporating ground granulated blast furnace slag is studied.

The compressive strength development of cement mortar incorporating 20, 40 and 60

percent replacement of GGB! for different types of sand and strength development of

concrete "ith 20, 40 and 60 percent replacement of GGB! on t"o grades of concrete is

investigated. The compressive strength of cement mortar and concrete obtained at the ages

of #, $, 2%, &6, '0, (&0 and (%0 days. Tests results sho" that the incorporating 20) and 40)GGB! is highly significant to increase the compressive strength of mortar after 2% days

and (&0 days respectively. The magnitude of compressive strength of mortar for standard

sand is higher than the magnitude of river sand. Incorporating 60) B! replacement is

sho"ing lo"er strength at all ages and "ater*cement ratio for both types of sand. The

compressive strength of +- concrete sho"s higher strength as compare to the GGB!

based concrete for all percent replacement and at all ages. Incorporating 40) GGB! is

highly significant to increase the compressive strength of concrete after &6 days than the 20

and 60) replacement. mong GGB! based concrete 40) replacement is found to be

optimum.

Keywords Blast furnace slag/ compressive strength/ cement mortar/ concrete/ curing/ time

!" I#trod$ct%o#

The reuse of industrial by products is gaining popularity since last fe" decades due to its

long*term performance characteristics. -oncrete is no"n for its compressive strength

"hich is an important property in the design and the construction of the concrete structures.

lthough, concrete is very strong in compression, but, due to the development of various

types of admi1tures, it is necessary to investigate the effect of mineral admi1tures on the

compressive strength of cement mortar and concrete. iterature sho"s that very little data is

available on the strength development of mortar and concrete containing ground granulatedblast furnace slag 3GGB! 5(*%. or this purpose, e1perimental investigation is carried out

to

develop the data on the compressive strength development of mortar and concrete "ith time

and "ith different percent replacement of GGB!. The ob7ectives of the present study are8

To select the GGB! mi1 proportion for cement mortar and +- concrete.

To investigate the effect of fine aggregates on compressive strength development of

cement mortar "ith GGB! replacement.

To perform the e1periments on the time*dependent compressive strength of cement

mortar and concrete containing GGB!. The strengths "ere measured at the age of #, $,

2%, &6, '0, (&0 and (%0 days.

&" E'(er%)e#ta* Pro+ra)

2.1 Materials properties

T"o strength of concrete is obtained on the basis of trial in the present study, i.e. 46.&0 9a

and #$.0' 9a concrete and designated as 9i1*I and 9i1*II. The test specimen "ere cast


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using cement, fine aggregate, coarse aggregate, "ater and GGB!. The materials, confirmed

to the specification laid do"n in the relevant Indian !tandard codes. The follo"ing section

describes the physical properties of the material used in the study.

Table (. hysical properties of ordinary portland cement 3+,-

C,aracter%st%cs E'(er%)e#ta* -a*$es

Blaine:s fineness 3m2;g #0(

!pecific gravity #.(&

!oundness 3mm #.&


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!T>?esidue 4% '.6 -


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64

Table 4. !ieve analysis and physical properties of coarse aggregate

IS S%e-e

des%+#at%o#

.e%+,t

reta%#ed /+)0Perce#t

we%+,t

reta%#ed

(erce#t

we%+,t

(ass%#+

C$)$*at%-e

(erce#t we%+,t

reta%#ed

%0 mm

40 mm

20 mm

(0 mm

4.$& micron

>esidue

hysical properties8

0

0

40

%(&0

(&&0

260

-

-

0.4

%(.&

(&.&

2.6

(00

(00

''.6

(%.(

2.6

-

-

-

0.4

%(.'

'$.4

-

ineness modulus F 6.%

!pecific gravity F 2.6#

Aensity 3loose F (4.#


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!T>?


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66

Ground granulated blast furnace slag concrete mi1es "ere prepared after re*

proportioning the +- concrete mi1es. The cement in +- concrete mi1es "as directreplaced by the eCual "eight of blast furnace slag "ith cement replacement of 20, 40 and

60percent respectively. The ratio of fine aggregate and coarse aggregate "as ept constant

for the entire investigation. The amount of fine aggregate and coarse aggregate "as ept

constant. The "ater for a particular mi1 "as also ept constant.The details of granulated

blast furnace slag are given in the Table $.

Table $. GGB! based concrete mi1 proportion

M%'

D%rect (erce#t

re(*ace)e#t o6

GGBFS /50

Ce)e#t

/2+3)10

GGBFS

/2+3)10

F%#e

a++re+ate

/2+3)10

Coarse

a++re+ate

/2+3)10

w3c

rat%o

20 #20 %0

9i1*I 40 240 (60 66& ((0$ 0.4&

60 (60 240

20 2%0 $0

9i1*II 40 2(0 (40 6%0 ((#2 0.&0

60 (40 2(0

3.3 Testing Procedre

or each mi1 #& samples of $0.6 1 $0.6 1 $0.6 mm cube for compressive strength "as

prepared. fter 24 hr the sample "as demoulded and cured for the period of #, $ and 2%

days. (& samples of cube "ere tested at the age of #, $ and 2% days curing. fter 2% days

curing, the remaining sample "as ept at room temperature 32$#0- until the time of

testing for &6, '0, (&0 and (%0 days results.

!imilarly,for concrete mi1es, compression tests "ere carried out in accordance "ith I!8

&(6*('&' 5(# at a loading rate of (4


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!T>?elationship bet"een compressive strength of cement mortar containing GGB! "ith

-o

m

res

si

e

!ten

gt

h

39

,a

-omp

ressiv

e!tr

ength39,a


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6%

time for river sand for "ater F cement consistency

60

lain 9ortar3$%ml

20) B! 3%(ml

&040) B! 3%#ml

60) B! 3%$ml

Sta#dard Sa#d

40

#0

20

(0

0

# $ 2% &6 '0 (&0 (%0

Time 3days

igure #. >elationship bet"een compressive strength of cement mortar containing GGB! "ith

time for standard sand for "ater F cement blending consistency

60

lain 9ortar

3$%ml

20) B! 3%(ml

&040) B! 3%#ml

60) B! 3%$ml

40

R%-er Sa#d

#0

20

(0

0

# $ 2% &6 '0 (&0 (%0

Time 3days

-omp

res

siv

e!tr

en

gt

h39

,a

-ompresive!tr

ength9


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!T>?


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$0

The magnitude of compressive strength of +- and B! replacement mortar is higher in

case of standard sand as compare to the river sand at all ages. The reason of higher strengthin standard sand is due the coarser particles in river sand and due to the non uniform grading

of river sand. 9ost of the failure occurs due to the early bond failure bet"een the paste and

coarser particle of the river sand.

!.2 Compressi"e strengt# de"elopment o$ concrete

The variation of cube and cylinder compressive strength of ordinary concrete and concrete

containing GGB! "ith time is sho"n in igure & to % for 9i1*I and 9i1*II. igure sho"s

that the compressive strength increases "ith the time at a decreasing rate. The pattern of

strength development is same in all the mi1.

t the age of 2% days the cube compressive strength of GGB! concrete mi1es "ith

cement replacement of 20, 40 and 60 percent "as observed to be %#, $& and 6& of the plainconcrete for 9i1*I respectively.or 9i1*II this percentage "as observed as %', %4 and $#

percent of the plain concrete. !imilarly, the cylinder compressive strength of GGB!

concrete mi1es "ith cement replacement of 20, 40 and 60 percent "as observed as %#, $$

and 66 percent for 9i1*I and %$, %( and $( percent for 9i1*II respectively.@o"ever, at the

age of (%0 days this variation of cube compressive strength development of GGB!

concrete "ith the cement replacement of 20, 40 and 60 percent is increased as '#, '$ and $4

percent for 9i1*I and '#, '$ and %0 percent for 9i1*II respectively "ith the lain concrete

strength.

60

&0

40

#0

20

9i1*I*lain -oncrete

9i1*I*20 )

B! 9i1*I*40

) B! 9i1*I*

60)B!

0

0 20 40 60 %0 (00 (20 (40 (60 (%0 200

Time 3days

igure &. -ube compressive strength development "ith time for plain and GGB! concrete for

9i1*I

-u

be

-o

mpres

siv

e

!tr

en

gth

39,a


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!T>?


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$2

40

#&

#0

2&

20

(&

(0 9i1*II*lain -oncrete

9i1*II-20) B!

& 9i1*II-40)B!

9i1*II-60) B!

0

0 20 40 60 %0 (00 (20 (40 (60 (%0 200

Time 3days

igure %. -ylinder compressive strength development "ith time for plain and GGB! concrete

for 9i1*II

ie"ise, for cylinder compressive strength the variation in strength development after

(%0 days "as observed as '&, '$ and $& percent for 9i1*I and '#, '$ and %0 percent for

9i1*II respectively "ith the concrete strength "ithout GGB!.

The increase in cube compressive strength of plain concrete from 2% to (%0 days is

observed (6 percent "hereas the increase in cube compressive strength of 20, 40 and 60

percent cement replacement "ith GGB! is observed #2, &0 and #2 percent respectively for

9i1*I. !imilarly, for 9i1*II the increase in compressive strength of plain concrete is

observed as 20 percent and compressive strength of 20, 40 and 60 percent replacement is 26,

#' and ## percent respectively for 9i1*II. The increase in cylinder compressive strength

from 2% to (%0 days is almost same for 9i1*I but lo"er for 9i1*II than the cube

compressive strength. or plain concrete mi1 it is observed (%, and (6 for 9i1*I and 9i1*II

respectively and for cement replacement of 20, 40 and 60 percent "ith GGB! #4, 4% and

#4 percent for 9i1*I, and for 9i1*II it is 24, #% and #0 percent . This type of strength

development of GGB! concrete is observed by 9alhotra 5('%$ for -anadian pelletiDed

slag concrete.

The strength of concrete at a given age and the rate of strength development are depends

upon the type and characteristics mi1 proportion of the slag in concrete. This sho"s that the

poDDolanic reactivity of GGB! contributes to the rate of gain of strength at later ages.

In all the t"o mi1es, plain concrete strength is found higher than the GGB! replacement

"ith cement. The reason for this is due the method of mi1 proportioning and curing

conditions. In the present study the curing period "as 2% days, after that the remaining

-lin

der

-om

res

si

e!tr

en

gt

h39


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!T>?egourd 5(4 and >oy and Idorn 5(&.The predominant reaction is due to thealali hydro1ide but, at later ages dominant reaction is due to the calcium hydro1ide. t

higher cement replacement the amount of cement for hydration and liberation of calcium

hydro1ide is smaller. The cement replacement of 40 percent "ith GGB! yields the

hydration products due to the poDDolanic reaction and fills the pores results in increase in

strength of concrete among GGB! based concrete. The concrete containing 60 percent

GGB! sho"s decrease strength at all ages. The decrease in strength is due the presence of

e1cessive fines "hich "ill cause greater mobility of the unhydrated GGB! particle. The

failure taes place due to the early crushing of paste and @ence strength is found lo"er than

the 20 and 40 percent replacement of GGB! at all ages.

:" Co#c*$s%o#s

Based on the above study the follo"ing conclusions are dra"n.

%.1 Cement mortar compressi"e strengt#

(. Test results sho" that the incorporating 20) and 40) GGB! is highly significant to

increase the compressive strength of mortar after 2% days and (&0 days respectively.

2. The magnitude of compressive strength of mortar for standard sand is higher than the

magnitude of river sand.

#. Incorporating 60) B! replacement is sho"ing lo"er strength at all ages and "ater*

cement ratio for both types of sand.

%.2 Concrete compressi"e strengt#

(. The compressive strength of +- concrete sho"s higher strength than the GGB!

based concrete for all replacement 3in percent and at all ages.

2. Incorporating 40) GGB! is highly significant to increase the compressive strength of

concrete after &6 days than the 20 and 60) replacement.

#. mong GGB! based concrete 40) replacement is found to be optimum.


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proportion of mortar & concrete

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