concrete lab. manuals

8/13/2019 Concrete Lab. Manuals

1/28

TEST ON CEMENT

Object: To determine % water content for cement paste of Normal Consistency.

Apparatus: Vicats apparatus with plunger (300 gm) !alance (" #g) Trowel $top

atch & Vicats mould.

Theory: Cement 'aste of Normal Consistency is defined y % water y weight of cement

which produces a consistency which penetrates a plunger of "0mm dia to penetrate upto

a depth mm to *mm a o+e the ottom of the Vicats mould.

Procedure:". eigh 300 gms of cement and place it in the enamel tray.

,. To start with add a out ,-% of water of mi it y means of a spatula. Care

should e ta#en that the time of gauging is not less than 3minutes and not more

than minutes. The gauging time shall e counted from the time of adding water

to the dry cement until commencing to fill the mould.

3. /ill the Vicats mould with this paste the mould resting on non porous plate.

1. 2a#e the surface of the cement paste in le+el with the top of the mould with a

trowel.

. 'lace this mould together with the non porous plate under the oil earing the

plunger. d4ust the indicator to show 0 0 when it touch the surface to the test

loc#.

5. 6elease the plunger 7uic#ly allowing it to sin# into the paste.

*. 'repare trail paste with +arying % of water and test as descri ed a o+e until

needle penetrates *mm a o+e the ottom of the mould.

-. 8 press this amount of water as a % y weight of the dry cement.

Precautions:a. Clean appliances should e used for gauging.

. The temperature of cement and water and that of room at the time of test should

e , 9C : ,9C.

c. ;n filling the mould the operators hand and the lade of the gauging trowel alone

e used.

"


2/28

Observation Table:(i) 6oom temperature.

(ii)

$l. No.

Test ater=Cement 6atio

" $etting Time 0.- ', $oundness y ?e Chatelier 2ethod

$oundness y uto Cla+e 2ethod0.*-''

3 Compressi+e strength on ">3 cement & standardsand mortar e pressed as % of dry weight ofcement & sand.

'[email protected]

Questions:". Aow do you define consistency of standard cement pasteB

,. hy it is necessary to conduct the test for determining consistency of standard

cement pasteB

,


3/28

DETERMINATION OF INITIAL AND FINAL SETTING TIME FOR CEMENT

Object: To determine the ;nitial and /inal $etting Time for cement.

Apparatus: Vicats apparatus with needle and mould !alance (" #g) Trowel $top

atch Trough $patula and Thermometer.

Theory: hen water is mi ed with cement to form a paste reaction starts out of three

main compounds +i . C 3 C3$ and C , $ the C3 reacts 7uic#ly with water to produce

4elly li#e compound which starts solidifying.

During the ne t stage of hydration cement paste starts hardening due to reaction of C 3$

and C , $ and the paste gains strength.

Thus initial and final setting times are defined as ar itrarily +i .>

Initial Setting Time is defined as the period elapsing etween the time when the water is

added to the cement and the time at which needle of "mm s7uare section falls to pierce

the test loc# to a depth of a out mm from the ottom of the mould.

inal Setting Time is defined as the period elapsing etween the time when the water is

added to the cement and the time at which the needle of "mm diameter cross section with

mm dia attachment ma#es an impression on the test loc# while the attachment falls to

ma#e an impression on the test loc#.

/or Erdinary 'ortland Cement s per !;$

;nitial $etting Time 2inimum F 302inutes/inal $etting Time 2a imum 500 2inutes

Procedure:

!a" Initial Setting Time:". Ta#e 300 gm of cement and use water as per 0.- ' and prepare cement paste.

,. $tart $top atch at the instant when water is added to the cement.

3. /ill the Vicats mould. The gauging time should e etween 3 minutes.

1. ?e+el the top surface and place the test loc# confined in mould and resting on

the non porous plate under the rod.

. ?ower the rod after , minutes and note penetration

5. 6epeat this procedure till needle fails to pierce the test loc# for a out mm. This

time since the water added will e initial setting time.

3


4/28

!b" inal Setting Time

". ;n this test replace the proper needle.

,. En releasing the needle impression will e li#e circle

3. 6epeat the a o+e procedure till getting the impression of needle only.

1. Note the time and this will represent final setting time since water is added to

cement.

Precautions:". Needle should e cleaned e+ery time.

,. $hift the position of the mould after recording the penetration reading.

3. Clean appliances should e used for gauging.

1. The temperature of room at the time of test should e ,*9C : ,9C.

. ;n filling the mould the operators hand and the lade of the gauging trowel alone

e used.

Observation Table:(i) 6oom temperature.

(ii)


5/28

Discussion: This e periment is intended to find out for a gi+en cement the 7uantity of

water (') to e mi ed to gi+e a paste of standard consistency. The +alue of w=c (') is

useful in following e periments ecause w=c ratio for those e periments is standard.

ater cement ratio for cement paste (') of normal consistency as>

$l. No.

Test ater=Cement 6atio

" $etting Time 0.- ', $oundness ?e Chatelier 2ethod

$oundness uto Cla+e 2ethod0.*-''

3 Compressi+e strength on ">3 cement & standardsand mortar e pressed as % of dry weight ofcement & sand.

'[email protected]

Questions:a. Aow do you define consistency of standard cement pasteB

. hy it is necessary to conduct the test for determining consistency of

standard cement pasteB


6/28

DETERMINATION OF SOUNDNESS TEST ON A GIVEN SAMPLE OFCEMENT BY LE-CHATELIER MOULD

Object: To determine soundness test on a gi+en sample of cement.

Apparatus: ?e Chatelier apparatus , Glass $heets trowel 2easuring Cylinder Aeater

8namel Tray Thermometer $top atch and !alance (" #g)Theory: ;t is essential that cement concrete does not undergo large change in +olume

after it has hardened. The +olume change occurs mainly due to free lime and to some

e tent due to presence of magnesia. Thus cement is said to e unsound when the

e pansion of specimen y ?e Chatelier method is more than "0%. .

Procedure:". 'lace the mould on a glass sheet and fill it with cement paste formed y gauging

cement with 0.*-'. Care should e e ercised to #eep the edges of the mouldgently together while this operation is eing performed.

,. Co+er the mould with another piece of glass sheet.

3. 'lace the small weight on this co+ering glass sheet and after H hour su merge the

whole assem ly in water at the temperature of ,*9C to 3,9C and #eep there for ,1

hours.

1. 2easure the distance separating the indicating point to an accuracy of a mm.

. $u merge the mould again in water at a temperature prescri ed a o+e.

5. !ring the water to oiling with the mould #ept su merged and #eep it oiling for

at least H hours.

*. 6emo+e the mould from the water allow it cool and measure distance etween

the indicator points.

-. The difference etween these two measurements represents the e pansion of the

cement.

5


7/28

Precautions I". ll the measurements of 7uantity of cement and the water should e done

accurately y weight.,. The edge of the split mould should e #ept together gently while filling the

mould with the paste. 8+en a fine thread can e wound +ery gently so as to a+oidthe splitting up of the rass mould due to filling of the paste.

3. ater should e rought to oiling point gradually in the specified time.1. ?e Chatelier apparatus should e handled y pressing indicator arms.

Observation Table:

$l.

No.

Description !efore

eration

fter

eration" eight of cement sample (g), ater re7uired for standard consistency (p)3 ater added to the sample (0.*-%)1 Time at which the sample is put in water at ,*9C

Time when the water is rought to the oiling point5 Distance etween pointer ends efore heating (D ")* Time for heating- Distance etween pointer ends after heating (D , )J Difference (D , D")

Result: Discuss:

hich compounds cause soundness in concreteBhat is effect if unsound cement is used in structuresB

6ef> (") ;$ ,5J (,) $' ,3 (3) Concrete Technology y VN Va irani and $.'. Chandola."5)

3 0

0.)mm

$'?;T$

;ND;C3TE6$

?e Chatelier 2ould

G?3$$ '?3T8$

3

3

*


8/28

DETERMINATION OF COMPRESSIVE STRENGTH OF CEMENT

Object: To determine the compressi+e strength of cement.

Apparatus: *0mm si e Cast ;ron Cu e 2oulds 'an 2i er Vi rating Ta le !alance

Trowel $top atch Trough $patula and Thermometer.

Theory: The compressi+e strength test is final chec# on the 7uality of cement. hen

water is mi ed in ">3 cement & standard sand mortar The fine aggregate used is thestandard sand specified y ;$ 5 0.The compression test ena les also to distinguish rapid

hardening cement from low heat and ordinary cement. The E'C is now eing classified

as 33 grade 13 grade and 3 grade E'C depending on the strength of cement.

Compressi+e strength measured as 3 * ,- days.

Procedure:a) The material for each cu e shall e mi ed separately and 7uantities of cement

standard sand and water are as follows>Cement ,00gmsK standard sand 500gms

ater '=1@3% of com ined wt. of cement and sand.

) 'lace on non porous plate a mi er of cement and standard sand in the proportion

of ">3 y wt. as gi+en a o+e.

c) 2i it dry with a trowel for one minute and then add water until the mi is of

uniform colour.

d) Gauging time should not e less than 3 minutes and should not e ceed 1 minutes.

;f it e ceeds mi ture is re4ected and operation is repeated.

e) Eil the interior face of the mould.

f) 'lace the assem led mould on the ta le of +i ration machine and firmly hold it in

position y means of suita le clamps.

g) ;mmediately after mi ing the mortar as specified a o+e place the entire 7uantity

of the mortar in the hopper a o+e the cu e mould and compact the same y

+i ration for a period of a out , minutes at a speed of ",00@100 +i ration per

min.

h) Leep the cu e at a temperature of ,* 0c@,0c in an atmosphere of at least J0%

relati+e humidity for ,1 hrs after completion of +i ration.

-


9/28


10/28

FINENESS MODULUS OF SAND AND BULKING OF SAND

Object: To Determine (i) The /ineness 2odulus of sand and (ii) !ul#ing of sand.

Apparatus: $et of ;$ $ie+es !alance Cylindrical Container Graduated Cylinder $teel

6ule $ie+e $ha#er.Theory: $and as a fine aggregate is used in mortars coarse aggregate is the ro#en stone

used in concrete where as the mi ed aggregate is limited to ma imum of 1.* mm eyond

which it is #nown as coarse aggregate. ineness $odulus is only a numerical inde of

fineness gi+ing some idea of the mean si e of particle in the entire ody of aggregates.

Determination of the fineness modulus may e considered as a method of standardi ation

y sie+ing a #nown weight of gi+en aggregate in a set of standard sie+es and y adding

the % weight of material retained on all the sie+es y di+iding the total % y "00.

The o 4ect of fineness modulus is to grade the gi+en aggregate for the most economical

mi and wor#a ility with 7uantity of cement.

%ul&ing o# Sand I The difficulty with measurement of fine aggregates y +olume is the

tendency of sand to +ary in ul# according to moisture contents. The e tent of this

+ariation is gi+en y this test. The ul#ing of sand occurs due to surface tension due to

this particles are pulled apart. ;f sand is measured y +olume ul#ing should e properly

accounted for.

Procedure:(a) Fineness Modulus of Fine Aggregate

(i) Ta#e "#g of sand from a la oratory sample of "0#g.

(ii) rrange the sie+e in the order such that "0mm sie+e is at the top and " 0

micron at the ottom. /i the ottom and co+er at the top.

(iii) Leep the sand in the top sie+e and carryout the sie+ing in set of sie+es for "0

minutes.

(i+) /ind weight retained on each sie+e.

"0


11/28


12/28

%ul&ing o# Sand

eight of Dry $and

Aeight of loose dry sand P (h)

$l. No.

t. of wateradded

% of wateradded

Aeight ofsand incylinder(h)

% !ul#ingPh "00 = h

6emar#s

Results:

". Draw a graph etween % water content & % ul#ing

,. 2a . ul#ing occurs at water content

3. /ineness modulus of /. . is P

Discussion:

". hat happens to concrete if allowance for ul#age for moist sand is not made

during +olume atchingB Aow will it affect mi proportionsB

,. ;s ul#age allowance necessary if weight atching is resortedB

3. Aow is ul#ing of sand e pressedB

Re#erences:". $' ,3.,. Concrete Technology y Vi irani and $.'. Chandola.3. Concrete Technology y .2. Ne+ille.

",


13/28

FINENESS MODULUS OF COARSE AGGREGATE

Object: To Determine the /ineness 2odulus of coarse aggregate.

Apparatus: $et of ;$ $ie+es !alance Cylindrical Container Graduated Cylinder $teel

6ule $ie+e $ha#er.

Theory: $and as a fine aggregate is used in mortars coarse aggregate is the ro#en stone

used in concrete where as the mi ed aggregate is limited to ma imum of 1.* mm eyond

which it is #nown as coarse aggregate. ineness $odulus is only a numerical inde of

fineness gi+ing some idea of the mean si e of particle in the entire ody of aggregates.

Determination of the fineness modulus may e considered as a method of standardi ation

y sie+ing a #nown weight of gi+en aggregate in a set of standard sie+es and y adding

the % weight of material retained on all the sie+es y di+iding the total % y "00.

The o 4ect of fineness modulus is to grade the gi+en aggregate for the most economical

mi and wor#a ility with 7uantity of cement.

Procedure: Fineness Modulus of Coarse Aggregate

;n this case sie+es of si e -0mm to ,.35mm are used.

". Ta#e ,#g of coarse aggregate from a la oratory sample of "0#g.

,. rrange the sie+e in the order such that -0mm sie+e is at the top and ,.35mm at

the ottom. /i the ottom and co+er at the top.

3. Leep the sand in the top sie+e and carryout the sie+ing in set of sie+es for "0

minutes.

1. /ind weight retained on each sie+e.

'36T;C3? $; 8

% / ; N 8 6

G63'A /E6 TA8 8O'. E/

/;N8N8$$ E/ 2EDM?M$

"3


14/28


15/28

SPECIFIC GRAVITY OF COARSE AGGREGATE

Object: Determine specific gra+ity of coarse aggregate y pycnometer.

Apparatus: !alance E+en 'ycnometer ir dried tray n air tight container /ilter paper and funnel.

Theory: specific gra+ity is the ratio of the weight of aggregate maintained for ,1 @ "=,

hours at temperature "00 0C to ""0 0C to the weight of e7ual +olume of water displaced y

saturated surface dry aggregate.

pparent specific gra+ity is the ratio of the weight of aggregate dried maintained for ,1 @

"=, hours at temperature "00 0C to ""0 0C to the weight of e7ual +olume of water displaced

y dry aggregate.

Procedure:". sample a out "#g for "0mm to 1.* mm or 00gm if finer then 1.* mm is

placed in the tray and co+ered with distilled water at temp. of ,, 0C to 3,. 0C.

,. $oon after immersion air entrapped in or u les on the surface of the aggregate

are remo+ed y gentle agitation with rod. The sample shall remain immersed for

,1 @ "=,.

3. The water is carefully drained off from the sample y decantation through a filter

paper. .

1. The aggregate including any solid matter retained on the filter paper is e posed

to a gentel current of warm air to e+aporate surface moisture and is stirred at

fre7uent inter+als to ensure uniform drying until no free surface moisture can e

seen.

. The saturated and surface dry sample is weighed ( eighed ).

5. The aggregate is then placed in pycnometer and then it should e filled with

distilled water.

*. ny air entrapped is eliminated y rotating the pycnometer on it side the hole ofape of the cone co+ered with finger.

-. The pycnometer is then dried on the outside and weighed (!). The contents of the

pycnometer are then transferred into a tray care eing ta#en to ensure that all the

aggregate is transferred.

"


16/28

J. The pycnometer is then refilled with distilled water to the same le+el as efore

dried on the outside and weighed (C).

"0. The water from the sample is remo+ed y decantation and the sample is dried in

the o+en at "00 0C to ""0 0C for ,1 @ "=, hours cooled and weighed (D).

Observation Table:Determination no. $ample " $ample ,

". eight of sample ta#en g,. eight of saturated and surface dry aggregate (C) g3. eight of pycnometer @ sample @ water ( ) g1. eight of pycnometer @ water (!) g

. eight of o+en dry sample (D) g5. $pecific gra+ity D=C ( !)*. pparent specific gra+ity D=D ( !)

Result:". +erage +alue specific gra+ity P,. +erage +alue pparent specific gra+ity P


WORKABILITY BY SLUMP AND COMPACTING FACTOR TESTS

Object: To Determine or#a ility y $lump and Compacting /actor Tests."5


17/28

Apparatus: 2ould in the from of a frustum of a cone tamping rod through trowel G.;.

'lain $heet 'latform and eighing 2achine.

Theory: or#a ility is the case with which concrete can e mi ed handled and

compacted. s per ;$; it is the property of concrete which determines the amount of

useful internal wor# necessary to produce full compaction. /or full compaction concrete

mi possesses three properties. 2o ility cohesi+eness during mo+ement of mi and the

a sence of harshness in offering smooth surface finish to trowelling.

;n slump test the wor#a ility is measured y slump of concrete. This test is suita le for

lean concretes.

;n compacting factor test concrete is allowed to fall through a standard height. The

degree ratio i.e. the ratio of density actually achie+ed in the test to density of concrete

fully compacted. Thus it is rational method than slump test and suita le for dry mi eswith low slump.

Procedure:(i) ;nternal surface of mould is cleaned first.

(ii) Ta#e ,#g Cement 1#g /ine ggregate -#g Coarse ggregate and mi first

C @/ and then cement with aggregates.

(iii) Mse water cement ratio 0.50 and ma#e the mi .

(i+)/ill the mould in three layers each layer tamped , times y tamping rod.(+) 6emo+e mould y 6aising gently.

(+i)2easure slump after mould is remo+ed y scale.

"*


18/28


19/28

TENSILE STRENGTH OF CONCRETE BY MODULUS OF RUPTURE

Object: To Determine Tensile $trength of Concrete y 2odulus of 6apture.

nd to Determine Tensile $trength of Concrete y $plit Cylinder Test.

Apparatus: 2ould ("0 "0 0cm) Vi rator Tamping !ar V. Testing 2achine Trowel

etc. " cm. dia and 30cm long.

Theory: The #nowledge of tensile strength in concrete is of +alue in estimating the load

under which crac# will de+elop. The a sence of crac#ing is of considera le importance in

maintaining the continuity of a concrete structure and pre+enting corrosion of

reinforcement.

2a imum Tensile stress reached in the ottom fi re of the test ean is #nown as

2odulus of rupture.

Procedure:

". 'repare moulds y applying oil to inside surfaces.

,. /or !ean Cylinder Cement (*#g) / C P ">,>1 w=c 0.5

3. /irst prepare dry mi of C and / and then mi cement and finally add water.

1. /ill the moulds in three layers each layer tamped y tamping rod , times.

. Leep the moulds in moist air of relati+e humidity for ,1 hours. fter this period

the specimens are remo+ed from the moulds and immediately immersed in clear

fresh water and #ept prior to testing.

Test #or Tensile Strength

5. 'lace the specimen in testing machine such that the load shall e applied to the

upper most surface as cast in mould along two lines spaced "3.33cm for 0cm

long ean. The a is of load de+ice.

*. pply load carefully without shoc# Q"-0#g=min. for "0cm specimen till

specimen fails. The appearance of fractured faces of concrete and any usual

features in the type of failure should e noted.

"J


20/28

'=, '=,

'=,'=,

"33

100

(

d

@ $./.D.

!.2.D.

'

'?P30C2

D P "

) C 2

$'?;T T8$T /E6 CR?;ND86

Now modulus of rapture is gi+en y

f P p " = d, if aS ,0cm for " cm specimen or aS"3.3 for "0cm specimen.

f P 3p " = d, if aS ,0cm for " cm specimen or aS"3.3 for "0cm specimen.

here

a P distance in cm etween the line of fracture and nearer support measured on

concrete line of specimen.

P width of specimen (cm)

d P depth of specimen (cm)

p P ma imum load applied to the specimen (#g)

l P length of specimen on which it is supported.

-. 'lace the cylinder in such a way it is supported throughout its length at lower andupper places. Now apply load and note the load at which cylinder splits in two

portions let it e p

Tensile $trength P ,p = D?

Test two specimen are at 3 day and another after * days.

'repare concrete mi ">,>1 y weight using w=c ratio of 0.5 0. 0. 0 etc.

Observation Table:$pecimen !ean Cylinder ;dentification mar# Concrete mi w=c ratio'roduced onTested on

ge of testing6upture = split load2odulus of rupture= split tensile strength

+erage +alue

,0


21/28

Result:

Discussion:

". The results with +alues specified y ;$;.

,. ;mportance of two tests i.e. tensile strength y modulus of rupture and y split

cylinder test.


,"


22/28

EFFECT OF WATER CEMENT RATIO ON A CONCRETE MIX

Object: To study the effect of water cement ratio on a concrete mi .

Apparatus: Cu e 2oulds Vi rator Temping 6od Trowel Concrete 2i ture.

Theory: ater cement ratio is main controlling factor in the design of concrete mi es.

ccording to rams ?aw for any gi+en conditions of test the strength of wor#a le

concrete mi is dependent only on the water cement ratio. ater Cement ratio affects

dura ility and wor#a ility of concrete. 2ore the water cement ratio less dura le and

strong will e concrete ut wor#a ility will increase with water cement ratio.

Procedure:". 'repare " cm cu e moulds y cleaning and oiling the inner surfaces.

,. 'repare concrete mi ">,>1 y weight using w=c ratio of 0. 0.1 0.10 etc.

3. Cure the moulds for ,1 hours in an en+ironment of J0% relati+e humidity and

then cure the cu es in water for ,- days till they are tested.

1. During testing use rate of loading Q "10#g=cm , =min. Note down the rea#ing

load and type of failure.

. Mse for Two Cu es (" cm) 2i ">,>1

(Cement ,. #g /ine ggregate .0#g and Coarse aggregate "0#g)

Observation Table:$l.

No.;dentification2ar#

ater Cement6atio Msed

ge ofTesting

/ailure ?oad Compressi+e$trength

Discussion:

". 8ffect of water cement ratio on strength wor#a ility.

,. Aow water cement ratio can e reduced without affecting wor#a ility.

Re#erences:

". $' ,3.,. Concrete Technology y Vi irani and $.'. Chandola.3. Concrete Technology y .2. Ne+ille.

,,


23/28

CONCRETE MIX DESIGN USING FLYASH

Object: To study the compressi+e strength of concrete mi consisting of fly ash

Apparatus: Cu e 2oulds Cylindrical moulds Vi rator Temping 6od Trowel Concrete

2i ture. "00 ton compression testing machine.

Theory: /ly ash can e used to replace the cement. ;t has good inding properties. Thefly ash can e mi ed in different proportions. ;t can sol+e the en+ironmental pro lem of

disposing of fly ash.

Procedure:". 'repare " cm cu e moulds and Cylindrical mould " cm dia. 30cm high as per ;$

> "5 y cleaning and oiling the inner surfaces.


6eplace cement y flyash as % "0% ,0% and 30%3. Cure the moulds for ,1 hours in an en+ironment of J0% relati+e humidity and

then cure the cu es in water for * days and ,- days till they are tested.



. Mse for Two Cu es (" cm) and Two Cylindrical mould " cm dia. 30cm high

2i ">,>1


No.;dentification

2ar# % of /ly sh ge of

TestingCompressi+e

$trength6emar#

Discussion:

". Aow is the cylinder strength related to the cu e compressi+e strength.


,3


24/28

CONCRETE MIX DESIGN USING ISF Slag

Object: To study the compressi+e strength of concrete mi consisting of ;$/ $lag

Apparatus: Cu e 2oulds Cylindrical moulds Vi rator Temping 6od Trowel Concrete

2i ture. "00 ton compression testing machine.

Theory: ;$/ slag can e used to replace the sand= fine aggregates. The ;$/ slag can emi ed in different proportions. ;t can sol+e the en+ironmental pro lem of disposing of

;$/ $lag.

Procedure:

". 'repare " cm cu e moulds and Cylindrical mould " cm dia. 30cm high as per ;$

> "5 y cleaning and oiling the inner surfaces.


6eplace fine aggregate y ;$/ $lag as ,0% 10% and 50%


then cure the cu es in water for * days and ,- days till they are tested.



. Mse for Two Cu es (" cm) and Two Cylindrical mould " cm dia. 30cm high

2i ">,>1


No.;dentification

2ar# % of ;$/ $lag ge of

TestingCompressi+e

$trength6emar#

Discussion:

". Aow is the cylinder strength related to the cu e compressi+e strength.


,1


25/28

TENSILE STRENGTH OF FIBRE REINFORCED CONCRETE

Object: To Determine Tensile $trength of /i er Concrete

Apparatus: 2ould ("0 "0 0cm) Vi rator Tamping !ar V. Testing 2achine Trowel

etc. " cm. dia and 30cm long.

Theory: The #nowledge of tensile strength in concrete is of +alue in estimating the load

under which crac# will de+elop. The fi ers in the concrete may enhance the tensile

strength of the concrete. The a sence of crac#ing is of considera le importance in

maintaining the continuity of a concrete structure and pre+enting corrosion of

reinforcement.

Procedure:

". 'repare moulds y applying oil to inside surfaces.

,. /or !ean Cylinder Cement (*#g) / C P ">,>1 w=c 0.5. dd the steel fi ers in

the ratio of "% ,% and %.

3. /irst prepare dry mi of C and / and then mi cement and finally add water.

1. /ill the moulds in three layers each layer tamped y tamping rod , times.

. Leep the moulds in moist air of relati+e humidity for ,1 hours. fter this period

the specimens are remo+ed from the moulds and immediately immersed in clear

fresh water and #ept prior to testing.

Test #or Tensile Strength

5. 'lace the specimen in testing machine such that the load shall e applied to the

upper most surface as cast in mould along two lines spaced "3.33cm for 0cmlong ean. The a is of load de+ice.

*. pply load carefully without shoc# Q"-0#g=min. for "0cm specimen till

specimen fails. The appearance of fractured faces of concrete and any usual

features in the type of failure should e noted.

,


26/28

'=, '=,

'=,'=,

"33

100

(

d

@ $./.D.

!.2.D.

'

'?P30C2

D P "

) C 2

$'?;T T8$T /E6 CR?;ND86

Now modulus of rapture is gi+en y

f P p " = d, if aS ,0cm for " cm specimen or aS"3.3 for "0cm specimen.

f P 3p " = d, if aS ,0cm for " cm specimen or aS"3.3 for "0cm specimen.

here

a P distance in cm etween the line of fracture and nearer support measured on

concrete line of specimen.

P width of specimen (cm)

d P depth of specimen (cm)

p P ma imum load applied to the specimen (#g)

l P length of specimen on which it is supported.

-. 'lace the cylinder in such a way it is supported throughout its length at lower and

upper places. Now apply load and note the load at which cylinder splits in two

portions let it e pTensile $trength P ,p = D?

Test two specimen are at 3 day and another after * days.

'repare concrete mi ">,>1 y weight using w=c ratio of 0.* 0.5 0.50 etc.

,5


27/28


28/28

FFECT OF STEEL FIBERS ON COMPRESSIVE STRNGTH OF CONCRETE

Object: To study the effect of steel fi ers on a concrete mi .

Apparatus: Cu e 2oulds Vi rator Temping 6od Trowel Concrete 2i ture.

Theory: The steel fi ers are used to increase the tensile strength of concrete and to

reduce the shrin#age crac#s.. Their effect on compressi+e strength also need to e

studied.

Procedure:". 'repare " cm cu e moulds y cleaning and oiling the inner surfaces.

,. 'repare concrete mi ">,>1 y weight using w=c ratio of 0.* 0.5 0.50 etc.


then cure the cu es in water for ,- days till they are tested.



. Mse for Two Cu es (" cm) 2i ">,>1

(Cement ,. #g /ine ggregate .0#g and Coarse aggregate "0#g)


No.;dentification2ar#

% of steel fi er ge ofTesting

/ailure ?oad Compressi+e$trength

Results


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