civil engineering materials -...

Department of Civil Engineering

City University of Science & Information Technology

Peshawar Pakistan.

Civil Engineering Materials Lab Manual

Prepared by: Humna Hamid Checked by: Habil Ahmed

Approved by: Prof Dr Atta Ullah Shah.

OBJECTIVES:

The objective of this course is to introduce the students with the Civil Engineering Construction

Materials. The primary emphasis of the course is on fundamental understanding of the

underlying principles of the topics that have been discussed in the lectures using various

experimental techniques, instruments and apparatus. This laboratory course involves the study of

instrumentation and philosophical content that should help to serve as a foundation for the future

professional career of Civil engineers. In general, there might not be a single unique answer to

the laboratory problems. Then, the student may determine the best 'answer' possible within the

framework of the equipment available, the estimated errors, etc. The teaching staff have all

solved similar problems before and can assist with the procedures and techniques required for the

successful completion of the experiment. Hence, success in the course will depend upon the

student's own initiative and ideas toward the problem solving in a given experiment. The

experimentation work is divided into four groups.

Tests for Cement

Tests for Fine Aggregates

Tests for Coarse Aggregates

Tests for Compressive Strength

This laboratory manual available to all students at the beginning of the semester contains the

detailed information about the experiment objectives with each having a brief introduction, a

short description of the facility, suggestions for summary and a few references. Students must

prepare themselves for the next scheduled experiment following the appropriate hand-out.

Teaching Assistants conduct brief quizzes before students are allowed access to the experimental

set-up to make sure students are ready. Students will not be allowed to perform the experiment

without satisfactory knowledge of the expected work in the laboratory.

LIST OF EXPERIMENTS:

SR.NO EXPERIMENTS Specification PAGE

NO

1 Gradation of Concrete Fine Aggregates ASTM C-136 5

2

Gradation of Concrete Coarse Aggregates ASTM C-136 9

3 Fineness of Hydraulic Cement by the Sieve #200.

ASTM C-430 12

4 Standard Test Method for Density, Specific Gravity and

Absorption of Fine Aggregate ASTM C-128 14

5 Standard Test Method for Density, Specific Gravity and

Absorption of Coarse Aggregate ASTM C-127 18

6 To find Organic Impurities in Sand ASTM C-40 20

7 Impact Value Test for coarse Aggregate 22

8

Standard Test Method for Normal Consistency of Hydraulic

Cement

ASTM C-187 25

9 Standard Test Methods for Time of Setting of Hydraulic

Cement by Vicat Needle ASTM C-191 27

10 Standard test method for slump of hydraulic cement concrete ASTM C-143 30

11 To determine the compressive strength of cement mortar 36

12 Compaction factor Test for workability of concrete 39

EXPERIMENT No #1

Gradation of Fine Aggregate by Sieve analysis (ASTM C-136)

OBJECTIVE: This test method covers the determination of the particle size distribution of fine aggregates by

sieving.

APPARATUS

Weighing machine, ASTM Standard sieve set, pan & electric sieve shaker.

Figure1: ASTM Standard sieve set

THEORETICALBACKGROUND: The purpose of the sieve analysis is to check the aggregate that we are using is suitable for use

and fulfill our requirement or not. If the requirements come between fines range then the

aggregate is suitable for use in any construction work. It also gives information about the

maximum number of size aggregates present in the sample. For fine aggregate the fines modulus

must be between 2.3 and 3.2.is recommended by ASTM. If else this value then the fine aggregate

is not suitable for use in any construction work

PROCEDURE:

1. Place the sieves on top of each other (#4, #8, #16, #30, #50, #100 and pan).

2. Place the highest Sieve No. on top and place below it the decreasing No of Sieve.

3. Now take sample as you required.

4. Take minimum 500g sample of fine aggregate.

5. Put the entire sample on top sieve and shake it.

6. The least time for shaking is 15 minutes.

7. After suitable shaking place the sample in the pan and weight it.

8. Continue the process till the last sieve.

9. Find the sample retained on each sieve.

RESULTS & CALCULATION

Now find the sample retained on each sieve by using formula:

Calculate % retained on sieve = Retained weight * 100

Total weight

Then calculate the cumulative % passing and cumulative % retained.

Finally calculate fines modulus by using formula = ∑Cumulative % retained

100

Plot the particle size distribution against the ASTM limits

Figure 1: ASTM Maximum & Minimum Limitations

Observation Table:

Sieve analysis of Fine Aggregate

Sieve

# Sieve

size

Weight

Retained

(gm)

%

retained

%

passing

Cumulative

% passing

Cumulative

%

Retained

ASTM Specs %

passing

Minimum Maximum

Pan 0 0

#100 2 10

#50 10 30

#30 25 60

#16 50 85

#8 80 100

#4 95 100

Fineness Modulus = ______________

EXPERIMENT No #2

Gradation of Coarse Aggregate by Sieve analysis

(ASTM C-136)

OBJECTIVE: This test method covers the determination of the particle size distribution of coarse aggregates by

sieving.

APPARATUS

Weighting machine, ASTM Standard sieve set, pan & electric sieve shaker.

Figure 2: ASTM Standard sieve set

THEORETICAL BACKGROUND:

The purpose of the sieve analysis is to check the aggregate that we are using is suitable for use

and fulfill our requirement or not. It also gives information about the maximum number of size

aggregates present in the sample.

PROCEDURE:

1. First place the sieves on top of each other.

2. Place the highest Sieve No. on top and place below it the decreasing no of Sieve No.

3. Now take sample as you required.

4. Take minimum 2000g sample of fine aggregate.

5. Put the entire sample on top sieve and shake it.

6. The least time for shaking is 15 minutes.

7. After suitable shaking place the sample in the pan and weight it.

8. Continue the process till the last sieve.

9. Find the sample retained on each sieve.


Now find the sample retained on each sieve by using formula:

% retained on sieve = retained weight * 100

Total weight

Then calculate the cumulative % passing and cumulative % retained.

Plot the particle size distribution against the ASTM limits

Sieve analysis of Coarse Aggregate

Sieve

#

Sieve

size

Weight

Retained

(gm)

%

retained

%

passing

Cumulative

% passing

Cumulative

%

Retained

ASTM Specs %

passing

Minimum Maximum

EXPERIMENT No #3

Standard Test Method for Fineness of Hydraulic Cement by

the 45-μm (No. 325) Sieve (ASTM C-430)

OBJECTIVE: This test method covers the determination of the fineness of hydraulic cement by means of the

45-μm (No. 325) sieve.

APPARATUS Weighting machine, sieve # 325, pan& electric sieve shaker.

Figure 1: ASTM sieve # 325 (45-μm)

PROCEDURE:

1. Take 100g sample of cement and put it in a sieve # 200.

2. Shake for 15 minutes.

3. After that weight the sample retained on the sieve.

4. If it comes 10g i.e. 10% of given sample weight then it is fresh because 90% has passed

through sieve # 200, otherwise not.


Take samples from various batches

Weight of Cement sample taken (W1) = ______________

Weight retained on Sieve (W2) = ______________

% of fines of Cement )100

W1

W2-W1(

= ______________

EXPERIMENT No # 4

Standard Test Method for Density, Specific Gravity and

Absorption of Fine Aggregate (ASTM C-128)

OBJECTIVE:

This test method covers the determination of the average density of a quantity of fine aggregate

particles (not including the volume of voids between the particles), the relative density (specific

gravity), and the absorption of the fine aggregate.

APPARATUS: Weighting machine, Water tank, Sieves, Oven


Depending on the procedure used, the density, in kg/m3 or lb/ft3 is expressed as oven-dry (OD),

saturated-surface-dry (SSD), or as apparent density. Likewise, relative density (specific gravity),

a dimensionless quality, is expressed as OD, SSD, or as apparent relative density (apparent

specific gravity). The OD density and OD relative density are determined after drying the

aggregate. The SSD density, SSD relative density, and absorption are determined after soaking

the aggregate in water for a prescribed duration.

Figure 1: Moisture Conditions of Aggregates

DAMP OR WET:

Aggregate in which the pores are filled with water and with free water also on their

surface.

SATURATED SURFACE DRY (SSD):

Aggregate in which the pores are filled with water but with no free water on the surface.

AIR DRY (AD):

Aggregate that has a dry surface but contains some water in the pores.

OVEN DRY (OD):

Aggregate that contains no water in the pores or on the surface.

DENSITY:

Density of material is defined as mass per unit volume. Density of water is 1000kg/m3,

1g/cc or 62.4lb/ft3.

SIGNIFICANCE OF DENSITY:

If a minimum density is specified, for example, in heavy weight concrete for nuclear

radiation shielding and the aggregates used in concrete have density less than the specified value

then the concrete used for nuclear radiation shielding will not be able to absorb nuclear

radiations and it will not fulfill its purpose.

SPECIFIC GRAVITY:

The specific gravity of an aggregate is the mass of the aggregate in air divided by the

mass of an equal volume of water.

SPECIFIC GRAVITY (OVEN DRY):

Specific gravity (oven dry) of an aggregate is the oven dry mass divided by the mass of a

volume of water equal to the saturated surface dry aggregate volume.

SPECIFIC GRAVITY (SATURATED SURFACE DRY):

Specific gravity (saturated surface dry) of an aggregate is the saturated surface dry mass

divided by the mass of a volume of water equal to the saturated surface dry aggregate volume.

SPECIFIC GRAVITY (APPARENT):

Specific gravity (apparent) of an aggregate is the oven dry mass divided by the mass of a

volume of water equal to that of the solid including the impermeable pores.

SIGNIFICANCE OF SPECIFIC GRAVITY:

The specific gravity of an aggregate is used in mixture proportioning calculations to find

the absolute volume that a given mass of material will occupy in the mixture. Absolute volume

of an aggregate is the volume of solid matter and internal pores excluding the spaces between the

particles. The absolute volume is used to calculate the volume of a batch of concrete.

In a given concrete mixture, substituting one aggregate with another of a different specific

gravity will cause the volume of concrete to change for the same batch mass. Because concrete is

often sold by volume, this change means that either the purchaser is receiving less concrete than

ordered or the producer is supplying more concrete than purchased. Specific gravity can also

indicate possible material contamination. Deleterious particle are often lighter than aggregate

particles and therefore a large amount of deleterious material in an aggregate sample may result

in an abnormally low specific gravity.

Absorption:

The increase in mass of aggregate due to water penetration into the pores of the particles

is called absorption.

Significance of Absorption:

To calculate the amount of mixing water in a concrete batch, it is necessary to know the

amount of water absorbed by the aggregates. If absorption value is not known then the total

water needed for concrete cannot be determined accurately.

PROCEDURE:

1. Partially fill the graduated cylinder with water.

2. Add 500g of saturated surface dry (SSD) fine aggregate in graduated cylinder.

3. Agitate the graduated cylinder to eliminate all air bubbles.

4. After eliminating air bubbles bring the water level in graduated cylinder to its calibrated

capacity.

5. Determine the total mass of the graduated cylinder, specimen and water.

6. Remove the fine aggregate from the graduated cylinder, dry in the oven at a temperature

of 110 degree centigrade, allow cooling in air at room temperature for 1 hour and

determining it’s mass.

7. Fill the graduated cylinder to its calibrated capacity with water and determine it’s mass.


Specific gravity (oven dry) = A/ (B + S – C)

Specific gravity (saturated surface dry) = S/(B+S – C)

Specific gravity (apparent) = A/ (B+A-C)

Absorption % = (S-A)/A x 100

Where

S = mass of saturated surface dry specimen (g)

A = mass of oven dry specimen (g)

B = mass of graduated cylinder filled with water to its calibrated mark (g)

C = mass of graduated cylinder filled with specimen and water to calibration mark (g)

EXPERIMENT No # 5

Standard Test Method for Density, Specific Gravity and

Absorption of coarse aggregate (ASTM C-127)

OBJECTIVE: This test method covers the determination of the average density of a quantity of coarse

aggregate particles (not including the volume of voids between the particles), the relative density

(specific gravity), and the absorption of the coarse aggregate.

APPARATUS Weighting machine, Water tank, Sieves, Oven

THEORETICALBACKGROUND:

Depending on the procedure used, the density (kg/m3or lb/ft3) is expressed as oven-dry (OD),

saturated surface-dry (SSD), or as apparent density. Likewise, relative density (specific gravity),

a dimensionless quantity, is expressed as OD, SSD, or as apparent relative density (apparent

specific gravity). The OD density and OD relative density are determined after drying the

aggregate. The SSD density, SSD relative density, and absorption are determined after soaking

the aggregate in water for a prescribed duration.

PROCEDURE:

1. Dry the test sample in the oven to constant mass at a temperature of 110 ± 5 degree

centigrade. Then cool it in air at room temperature for 1 to 3 h or until the aggregate has

reached a temperature that is comfortable to handle.

2. Immerse the coarse aggregate in water for 24 hours.

3. Remove the test sample from water and roll it in a large absorbent cloth to remove water

from surface.

4. Determine the mass of the test sample in saturated surface dry condition.

5. After determining the mass place the saturated surface dry sample in sample container,

determine its apparent mass in water.

6. Remove all entrapped air before determining its mass by shaking the container while

immersed.

7. Dry the test sample in oven at temperature of 110 degree centigrade, cool in air at room

for 1 to 3 hours or until the aggregate is comfortable to handle and determine its mass.


Specific gravity (oven dry) = A/(B-C)

Specific gravity (saturated surface dry) = B/(B-C)

Specific gravity (apparent) = A/(A-C)

Absorption % = (B-A)/B x 100

Where

A= mass of oven dry test sample in air (g)

B= mass of saturated surface dry test sample in air (g)

C= apparent mass of saturated test sample in water (g)

EXPERIMENT No # 6

To Find Organic Impurities in Sand (ASTM C-40)

OBJECTIVE:

This test method covers two procedures for an approximate determination of the presence of

injurious organic impurities in fine aggregates that are to be used in hydraulic cement mortar or

concrete. One procedure uses a standard color solution and the other uses a glass color standard.

APPARATUS: Thread, sand and colorless glass bottles having graduation marks at three points as follows

Standard color solution level – 75ml

Fine aggregate level – 130 ml

NaOH solution level - 200ml

THEORETICAL BACKGROUND: In order to check the organic impurities present in sand, we take standard solutions which gives a

yellowish color. Then a reference solution is taken. After mixing the reference solution in

graduated cylinder, given sample of sand is added to it and sand is added until it rises to height of

200 ml. Now this sample should be shaken. After shaking if the color is Fake / light than the

standard solution which is yellowish in color shows that the sand is free from organic impurities. If

however the color appears darker than the standard solution than there is a 50% of chances that

color changes due to ingredients like iron present in it. Which is not very harmful or there will be

organic impurities in it.

Reagent and standard color solution:

Reagent NaOH Solution: Dissolve 3 parts by mass of sodium hydroxide in 97 parts of water

Standard Color Solution: Dissolve potassium dichromate (K2Cr2O7) in concentrated sulphuric

acid at the rate of 0.25g/100ml of acid.

PROCEDURE: 1. Take 500g of sand.

2. Fill the glass bottle up to 130ml with sand.

3. Add sodium hydroxide solution until volume of sand and liquid is approximately 200ml.

Stopper the bottle, shake vigorously, and then allow the solution to stand for 24 hours.

4. After 24 hours fill a glass bottle to approximately 75 ml level with fresh standard color

solution.

5. Hold the bottle with test sample and the bottle with standard color solution side by side

and compare the color of the solutions.

6. Record whether the color of the test sample is lighter, darker or equal to the color of

standard color solution.

7. If the color of test sample is darker than standard color solution then the fine aggregate

under test contains injurious organic impurities.

RESULTS &CONCLUSIONS:

Leave the prepared reference solution in the lab for 24hrs and then observe the color of the

solution. Compare this color with the color of the standard solution.

EXPERIMENT No # 7

Impact Factor Test for Coarse Aggregates

OBJECTIVE: This determines the toughness of stones i.e., the resistance of the fracture under repeated impacts

may be called an impact test for aggregate.

APPARATUS:

Impact testing machine, cylindrical metal measure having internal diameter 75mm and depth

50mm for measuring aggregates. Tamping rod: 10mm in diameter and 230mm long, rounded at

one end. Sieve of sizes 12.5mm, 10mm, and 2.36mm for sieving the aggregates, Balance& Oven

with constant temperature between 1000C to1100C.

Figure 1: Impact value Test

THEORETICAL BACKGROUND: Toughness is the property of a material to resist impact. Due to loads, the aggregate are subjected

to the pounding action or impact and there is possibility of stones breaking into smaller pieces.

And so it should therefore be tough enough to resist fracture under impact.

PROCEDURE:

1. Take a test sample consisting of aggregates passing 12.5mm (0.5in) sieve and retained on

10mm (0.375in) sieve and dried in an oven for four hours at a temperature 1000oC to

1100oC and cooled.

2. Test aggregates are filled up to about one-third full in the cylindrical measure and tamped

25 times with rounded end of the tamping rod.

3. Further quantity of aggregates is then added up to two-third full in the cylinder and 25

stocks of the tamping rod are given.

4. The measure is now filled with the aggregates to over flow, tamped 25 times.

5. The surplus aggregates are struck off using the tamping rod as straight edge.

6. The net weight of the aggregates in the measure is determined to the nearest gram and

this weight of the aggregates is used for carrying out duplicate test on the same material.

7. The impact machine is placed with its bottom plate flat on the floor so that the hammer

guide columns are vertical.

8. The cup is fixed firmly in position on the base of the machine and the whole of the test

sample from the cylindrical measure is transferred to the cup and compacted by tamping

with 25 strokes.

9. The hammer is raised until its lower face is 380mm above the upper surface of the

aggregates in the cup, and allowed to fall freely on the aggregates.

10. The test sample is subjected to a total 15 such blows, each being delivered at an interval

of not less than one second.

11. The crushed aggregate is then removed from the cup and the whole of it sieved on the

2.36mm sieve (sieve no 8) until no further significant amount passes.

12. The fraction passing the sieve is weighed accurate to 0.1gm.

13. The fraction retained on the sieve is also weighed and if the total weight of the fractions

passing and retained on the sieve is added, it should not be less the original weight of the

specimen by more than one gram.

14. If the total weight is less than the original by over one gram the results should be

discarded and a fresh test made.

CALCULATIONS:

The aggregate impact value is expressed as the percentage of the fines formed in terms of the

total weight of the sample. .

Aggregate Impact Value =

LIMITATIONS

< 10% exceptionally strong,

10–20% Strong,

20–30% Satisfactory for road surfacing

> 35%Weak for road surfacing

EXPERIMENT No # 8

Standard Test Method for Normal Consistency of

Hydraulic Cement (ASTM C-187)

OBJECTIVE:

To determine the quantity of water for cement paste for normal consistency.

APPARATUS:

Vicat needle apparatus with plunger of 10mm dia, trowel, balance, etc.

THEORETICAL BACKGROUND: The percentage of water by weight of cement which produces a consistency which permits

plunger having diameter 10 mm, to penetrate up to depth of 5 to 7 mm above the bottom of

mould is called the normal consistency of cement paste.

PROCEDURE: 1. Take 400 gm of cement and place it in an enamel trough.

2. Add 25% of water in dry cement and mix it. The gauging time should not be less than 3

minutes and not more than 5 minutes. The gauging time is time consumed from adding of

water in dry cement to commencing to fill the mould.

3. After mixing properly, fill the vicat mould with this paste.

4. Level the surface of cement with the top of the mould.

5. Place the mould on the non-porous plate under the plunger of apparatus and adjust the

indicator in such a way that it shows zero reading when plunger touches the bottom of

mould (i.e., non-porous plate.)

6. Release the plunger and note down the reading.

7. If the penetration is less than the desired one then make another trial sample by

increasing water content and find the penetration.

8. Repeat the step 7 until the desired penetration, i.e. penetration up to 5 to 7 mm, above the

bottom is achieved.

OBSERVATIONS:

S.No Quantity of

Cement

Quantity of

Water

% of water by

weight

Penetration above

from bottom

Results Normal Consistency of cement paste=

Brand of Cement used : ___________________________

Normal Consistency : ___________________________

EXPERIMENT No #9

Standard Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle(ASTM C-191)

OBJECTIVE: To determine the initial and final setting time of cement.

APPARATUS Vicat’s needle apparatus, balance, stop watch, etc.

Figure 3: Vicat Apparatus with needle


Initial setting time is the time consumed from addition of water into dry cement to the instant at

which needle of 1 mm2 section fails to pierce the test sample to a depth of 5 mm from the

bottom. Final setting time is time consumed from addition of water into dry cement to the instant

at which needle of 1 mm2 with 5 mm dia attachment makes an impression on the sample but

attachments fails to make it.

PROCEDURE: 1. Weigh 400 gm of cement and place it in an enamel trough.

2. Add 0.85 P % water by weight of cement and mix it thoroughly, where P is the normal

consistency of cement.

3. Fill the mould with cement paste and level off the cement surface with the top of mould.

The gauging time should not be less than 3 minutes and should not be more than 5

minutes.

4. Place the mould on non-porous plate under the needle of apparatus.

5. Bring the needle in contact with the cement surface and release it.

6. Repeat the step (5) after every 2 minutes until the needle fails to pierce the sample for

about 5 mm measured from the bottom of the mould, note down this time. It is initial

setting time.

7. Replace the needle by needle with an annular attachment.

8. Bring the needle with attachment near the surface of cement and release it.

9. Repeat the step (8) until the needle makes an impression on surface and attachment does

not make impression.

10. Note down this time also.

OBSERVATIONS: Quantity of cement=

Normal Consistency=

Quantity of water=

Initial setting time=

Final setting time=

CALCULATION Quantity of water required = 0.85 x P x wt. of cement/100=

RESULT: Initial setting time=

Final setting time=

Brand of Cement used : ___________________________

Initial Setting Time (IST) : ___________________________

Final Setting Time (FST) : ___________________________

EXPERIMENT No # 10

Determine the SLUMP of concrete by SLUMP-TEST (ASTM C-

143)

OBJECTIVE: This test is performed to check the workability of freshly made concrete.

APPARATUS:

Slump test apparatus, 5/8” tampering rod, Measuring Balance

Mold in the form of the lateral surface of the frustum of a cone with the base 8 inch in diameter,

the top 4 inch in diameter and the height 12 inch. Tamping rod: A round, straight steel rod 5/8

inch in diameter and approximately 24 inch in length, having the tamping end or both ends

rounded to a hemispherical tip, the diameter of which is 5/8 inch.


Consistency is a term very closely related to workability. It is a term which describes the state of

fresh concrete. It refers to the ease with which the concrete flows. It is used to indicate the degree

of wetness. Workability of concrete is mainly affected by consistency i.e. wetter mixes will be

more workable than drier mixes, but concrete of the same consistency may vary in workability.

It can also be defined as the relative plasticity of freshly mixed concrete as indicative of its

workability. So concrete may have the following types of consistency:

PLASTIC CONSISTENCY:

When it can be shaped into a ball between the palms of hands and adheres to the skin.

SEMI-FLUID CONSISTENCY:

This cannot be rolled into a ball but spreads out without affecting the cohesion of the

constituents so that segregation doesn’t take place.

FLUID CONSISTENCY:

Which spreads out rapidly and segregation takes place.

Thus different degree of workability is required at different occasions. If the structure is RCC

and the steel bars too much close to each other than high workability is required i.e. fluid

consistency. While where the inter bars space is large than concrete of semi-fluid or plastic

consistency is required

Figure 1: Slump Apparatus

PROCEDURE:

1. Prepare a mixture of concrete having ratio of 1:2:4. That is one part of cement, two parts

sand, and four parts of crush.

2. For this first of all determine the volume of the cone in cubic feet.

3. It is determined by taking the mean diameter of the cone and with it finding the area of

the cross section of cone.

4. Then multiplying it with the height of the cone which is 1 foot, will give the volume of

the cone.

5. This is the volume of concrete which have to be prepared so that the cone is fully

compacted.

6. Then determine the total weight of the concrete, as the specific weight of concrete is 150

lb/ft3.

7. Then determine the weight of cement by multiplying the weight of concrete by 1/7, as

cement is one part out of total 7 parts.

8. Then determine the weight of sand by multiplying the weight of concrete by 2/7, as sand

is two parts out of total 7 parts.

9. Then determine the weight of crush by multiplying the weight of concrete by 4/7, as

crush is four parts out of total 7 parts.

10. After calculation of dry ingredients, calculate the amount of water as is given in the

ASTM Standard water-cement ratio. For 1:2:4 mixture the water-cement ratio is 0.6, so

for weight of water to be added, multiply this ratio with weight of cement.

11. After calculation of weights make a homogeneous mixture of dry ingredients, and then

add water carefully to make a paste.

12. Then take the slump-test apparatus and clean it from inside also apply oil to it and to the

bottom surface.

13. Then place it on the smooth metallic surface, and fix it firmly.

14. Then put one third of the concrete in the cone and press it with the help of a 5/8 inch,

round-ended, tampering rod.

15. It should be tampered 25 times.

16. Then add the second one-third portion of concrete, and also tamper it 25 times with the

help of tampering rod.

17. At last add the remaining one-third portion, and also tamper it 25 times.

18. For the upper surface to be smooth work it with float, so that during measurement of

slump it is easy to take correct readings.

19. Immediately after filling the cone is slowly lifted, and the unsupported concrete will now

slump, hence the name of the test. “The decrease in the height of the centre of the

slumped concrete is called slump”.

Figure 2: Slump measurement

RESULTS: The slump test gives the following three results:

TRUE-SLUMP: if the concrete subsides evenly then it is called true-slump, and is aimed

to be calculated.

SHEAR-SLUMP: If one half of the cone slides down, it is called shear-slump and is

difficult to measure. It occurs in harsh mixes (mixes deficient in fine aggregate).

COLLAPSE-SLUMP: If the concrete slides down as soon as the mould is removed, it is

known as collapse-slump. It occurs in very wet mix.

Figure 3: Type of Slump

CALCULATIONS:

Ratio of the concrete = 1:2:4

Sum of the ratio of concrete =1+2+4 = 7

Volume of the cone:

Mean diameter of the cone = Dm = 4+8/2 = 6 inch

Area of the cone =Ac = π*( Dm) 2 / 4

= π/4 *(6/12)2

= 0.1963 ft2

Volume of the cone = VC = 0.1963 ft2 * 1 ft

= 0.1963 ft3

Specific weight of concrete = γcon = 150 lb/ ft3

Weight of concrete = Wcon = γcon * Vc

= 150 * 0.1963

= 29.44 lb

Weights of dry materials:

Weight of cement = Wcem = 1/7 * Wcon

=1/7 * 29.4 = 4.2 lb ≈ 4 lb

Weight of sand = Wsand = 2/7 * Wcon

= 2/7 * 29.4 = 8.44 lb ≈ 8 lb

Weight of crush = Wcrush = 4/7 * Wcon

= 4/7 *29.4 = 16.82 lb ≈ 16 lb

Weight of water:

Ratio of concrete = 1:2:4

ASTM-Standard water-cement ratio = w/c = 0.6

Weight of water = Water = 0.6 * Wcem

= 0.6 * 4

= 2.4 lb

Standard values of slump:

Description Slump in inches

Concrete for road construction ¾ to 1.5

Slabs 1 to 2

Normal RCC sections, e.g. slabs, beams, columns,

walls etc. 2 to 6

Thin RCC structures 4 to 7

Vibrated concrete ½ to 1

Mass concrete 1 to 3

OBSERVATIONS:

Slump of the concrete = ______ inch

COMMENTS:

_____________________________________________________________________________________

EXPERIMENT No # 11

To Determine the Compressive Strength of cement mortar

(ASTM C-)

OBJECTIVE:

To determine the compressive strength of concrete.

APPARATUS:

Compression Testing Machine, Measuring Balance, Steel Moulds

THEORETICAL BACKGROUND: Cement is usually subjected to compressive stresses when used in the form of concrete or mortar.

Mortar is a mixture of cement and sand in a specified ratio on which the strength of the mortar

depends. If the mortar is weak then also its compressive strength is very low but if the mortar is a

strong one then its compressive strength is also very high. The mixture of sand and cement in

water is generally weak in tension and is strong in compression that is why when the concrete is

subjected to tensile forces then it is provided with steel rods in area of tension that is why it is

then called as reinforced concrete. Therefore it is obvious the mortar will be strong in

compression as compared to tension.

Mortar is generally used for brick masonry and plastering. In first case the mortar is subjected to

very high compressive loads such as the load of the wall above it, therefore it is very much

necessary to test the mortar for its compressive strength. For this purpose required cement-sand

mixture is prepared before its use and after a certain period of curing it is tested. The strength of

the mortar depends upon the fineness of cement, the gradation of sand and the most important

factor which water-cement ratio. If any one of the above factors be not according to the ASTM-

Standard then the strength of mortar is badly affected.

The standards of ASTM are provided for different ratios of mixture with which the test results

are compared and then decided for its use. These values are taken when the mortar is just

removed from curing.

PROCEDURE:

1. Prepare a mixture of cement and sand having ratio of: 1:3. That is one part of cement and

three parts sand.

2. We take the weight of cement equal to 200 grams and therefore the weight of sand equal

to 300 grams. This will make a 1:3 mortar.

3. Then calculate the amount of water for this ratio according to the ASTM standards.

4. This is 10% of the weight of total aggregate.

5. After calculation of weights make a homogeneous mixture of dry ingredients, and then

add water carefully to make a paste.

6. After this take the two inch cube mould and clean them thoroughly from inside and if

possible also apply some oil to the inner surface so that during removal of mould the

cubes are not damaged.

7. Also fix them tight so that during compaction it is easy to compact.

8. Then fill one third of the mould with mortar and press it with the help of a 5/8 inch,

round-ended, tampering rod.

9. It should be tampered 25 times.

10. Then fill the second one-third potion of mould, and also tamper it 25 times with the help

of tampering rod.

11. At last fill the remaining one-third portion, and also tamper it 25 times.

12. Adopting the same procedure as before, make six cubes of mortar so that we can take the

average of their strengths.

13. For the upper surface to be smooth work it with a float.

14. Then keep it is open air for one day.

15. Cure three of them for three days and the remaining three for six days by keeping them

immersed in water.

16. After curing of the cubes take them out of the moulds carefully and then bring them for

testing on compression machine.

17. Now place the test specimen in the compression machine & apply load to the test

specimen continuously and uniformly throughout the compression test.

18. As the load is applied on the cube it will develop cracks after certain load.

19. Discontinue the application of load when the cube has been crushed or just cracks are

developed in it.

20. Take out the cube and clean the compression plate surface for next test.

21. Continue the above procedure for the remaining cubes.

22. Note down the crushing load for each cube separately.

Compressive strength of 1:3 mortars ASTM C-109:

Cured or 3-Days:

Compressive strength = 3300 psi

Cured for 7-Days:

Compressive strength = 5900 psi

RESULTS & CALCULATIONS

S.No Crushing Load Area in2 Compressive Strength

1

2

3

Average Strength = ________________

EXPERIMENT No # 12

To Determine the Compacting Factor of Concrete

OBJECTIVE:

To determine the compacting factor or the degree of compaction, this gives us an indication of

the workability of fresh concrete materials.


The principle of compacting factor is determining the degree of compaction achieved by a

standard amount of work done by allowing the concrete to fall through a standard height. The

degree of compaction is measured by the density ratio, ( The ratio of density actually achieved in

the test to density of same concrete fully compacted) This test primarily for use in the laboratory

but it can also be used in the field, useful for concrete mixes of low, medium and high workable.

APPARATUS:

Compacting factor apparatus: Upper hopper with a dimension (Top: 254 mm, bottom: 127 mm

and height: 279 mm), lower hopper with a dimension (Top: 229, Bottom: 127, and height: 229

mm) and cylinder (with dia. 152 and height 305 mm) connected, the total height measuring from

the base of upper hopper to the base of cylinder about 1 m.

Procedure

1. Clean and moisten the internal sides of the upper and lower hoppers using dampen cloth.

2. Place the sample of prepared fresh concrete in the upper hopper; so that the sliding door

closes.

3. Open the top slide door, so that the concrete falls into the lower hopper.

4. Open the slide door of the lower hopper, so that the concrete is allowed to fall into the

cylinder. Remove the excess concrete above the top level of the cylinder, the outside is

wiped clean. Weigh the concrete in the cylinder that is partially compacted let be W1.

5. Empty the cylinder and fill it with the concrete from the same sample in 3 layers

approximately of equal volumes.

6. Each layer heavily rammed or vibrated so as to obtain full compaction.

7. Level the top surface of the fully compacted concrete with the top of the cylinder, and

weigh it, let to be W2.

Figure1: Compaction Factor Test

Results &Conclusions

𝑇ℎ𝑒𝐶𝑜𝑚𝑝𝑎𝑐𝑡𝑖𝑛𝑔𝐹𝑎𝑐𝑡𝑜𝑟 = 𝑊𝑒𝑖𝑔ℎ𝑡𝑜𝑓𝑝𝑎𝑟𝑡𝑖𝑎𝑙𝑙𝑦𝑐𝑜𝑚𝑝𝑎𝑐𝑡𝑒𝑑𝐶𝑜𝑛𝑐𝑟𝑒𝑡 (𝑤1)

𝑊𝑒𝑖𝑔ℎ𝑡𝑜𝑓𝐹𝑢𝑙𝑙𝑦𝐶𝑜𝑚𝑝𝑎𝑐𝑡𝑒𝑑𝐶𝑜𝑛𝑐𝑟𝑒𝑡𝑒 (𝑤2)

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