CONCRETE

LABORATARY MANUAL

CIVIL ENGINEERING

SUB:CODE-404

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CONTENTS

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S.NO . TITLE PG.NO _________________________________________________________________

1. FINENESS TEST ON CEMENT

2. BULKING OF SAND.

3. TEST ON AGGREGATE FOR CONCRETE-SIEVE ANALYSIS

4. SPECIFICGRAVITY OF CEMENT

5. PROPERTIES OF FRESH CONCRETE-WORKABBILITY.A.SLUMP TEST

6.CONSISTENCY TEST ON CEMENT

7.COMPERSSIVE STRENGTHON CONCRETE CUBES ________________________________________________________________

Instructions.1.

Write observations, tables, diagrams, Specimen calculations

in the blank left side of the journal and others to the right.

FINENESS TEST ON CEMENT

Experiment No.1

DATE : _________________________________________________________________

Aim

To determine the fineness of agiven sample of cement

Theory

Strength development of concrete is the result of the reactions of

water with cement particles.The reactions always start with the cement

available at the surface of the particles.Thus larger the surface area

available for reaction greater the rate of hydtration.Rapid development

of strength requires grater degree fineness.however too much fineness

is alsoconsiderable.finer cement deteriorates more quickly when

exposed to air and and is likely to cause more shrinkage,but less prone

to bleeding

Apparatus

1)Weighing balance

2)Is test sieve 90 micron

3)Brush and handle

4)Tray and trowel

Procedure

1)weigh accurately 100g of cement and place it on astandared Is sieve

90 micron

2)Breakdown any air set lumps in the sample with fingers but donot run

on the sieve.

3)Continuosly sieve the sample by holding the sieve in both hands and

giving a gentle wrist motion or mechanical sieve shaker may be uesed

fo r this purpose

4)Weigh the residue left after 15 minutessieving this residue shall not

exeed the specified limits

Result

Fineness of cement=10%

Discussion

For ordinary portland cement fineness shouldnot be more than

10% of orginal weight.

BULKING OF SAND

Experiment No.2

DATE : _________________________________________________________________

Aim

To determine the moisture content at which bulking of sand

occurs

Apparatus

Measuring jar,weighing balance,mixing pan,trowel….etc

Principle

Percentage of bulking of sand=V-Va/Va X100

V=Volume of bulked sand Va=Actual volume of sand

Procedure

1)Take200 ml of sand in measuring jar and take the weight of sand

2)Add water is one percentage of the weight(sand) and mixed

thoroughly and measure the increasing volume

3)Add 2%,3%,4%..........and theproces is repeated for number of times

and each increase in volume is taken

4)After the increase in volume there is a slow decreasein volume ,then

pure water is added to the sand to increase it.That will give orginal

volume

5)When water added the volume ofsand increased and an optimum

volume of sand reached

6)A graph is ploted by taking percentage of increase in volume

and percentage of bulking

Observations:

% of

moisture

Volume of

water(ml)

Volume of

bulked sand

% of bulking

Result:

The maximum bulking of sand takes place at moisture content is

………%

Water content at which maximum bulking occure…..%

Inference:

Bulking of sand increases with increase in moisture content up to

a certain limit beyond that further increase in moisture content

decrease the volume of bulked sand.

TEST ON AGGREGATES FOR CONCRETE – PARTICLE SIZE

DISTRIBUTION

SIEVE ANALYSIS Experiment No.3

Date :

________________________________________________________________

Aim:

To determine the particle size distribution of fine aggregate by conducting dry sieve

analysis. Also identify to which zone, the given sample of aggregate belong.

Theory:

The aggregate most of which passes IS 475mm sieve is classified as fine aggregate

and retained on 4.75mm sieve is classified as coarse aggregate can be obtained. A

sample may be well graded, poorly graded or uniformly graded. The term D10 or

effective size represents sieve opening such that 10% of the particle are finer than this

size. Similarly D30 and D60 can also be obtained from the graph. Then, uniformity

coefficient

Cu = D60/D10

Fitness Modulus is a term indicating the coarseness or fitness of the material. It is

obtained by adding the cumulative property percentages of aggregate retained on each

of the sieve and dividing them by 100

Apparatus:

• Balance

• Sieves- sieve of the size given in table 1 conforming to IS: 460-1962

specifications for tests series shall be used.

• Sample- the weight of sample available shall not be less than the weight given in

Table 2

Table 1

I.S SIEVES FOR ANALYSIS OF AGGREGRATES FOR CONCRETE

Type Sieve designation

Square hole, Perforated plate 80mm,63mm,50mm,40mm,31.5mm,25mm, 20mm,16mm,12.5mm,10mm,6.3mm,4.75mm

Fine mesh, Wire cloth 3.35mm,2.36mm,1.18mm, 600micron,300micron,150micron,75micron

Observations & Calculations

I.S Sieve size Percentage passing by weight for

Grading zone 1 Grading zone2 Grading zone3 Grading zone4

10mm 100 100 100 100

4.75mm 90-100 90-100 90-100 95-100

2.36mm 60-95 75-100 85-100 95-100

1.18mm 30-70 55-90 75-100 90-100

600micron 15-34 35-59 60-79 80-100

300micron 5-20 8-30 12-40 15-50

150micron 0-10 0-10 0-10 0-15

Fitness modulus

4.0-2.41 3.37-2.10 2.78-1.71 2.25-1.35

Sample:_________________________________________

Sieve

Size

mm

Col 1

Col 2

Col 3

Col 4

Col 5

Sieve

Tare

grams

Mass of

Sieve and

Aggregate

grams

Mass

Retained

(Col 2 -

Col 1)

grams

Cumulative

Mass

Retained

( of

consecutive

rows in Col

3)

grams

Cumulative

Percent

Retained

(Col 4 / A *

100)

%

Cumulative

Percent

Passing

(100 - Col

5)

%

37.5

25

19

12.5

9.5

4.75

2.36

1.18

0.6

0.3

0.15

0.075

Minus

0.075

(Pan +

C)

TOTAL

Fineness modulus (F.M) = ∑ (Cumulative % retained)/100

Table 2

MINIMUM WEIGHT OF SAMPLE FOR SIEVE ANALYSIS

Maximum size present in substantial proportions(mm)

Minimum weight of sample to be taken for sieving (kg)

63 50

50 35

40or31.5 15

25 5

20or16 2

12.5 1

10 0.5

6.3 0.2

4.75 0.2

2.36 0.1

Procedure

• The sample is brought to an air- dry condition before weighing and sieving either

by drying at room temperature or by heating at a temperature of 100 ̊ to 110 c

• The dried sample is weighed.

• The weighed sample is placed on the sieve and sieved successively on the

appropriate sieves starting with the largest.

• Each sieve is shaken separately over a clean tray until not more than a trace

passes, but in any case for a period of not less than 2 minutes. The Shaking is

done with a varied motion, backward and anti clockwise. Lumps of fine materials

if present may be broken by gentle pressure with fingers against the side of the

sieve.

• At the end of sieving, 150 microns and 75 micron sieves are cleaned from the

bottom by light brushing with fine hair brush.

• On completion of sieving, the material retained on each sieve together with any

material cleaned from mesh, is weighed.

• This procedure is done for both coarse and fine aggregates.

• A curve is drawn between percentage passing and the sieve size for fine

aggregate.

Result :

Fine aggregates Result

Effective size D10 = micron

Uniformity coefficient=

Fineness modulus =

Zone =

Discussion:

SPECIFIC GRAVITY OF CEMENT

Experiment No.4 Date : _______________________________________________________________

Aim:

To determine the specific gravity of cement

TheOry:

The specific gravity of cement is the ratio of the weight of a given

volume of substance to the weight of an equal volume of water.It is a

mere number and it denotes howmany times a substance is heavy as

water

Specific gravity of substance=wt density of a substance/wt density of

water

To find the specific gravity of cement,it is requeirred to find the weight

of a certain volume cement and the weight of an equal volume of

water.As cement reacts with water its specific gravity is determined

with reference to a non reactive liquid like kerosene

Specific gravity of cement w,r.to kerosine=wt of cement/wt of an equal

volume of kerosene

To find the specific gravity of kerosene w.r.t water=wt of kerosene/wt of

equal volume of water

The specificgravity of cement is the calculation by multiplying specific

gravity of cement w.r.to kerosene with specific gravity of kerosene w.r.t

water

Procedure:

1)Clean dry and wegh specific gravity bottle

2)Take certain quantity of cement (about one fourth of the bottle)in the

bottle and weigh(w2)

3)Pour kerosene over the cement to fill the bottle and find the total

weight(w3)

4)Clean the bottle thoroghly with kerosene and fill the bottle with

kerosene and weigh (w4)

5)Finally clean the bottle with water and weigh(w5)

Tabulation:

Weight of bottle(w1)=

Weight of bottle+cement(w2)=

Weight of bottle+cement+kerosene(w3)=

Weight of bottle+kerosene filling bottle(w4)=

Weight of bottle+water filling bottle(w5)=

Calculation:

Weight of cement w.r to kerosene(wc)=w2-w1

Weight of an equal volume of kerosene(wk)=(w4-w1)-(w3-w2)

Specific gravity of cement w rto kerosene(csk)=Wc/Wk

Weight of kerosene filling bottle (Wk)=w4-w1

Weight of an equal volume of water(mw)=w5-w1

specific gravity of kerosene wr to water(ksw)=Wk/mw

There for specific gravity ofcement wr to water=csk X ksw

Result:

Specific gravity of cement w.r.to water=

As per Is specification specific gravity of cement in between 2.4-

2.8

Discussion:

PROPERTIES OF FRESH CONCRETE – WORKABILITY

• Slump Test

Experiment No. 5

Date :

_____________________________________________________________________

Aim: To determine the slump test of the prepared mix and study it’s characteristics

Theory:

Unsupported fresh concrete flows to the sides and a sinking in height takes place. This vertical settlement is known as slump. In this test fresh concrete is filled into a mould of specified shape and dimensions, and the settlement or slump is measured when

supporting mould is removed. Slump increases as water-content is increased. For different works different slump

values have been recommended. The slump is a measure indicating the consistency or workability of cement concrete. It gives an idea of water content needed for concrete to be used for different works. A concrete is

said to be workable if it can be easily mixed, placed, compacted and finished. A workable concrete should not shown any segregation or bleeding. Segregation is said to occur when coarse aggregate tries to separate out from the finer material and a concentration of coarse aggregate at one place occurs. This results in large voids, less durability and strength. Bleeding

of concrete is said to occur when excess water comes up at the surface of concrete. This causes small pores through the mass of concrete and is undesirable. By this test we can determine the water content to give specified slump value. In this test water content is varied and in each case slump value is measured till we arrive at water content giving the required slump value. This test is not a true guide to workability. For example, a harsh mix cannot be said to

have same workability as one with a large proportion of sand even though they may have the

same slump.

Apparatus

Iron pan to mix concrete, slump cone, spatula, trowels, tamping rod and graduated cylinder.

Slump test apparatus

Procedure

Four mixes are to be prepared with water-cement ratio (by mass) of 0.50, 0.60, 0.70 and

0.80, respectively, and for each mix take 10 kg of coarse aggregates, 5kg of sand and 2.5kg of cement with each mix proceed as follows

1) Mix the dry constituents thoroughly to get a uniform colour and then add water 2)

Place the mixed concrete in the cleaned slump cone mould in 4 layers, each

approximately ¼ of the height of the mould. Tamp each layer 25 times with tamping rod distributing the strokes in a uniform manner over the cross-section of the mould. For the second and subsequent layers the tamping rod should penetrate in to the underlying layer. 3) Strike off the top with a trowel or tamping rod so that the mould is exactly filled. 4) Remove the cone immediately, raising it slowly and carefully in the vertical direction. 5) As soon as the concrete settlement comes to a stop, measure the subsidence of

concrete in mm which will give the slump. Note: Slump test is adopted in the laboratory or during the progress of work in the field for determining consistency of concrete where nominal maximum size of aggregate does not exceed 40mm

Any slump specimen which collapses or shears off laterally gives incorrect results and if this occurs the test is repeated, only the true slump should be measured.

Observations & Calculations

Result: The test values are tabulated below

Water content Slump Workability

Discussions:

CONSISTENCY TEST ON CEMENT

Experiment No.6

DATE : _____________________________________________________________________

Aim

To determine the percentage of water for normal consistency

Theory

For findingout initial setting time ,final stting time and soundness

of cement a standared parameter known as standared consistency has

to beused

Since defferent batches of cement deffer in fineness,pastes with

some water content may deffer in consistency when first mixed.For this

reason the consistency of the paste is standardized by varying the

water content untill the paste has a given resistance to penetration.

Standared or normal consistency of a cement paste is defined as

that consistency(degree of wetness) which will permit the vicat plunger

to penetrate the cement paste to a point 5-7mm from the vicat mould

when the cement paste is tested within 3-5 minutes after it is mixed

with water.

Apparatus

1)Vicats apparatus with a 10mm diameter plunger and a needle of

1mm square section

2)Vicat mould

3)Non porous pate

4)Measuring jar

5)Trowel

Vicats apparatus

Procedure

1)The mould and the non porous plate are washed,cleaned and dried

2) 400g of the given sample of cement is kept on the non porous plate

3) 30% water by weight of cement is added very care fully to dry

cement and mixed thoroughly to get a neat cement paste.care should

be taken that the time of gauging is not lessthan 3 minutesand and not

morethan 5minutes.the gauging time shall be counted from he time of

adding water to the dry cement until commencing to fil the mould

4)The vicat mould is placed on the non porous plate and is filled with

the prepared cement paste with trowel,the surface is smoothened is

level with the mould

5)By shaking mould slightly any air from the sample is expelled

6)The non porous plate and mould are placed under the plunger

7)The plunger is gently leveled to touch the surface of paste and then

the indicator is adjusted to show zero reading

8)The plunger is released quickly and allowed to penitrate in to the

paste

9)When the plunger comes to rest,the reading on the index scale is

noted

10)Several trial pastes are prepared with varying percentages of water

and the test is conducted untill the needle penetrated 5mm-7mm

above the bottom of the mould

Observations:

Si

no

Wt of cement

taken(g)

Volumeof water

added

Water added

as % of by

weight of dry

cement

Penetration

index reading

Result

Found standared or normal consistency of cement=

Discussion

The usual range of values being between26 and 33%

COMPRESSIVE STRENGTH OF CEMENT CONCRETE Exp No: 7

Date:

_____________________________________________________________________

Aim: To determine the cube strength of the concrete of given properties

Apparatus required: Moulds for the test cubes, tamping rods

Procedure.

1. Calculate the material required for preparing the concrete of given proportions

2. Mix them thoroughly in mechanical mixer until uniform colour of concrete is

obtained

3. Pour concrete in the oiled with a medium viscosity oil. Fill concrete is cube

moulds in two layers each of approximately 75mm and ramming each layer with

35 blows evenly distributed over the surface of layer.

4. Fill the moulds in 2 layers each of approximately 50mm deep and ramming each

layer heavily.

5. Struck off concrete flush with the top of the moulds.

6. Immediately after being made, they should be covered with wet mats.

7. Specimens are removed from the moulds after 24hrs and cured in water 28 days

8. After 24hrs of casting, cylinder specimens are capped by neat cement paste 35

percent water content on capping apparatus. After 24 hours the specimens are

immersed into water for final curing.

9. Compression tests of cube and cylinder specimens are made as soon as

practicable after removal from curing pit. Test-specimen during the period of their

removal from the curing pit and till testing, are kept moist by a wet blanket

covering and tested in a moist condition.

10. Place the specimen centrally on the location marks of the compression testing

machine and load is applied continuously, uniformly and without shock.

11. Also note the type of failure and appearance cracks.

Observations:

Specimen Trials Mean Value N/mm2

1 2 3

Load on cubes, KN

Result:

The compressive strength of cementconcreteis________________N/mm2