Darshan Institute of Engineering & Technology...IS: 4031 (Part 1) -1996 Introduction: The fineness of cement has an important bearing on the rate of hydration and hence on the rate

Laboratory Manual

2140608 – Concrete Technology

Darshan Institute of

Engineering & Technology

Concrete Technology Lab Manual

Degree Civil Engineering Semester – IV

Name of Student:- Enrollment No.:- Batch:- Roll No.:-

Laboratory Manual


CONTENT

Sr. No.

Description Page No.

Date Sign

Cement

1 Fineness of Cement (By Dry Sieving) 1 2 Standard Consistency of Cement 2

3 Initial and Final setting time of Cement

4

4 Soundness of cement 6 5 Compressive strength of cement 8 Aggregates

6 Particle size distribution of FA 10

7 Specific gravity, moisture content and water absorption of FA and CA

13

8 Flakiness index and Elongation index 17

9 Aggregate Impact value 20 10 Aggregate Crushing value 23

11 Aggregate Abrasion value 25 Concrete (Fresh)

12 Slump test 28 13 Compacting factor test 29

Concrete (Hardened)

14 Compressive Strength Test 34

15 Tensile strength test or Split cylinder test

36

16 Flexural Strength test 38

Civil Engineering Department | 1. Fineness of Cement (By Dry Sieving) 1


Laboratory Manual

1. Fineness of Cement (By Dry

Sieving) Object:

This method of test covers the procedures for determining the Fineness of cement by dry sieving as

represented by the mass of the residue left on a standard 90-micron I.S. Sieve.

Reference: IS: 4031 (Part 1) -1996

Introduction: The fineness of cement has an important bearing on the rate of hydration and hence on the rate of gain

of strength and also on the rate of evolution of heat. Finer cement offers a greater surface area of

hydration and hence the faster and greater the development of strength. Increase in fineness of cement

is also found to increase the drying shrinkage of concrete.

Apparatus: The apparatus required for the test is as follows:

I. 90-micron I.S. Sieve

II. Pan with cover

III. Balance etc.

Procedure: 1. Weigh accurately 100 g of cement and place it on a standard 90 micron IS sieve.

2. Break down any air-set lumps in the cement sample with fingers.

3. Continuously sieve the sample giving circular and vertical motion for a period of 15 minutes.

4. Weigh the residue left on the sieve. As per IS code the percentage residue should not exceed

10% for OPC and 5% for RHC.

Precautions: Air set lumps in the cement sample are to be crushed using fingers and not to be pressed with the sieve.

Sieving shall be done holding the sieve in both hands and with gentle wrist motion.

Observations:

Sr. No. Weight of sample taken (gm) Weight of residue

(gm) Fineness %

Result:

Average of fineness % = Weight of Residue

𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑆𝑎𝑚𝑝𝑙𝑒 X 100 = ………………..

Faculty Signature

Civil Engineering Department | 2. Standard Consistency of Cement 2


Laboratory Manual

2. Standard Consistency of Cement

Object:

This standard covers the procedure for determining the quantity of water required to produce a cement

paste of standard consistency.

Reference: IS: 4031 (Part 4) – 1988

IS : 5513-1976

Introduction: The standard consistency of a cement paste is defined as that consistency which will permit the Vicat

Plunger having 10mm diameter to penetrate to a point 5 to 7 mm from the bottom of the Vicat mould.

For finding out initial setting time, final setting time, soundness of cement and compressive strength of

cement, it is necessary to fix the quantity of water to be mixed in cement in each case. This experiment is

intended to find out the quantity of water to be mixed for a given cement to give a cement paste of

normal consistency and can be done with the help of Vicat Apparatus.

Apparatus:

I. Vicat Apparatus

II. Balance

III. Beaker

IV. Gauging trowel

V. Stop watch etc.

Procedure: 1. Prepare a paste of weighed quantity of cement with a weighed quantity of potable or distilled water,

starting with 26% water of 400g of cement.

2. Take care that the time of gauging is not less than 3 minutes, not more than 5 minutes and the gauging

shall be completed before setting occurs.

3. The gauging time shall be counted from the time of adding the water to the dry cement until

commencing to fill the mould.

4. Fill the Vicat mould with this paste, the mould resting upon a non-porous plate.

5. After completely filling the mould, trim off the surface of the paste, making it in level with the top of

the mould.

6. Place the test block with the mould, together with the non-porous resting plate, under the rod bearing

the plunger (10mm diameter), lower the plunger gently to touch the surface of the test block and

quickly release, allowing it to penetrate into the paste.

7. This operation shall be carried out immediately after filling the mould.

8. Prepare trial pastes with varying percentages of water and test as described above until the amount of

water necessary for making the standard consistency as defined above is obtained.

9. Express the amount of water as a percentage by weight of the dry cement.

Civil Engineering Department | 2. Standard Consistency of Cement 3


Laboratory Manual

Precautions: Clean appliances shall be used for gauging. In filling the mould the operator hands and the blade of the gauging trowel shall alone be used. The temperature of cement, water and that of test room, at the time when the above operations are being performed, shall be 270+ 20 C and humidity 65+5%. For each repetition of the experiment fresh cement is to be taken.

OBSERVATIONS:

Sr. No. Wt. of Cement % of Water (P) Wt. of Water Penetration

1.

2.

3.

4.

5.

Result: Standard consistency (P) for the given sample of cement is ________ %.

Faculty Signature

Civil Engineering Department | 3. Initial and Final Setting Times of Cement 4


Laboratory Manual

3. Initial and Final Setting Times of

Cement Object:

This standard covers the procedure for determining the Initial & Final Setting Times of cement

Reference: 4031 (Part 5) -1988

IS : 5513-1976

Introduction:

In actual construction dealing with cement, mortar or concrete, certain time is required for mixing, transporting and placing. During this time cement paste, mortar, or concrete should be in plastic condition. The time interval for which the cement products remain in plastic condition is known as the setting time. Initial setting time is regarded as the time elapsed between the moments that the water is added to the cement to the time that the paste starts losing its plasticity. The final setting time is the time elapsed between the moment the water is added to the cement, and the time when the paste has completely lost its plasticity and has attained sufficient firmness to resist certain pressure. The constituents and fineness of cement is maintained in such a way that the concrete remains in plastic condition for certain minimum time. Once the concrete is placed in the final position, compacted and finished it should lose its plasticity in the earliest possible time so that it is least vulnerable to damages from external destructive agencies. Initial setting time should not be less than 30 min., Final setting time should not be more than 600min. (10 hours).

Apparatus: I. Vicat Apparatus

II. Balance

III. Beaker

IV. Gauging trowel

V. Stop watch etc.

Procedure: 1. Prepare a neat cement paste by gauging 400 grams of cement with 0.85 times the water required to

give a paste of standard consistency (0.85 x P).

2. Potable or distilled water shall be used in preparing the paste.

3. The paste shall be gauged in the manner and under the conditions prescribed in determination of

consistency of standard cement paste.

4. Start a stop-watch at the instant when water is added to the cement and note time when water is

added

5. Fill the mould with the cement paste gauged as above the mould resting on a nonporous plate.

6. Fill the mould completely and smooth surface of the paste making it level with the top of the mould.

The cement block thus prepared in the mould is the test block.

Civil Engineering Department | 3. Initial and Final Setting Times of Cement 5


Laboratory Manual

Determination of Initial Setting Time

1. Place the test blocks confined in the mould and rest it on the non-porous plate, under the rod

bearing initial setting needle, lower the needle gently in contact with the surface of the test block

and quickly release, allowing it to penetrate into the test block.

2. In the beginning, the needle will completely pierce the test block.

3. Repeat this procedure until the needle, when brought in contact with the test block and released

as described above, fails to pierce the block to a point 5 to 7mm measured from the bottom of the

mould shall be the initial setting time.

Determination of Final Setting Time

1. Replace the needle of the Vicat apparatus by the needle with an annular attachment the cement

shall be considered as finally set when, upon applying the needle gently to the surface of the test

block, the needle makes an impression there on, while the attachment fails to do so.

2. The period elapsed between the time when water is added to the cement and the time at which

the needle makes an impression on the surface of test block while the attachment fails to do so

shall be the final setting time.

Precautions: Clean appliances shall be used for gauging. All the apparatus shall be free from vibration during the test.

The temperature of water and that of the test room, at the time of gauging shall be 270 C + 20 C and

humidity 65+5% Care shall be taken to keep the needle straight.

Observations:

Time when water is added

(A)

Time for Initial set

(B)

Time for Final set

(C)

Result:

Initial setting time for the given sample of cement = Difference of (A) & (B) = _______

Final setting time for the given sample of cement = Difference of (A) & (C) = ________

Faculty Signature

Civil Engineering Department | 4. Soundness of Cement 6


Laboratory Manual

4. Soundness of Cement Object: This standard covers the procedures for determining the soundness of cement.


IS : 5514-1969

Introduction: It is essential that the cement concrete shall not undergo appreciable change in volume after setting. This

is ensured by limiting the quantities of free lime, magnesia and sulphats in cement which are the causes

of the change in volume known as unsoundness. Unsoundness in cement does not come to surface for a

considerable period of time. This test is designed to accelerate the slaking process by the application of

heat and discovering the defects in a short time. Unsoundness produces cracks, distortion and

disintegration there by giving passage to water and atmospheric gases which may have injurious effects

on concrete and reinforcement.

The apparatus for conducting the test consists of small split cylinder of spring brass or other suitable

metal of 0.5mm thickness forming a mould 30 mm internal diameter and 30mm height. On either side of

the split mould are attached to indicators with pointed ends, the distance from these ends to the center

of the cylinder being 165 mm.

Apparatus: I. Le-Chatelier apparatus

II. Balance

III. Water bath

IV. Beaker etc.

Procedure:

1. Place the lightly oiled mould on a lightly oiled glass sheet and fill it with cement paste formed by

gauging cement with 0.78 times the water required to give a paste of standard consistency.

2. The paste shall be gauged in the manner and under the conditions prescribed in determination of

consistency of standard cement paste, taking care to keep the edges of the mould gently together.

3. Measure the distance separating the indicator points.

4. While this operation is being performed cover the mould with another piece of glass sheet, place a

small weight on this covering glass sheet and immediately submerge the whole assembly in water

at a temperature of 270+ 20C and keep there for 24 hours.

5. After then put mould in water bath Bring the water to boiling, with the mould kept submerged, in

25 to 30 minutes, and keep it boiling for three hours.

6. Remove the mould from the water allow it to cool and measure the distance between the

indicator points. The difference between these two measurements represents the expansion of

the cement.

Civil Engineering Department | 4. Soundness of Cement 7


Laboratory Manual

7. Measure the distance separating the indicator points.

8. For good quality cement this expansion should not be more than 10mm.

Fig. Le- chatelier's apparatus

Observations: Time when water is added = …………………

Sr. No. Initial distance

(mm) Final distance

(mm) Expansion

(mm)

Result: Average Expansion (mm) =_______________

Faculty Signature

Civil Engineering Department | 5. Compressive Strength of Cement 8


Laboratory Manual

5. Compressive Strength of Cement Object: This method of test covers the procedures for determining the Strength of cement as represented by

compressive strength tests on mortar cubes compacted by means of a standard vibration machine.

Reference:

IS: 4031 (Part 6) -1988

IS : 10080-1982

IS : 650-1966

IS: 269-1976

Introduction: The compressive strength of cement mortars is determined in order to verify whether the cement

conforms to IS specifications and whether it will be able to develop the required compressive strength of

concrete. The average compressive strength of at least three mortar cubes (area of the face 50 cm2 )

composed of one part of cement and three parts of standard stand should satisfy IS code specifications.

Apparatus: I. Cubes having size of 7.06 X 7.06 X 7.06 cm

II. Balance

III. Baby vibrator

IV. Water bath

V. Gauging Trowel etc.

Procedure: 5. The Standard or Natural sand to be used in the test.

6. Take 600 grams of Standard or Natural sand, 200 grams of cement (i.e. ratio of cement to sand is

1:3) in a non-porous enamel tray & mix them with a trowel for 1minute.

7. Add water of quantity (P/4) + 3 % (for Standard sand) or (P/4) + 3.5 % (for Natural sand) of

combined weight of cement & sand and mix the three ingredients thoroughly until the mixture is

of uniform colour. The time of mixing should not be less than 3 minutes and not more than 4

minutes.

8. Immediately after mixing, the mortar is filled into a cube mould.

9. The area of the face of the cube will be equal to 50cm2.

10. Compact the mortar either by hand compaction in a standard specified manner or on the

vibrating equipment (12000 RPM).

11. Keep the compacted cube in the mould at a temperature of 270+ 20C & at least 90% relative

humidity for 24hours.

12. Where the facility of standard temperature & humidity room is not available, the cube may be

kept under wet gunny bag to stimulate 90% relative humidity.

13. After 24hours, remove the cubes from the mould & immerse in clean fresh water until taken out

for curing.

14. Three cubes for each are tested for compressive strength at the interval of 3, 7 & 28 days.

Civil Engineering Department | 5. Compressive Strength of Cement 9


Laboratory Manual

Testing:

1. Test three cubes for compressive strength at the periods mentioned under the relevant

specification for different hydraulic cements, the periods being reckoned from the completion of

vibration.

2. The compressive strength shall be the average of the strengths of three cubes for each period of

curing.

3. The cubes shall be tested on their sides without any packing between the cube and the steel

plates of the testing machine.

4. One of the plates shall be carried base and shall be self-adjusting and the load shall be

steadily and uniformly applied starting from zero at a rate of 350 Kgs/Cm2/ min.

5. The cubes are tested at the following period Ordinary portland cement 3, 7 and 28 days. Rapid

hardening portland cement 1 and 3 days. Low heat portland cement 3 and 7 days etc.

Precautions: Inside of the cube moulds should be oiled.

Materials: Cement (gm) Sand (gm) Water (ml)

Observation:

Sr. No.

Days

Dimension Area (mm2)

(A) Load taken (N)

(B)

Compressive Strength (B)/(A)

(N/mm2)

Average Compressive

Strength (N/mm2)

Length (mm)

Width (mm)

Result: The average compressive strength of the given cement,

At 3 days N/mm2 =

At 7 days N/mm2 =

At 28 days N/mm2 =

Faculty Signature

Civil Engineering Department | 6. Particle size distribution of FA 10

Laboratory Manual


6. Particle size distribution of FA

Object: To determine fineness modulus of fine aggregate and classifications based on IS: 383-1970


IS:460-1962

IS: 383-2016

Introduction: This is the name given to the operation of dividing a sample of aggregate into various fractions each consisting

of particles of the same size. The sieve analysis is conducted to determine the particle size distribution in a

sample of aggregate, which we call gradation. Many a time, fine aggregates are designated as fine sand,

medium sand and coarse sand. These classifications do not give any precise meaning. What the supplier terms

as fine sand may be really medium or even coarse sand.

The following limits may be taken as guidance:

Fine sand: F.M. : 2.2 - 2.6

Medium sand: F.M. : 2.6 - 2.9

Coarse sand: F.M. : 2.9 - 3.2

(Note: Sand having a fineness modulus more than 3.2 will be unsuitable for making satisfactory concrete.)

Test sample: The weight of the sample available shall not be less than the weight given in the table below. The sample for

sieving shall be prepared from the larger sample either by quartering or by means of sample divider.

Maximum Size present in Substantial proportions

(mm)

Minimum weight of sample required for

quartering (Kg)

20 25

10 6

6.3 3


Laboratory Manual


Minimum weight of sample required for Sieve analysis after Quartering shall be as follows.

Maximum Size present in Substantial

proportions (mm)

Minimum weight of sample required for Sieve

analysis (Kg)

20 2.0

10 0.5

4.75 0.2

Apparatus: I. Sieves (Conforming to IS:460-1962) of size 40mm, 20mm, 12.5mm, 10mm, 4.75mm, 2.36mm,

1.18mm, 600 micron, 300 micron, 150 micron and pan.

II. Balance

III. Sieve Shaker

Procedure: 1. The sample shall be brought to an air-dry condition before weighing and sieving. The air-dry sample

shall be weighed and sieved successively on the appropriate sieves starting with the largest. Care shall

be taken to ensure that the sieves are clean before use.

2. The shaking shall be done with a varied motion, backward and forwards, left to right, circular

clockwise and anti-clockwise, and with frequent jarring, so that the material is kept moving over the

sieve surface in frequently changing directions.

3. Material shall not be forced through the sieve by hand pressure. Lumps of fine material, if present,

may be broken by gentle pressure with fingers against the side of the sieve.

4. Light brushing with a fine camel hair brush may be used on the 150-micron IS Sieves to prevent

aggregation of powder and blinding of apertures.

Observation: Weight of sample taken:- __________ gm

I S Seive

Weight

Retained

(gm)

Cumulative Wt.

Retained (gm)

Cumulative Wt.

Retained % % Passing

Zone

(as per

IS 383 : 2016)

10 mm

4.75 mm

2.36mm

1.18mm

600 micron

300 micron

150 micron

Pan

F.M. = 𝑇𝑜𝑡𝑎𝑙 𝑐𝑢𝑚𝑢𝑙𝑎𝑡𝑖𝑣𝑒 𝑤𝑡. 𝑟𝑒𝑡𝑎𝑖𝑛𝑒𝑑 (%)

100


Laboratory Manual


Reference:

IS 383:2016 table no.4 grading limits of fine aggregates

I S Seive

Designation

Percentage Passing by weight

Grading Zone I Grading Zone II Grading Zone III Grading Zone IV

10 mm 100 100 100 100

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

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

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

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

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

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

Faculty Signature

Civil Engineering Department | 7. Specific Gravity, Moisture content and Water Absorption for Fine and Coarse Aggregate

13

Laboratory Manual


7. Specific Gravity, Moisture content

and Water Absorption for Fine and

Coarse Aggregate Object: To determine specific gravity, moisture content and water absorption of a given sample of fine and

course aggregate.

Reference: IS : 2386 ( Part III ) – 1963

Apparatus: I. Balance of capacity not less than 3 kg with accuracy of 0.5 gm

II. Oven to maintain a temperature of 100 to 110oC

III. Pycnometer of about 1 L capacity

IV. Tray for drying the sample etc.

Procedure: Part I Coarse Aggregate

(i) The sample shall be screened on a 10mm IS Sieve, thoroughly washed to remove fine dust and immerse in distilled water at temperature 22° to 32° C for 24 ± 0.5 hr. (ii) After immersion and again at the end of soaking period, air entrapped or bubble on the surface aggregate shall be removed by gentle agitation.

(iii) The vessel shall be overfilled by adding distilled water and the plane ground glass disc slid over the mouth so as to ensure that no air is trapped in the vessel. The vessel shall be dried on the outside and weighted (A).

(iv) The vessel shall be emptied and the aggregate allowed to drain refill the vessel with distilled water slide the glass disc in position as before .The vessel shall be dried on the outside and weighted (B).

(v) The difference in the temperature of water in the vessel during the first & second weighting shall not exceed 2° C. (vi) The aggregate shall be placed on dry cloth and gently surface dried with cloth, transferring it to second dry

cloth, when the first will remove no further moisture, left exposed to atmosphere away from direct sunlight or

any other source of heat not less than 10 min or until it appear to complete surface dry, The aggregate shall

then be Weighted (C).


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Laboratory Manual


(vii) The aggregate shall be placed in the oven in shallow tray, at a temperature of 100° to 110° C for 24 ± 0.5 hr.

It shall than be cooled in air tight container & Weight(D).

Now calculate the Specific gravity and Water absorption from the formulae given below:

𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑔𝑟𝑎𝑣𝑖𝑡𝑦 =𝐷

𝐶 − (𝐴 − 𝐵)

𝑊𝑎𝑡𝑒𝑟 𝑎𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 =(𝐶 − 𝐷)

𝐷 𝑋 100

Part II Fine Aggregate

(i) 500 gm of sample finer than 4.75mm shall be placed in the tray and covered with distilled water at a temperature of 22° to 32° C, after immersed air entrapped in a bubble on the surface of the aggregate shall be removed by gentle agitation with a rod. The sample shall remain immerse for 24 ± 0.5hr. (ii)The water shall then be carefully drained from the sample, by decantation through a filter paper, any material retained being returned to the sample. The aggregate including any solid matter retained on the filter paper shall be exposed to a gentle current retained on evaporate surface moisture and shall be stirred at frequent intervals to ensure that this stage is not passed. The saturated and surface dry sample shall be weighted(A)

(iii)The aggregate shall then be placed in the pycnometer which shall be filled with distilled water. Any trapped air shall be eliminate by rotating the pycnometer on its side, the hole in the apex of cone being covered with a finger. The pycnometer shall be dried on the outside and weighted(B)


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Laboratory Manual


(iv)The pycnometer shall be refilled with distilled water to the same level as before, dried on the outside and weighted(C) (v)the sample shall be placed in the oven in the tray at a temperature of 100° to 110° C for 24 ± 0.5hr, during which period and then it cooled in air tight container and weighted(D). Now calculate the Specific gravity and Water absorption from the formulae given below:

𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑔𝑟𝑎𝑣𝑖𝑡𝑦 =𝐷

𝐴 − (𝐵 − 𝐶)

𝑊𝑎𝑡𝑒𝑟 𝑎𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 =(𝐴 − 𝐷)

𝐷 𝑋 100

Part III MOISTURE CONTENT OF AGGREGATE

(i) 500 gm of sample finer than 4.75mm shall be placed in the tray(A). (ii) Sample should be kept in oven for 24 ± 0.5hr at temperature of 100° to 110 °C. (iii)Sample should be dry surface with the help of cotton and then weight once again(B).

Now calculate moisture content of aggregate from the formulae given below:

𝑀𝑜𝑖𝑠𝑡𝑢𝑟𝑒 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 =(𝐴−𝐵 )

𝐵 X 100

Sr no.

FA CA

1 Empty Weight of wire bucket W1

Empty Weight of

wire bucket W1

2 W1 + weight of dry aggregate W2

W1 + weight of dry

aggregate W2

3 W2 + weight of water W3 W2 + weight of water W3

4 W1 + weight of water W4 W1 + weight of water W4

𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑔𝑟𝑎𝑣𝑖𝑡𝑦 = 𝑊2 − 𝑊1

(𝑊2 − 𝑊1) − (𝑊3 − 𝑊4)


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Laboratory Manual


1 weight of aggregate W1 2 Dry Weight of aggregate W2

𝑀𝑜𝑖𝑠𝑡𝑢𝑟𝑒 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 = 𝑊1 − 𝑊2

𝑊2 𝑋 100

Result:

I. The Moisture Content of a given sample of fine aggregate is found to be ……………%

II. The Water Absorption of a given sample of fine aggregate is found to be ……………%

III. The Specific Gravity of a given sample of fine aggregate is found to be …………..

IV. The Moisture Content of a given sample of Coarse aggregate is found to be ……………%

V. The Water Absorption of a given sample of Course aggregate is found to be ………….. %

VI. The Specific Gravity of a given sample of Course aggregate is found to be …………..

Faculty Signature

Civil Engineering Department | 8. Flakiness Index and Elongation Index 17

Laboratory Manual


8. Flakiness Index and Elongation

Index Object: To determine the value of Flakiness Index and Elongation Index of Coarse aggregates.

Reference : IS: 2386 (Part 1) -1963]

IS: 383-2016

IS : 460-1962

Introduction: Particle shape and surface texture influence the properties of freshly mixed concrete more than the properties

of hardened concrete. Rough-textured, angular, and elongated particles require more water to produce

workable concrete than smooth, rounded compact aggregate. Consequently, the cement content must also be

increased to maintain the water-cement ratio. Generally, flat and elongated particles are avoided or are

limited to about 15 % by weight of the total aggregate.

Apparatus:

The metal gauge shall be of the pattern shown in Fig. 10.1, Balance, Gauging Trowel, Stop Watch,

etc.

Fig. Thickness gauge


Laboratory Manual


Fig. Length Gauges

Procedure:

Flakiness Index 1) The sample shall be sieved through the sieves specified in Table

Dimension of Thickness and Length Gauges

(Clause 4.2, 4.4.1, 4.4.2, 5.2 and 5.4.1)

Size of Aggregate Thickness Gauge *

(mm)

Length Gauge ↑

(mm) Passing Through

IS Sieve

Retained on

IS Sieve

(1) (2) (3) (4)

63 mm 50 mm 33.90 --

50 mm 40 mm 27.00 81.0

40 mm 31.5 mm 21.5 64.4

31.5 mm 25 mm 16.95 --

25 mm 20 mm 13.50 40.5

20 mm 16 mm 10.80 32.4

16 mm 12.5 mm 8.55 25.6

12.5 mm 10 mm 6.75 20.2

10 mm 6.3 mm 4.89 14.7

* This dimension is equal to 0.6 times the mean sieve size

↑ This dimension is equal to 1.8 times the mean sieve size

1. 200 pieces shall be taken from each fraction and the flaky samples shall be weighed to an accuracy of

0.1 % of the test sample

2. Calculate the flakiness index = 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑓𝑙𝑎𝑘𝑦 𝑎𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 (𝑝𝑎𝑠𝑠𝑖𝑛𝑔)

𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡𝑜𝑡𝑎𝑙 𝑎𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 𝑋 100

Elongation Index Elongation Index of an aggregate is the percentage by weight of particles whose greatest dimension (length) is

greater than 1.8 times their mean dimension. Remaining aggregate pieces of sample shall be taken from each

fraction and the elongated samples shall be separated from the total sample taken.


Laboratory Manual


Calculate the Elongation Index = 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑒𝑙𝑜𝑛𝑔𝑎𝑡𝑒𝑑 𝑎𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 (𝑟𝑒𝑡𝑎𝑖𝑛𝑒𝑑)

𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑎𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 (𝑎𝑓𝑡𝑒𝑟 𝑟𝑒𝑚𝑜𝑣𝑖𝑛𝑔 𝑓𝑙𝑎𝑘𝑦 𝑎𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒) x 100

Observation:

The flakiness index of a given sample of Course aggregate is …………………. %

The elongation index of a given sample of Course aggregate is ……………….. %

Faculty Signature

Sr

No

Sieve

Size(mm)

Weight of

Sample

W1

Weight of

Sample

Passing from

Thickness

Gauge

W2

Weight of

Sample

Retain

from

Thickness

Gauge

W3

Weight of

Sample

Retain

from

Length

Gauge

W4

FI (%)

= 𝑾𝟐

𝑾𝟏 𝑿 𝟏𝟎𝟎

EI (%)

=𝑾𝟒

𝑾𝟑 𝑿 𝟏𝟎𝟎

Civil Engineering Department | 9. Impact Value Test 20

Laboratory Manual


9. Impact Value Test Object: This method of test covers the procedure for determining the aggregate impact value of coarse aggregate.


IS: 383-1970

Introduction: The aggregate impact value gives a relative measure of the resistance of an aggregate to sudden shock or

impact, which in some aggregates differs from its resistance to a slow compressive load.

Apparatus:

An impact testing machine of the general form shown in Fig. 4 and complying with the following:

I. Total weight not more than 60kg or less than 45kg.

II. The machine shall have a metal base weighing between 22 and 30 kg with a plane lower surface of not

less than 30 cm diameter, and shall be supported on a level and plane concrete or stone block or floor

at least 45 cm thick. The machine shall be prevented from rocking either by fixing it to the block or

floor or by supporting it on a level and plane metal plate cast into the surface of the block or floor.

III. A cylindrical steel cup of internal dimensions: Diameter 102 mm, Depth 50 mm and not less than 6.3

mm thick. A cylindrical metal measure, tarred to the nearest, gram of sufficient rigidity to retain its

form under rough usage, and of 75mm diameter and 50mm depth.

IV. A metal cup or hammer weighing 13.5 to 14.0 kg, the lower end of which shall be cylindrical in shape,

100.0 mm in diameter and 5 cm long, with a 2 mm chamfer at the lower edge, and case-hardened. The

hammer shall slide freely between vertical guides so arranged that the lower (cylindrical) part of the

hammer is above and concentric with the cup.

V. Means for raising the hammer and allowing it to fall freely between the vertical guides from a height

of 380.0 mm on to the test sample in the cup, and means for adjusting the height of fall within 5 mm.

VI. Sieves-The IS Sieves of sizes 12.5, 10 and 2.36 mm, Tamping Rod 23 cm long and 1 cm in dia., balance

of capacity not less than 500 g, Oven etc.


Laboratory Manual


Fig. : Aggregate Impact Testing Machine

Procedure `:

1. The test sample shall consist of aggregate the whole of which passes a 12.5 mm IS Sieve and is

retained on a 10 mm IS Sieve. The aggregate comprising the test sample shall be dried in an oven for

a period of four hours at a temperature of 100° to 110°C and cooled.

2. The measure shall be filled about one-third full with the aggregate and tamped with 25 strokes of the

rounded end of the tamping rod. The net weight of aggregate in the measure shall be determined the

weight of sample in gram (Weight A).

3. The impact machine shall rest without wedging or packing upon the level plate, block or floor, so that

it is rigid and the hammer guide columns are vertical.

4. The cup shall be fixed firmly in position on the base of the machine and the whole of the test sample

placed in it and compacted by a single tamping of 25 strokes of the tamping rod.

5. The hammer shall be raised until its lower face is 380 mm above the upper surface of the aggregate

in the cup, and allowed to fall freely on to the aggregate. The test sample shall be subjected to a total

of 15 such blows each being delivered at an interval of not less than one second.

6. The crushed aggregate shall then be removed from the cup and the whole of it sieved on the 2.36

mm IS Sieve until no further significant amount passes in one minute. The fraction passing the sieve

shall be weighed to an accuracy of 0.1 g (Weight B).

7. The fraction retained on the sieve shall also be weighed (Weight C) and, if the total weight (C+B) is

less than the initial weight (Weight A) by more than one gram, the result shall be discarded and a

fresh test made. Two tests shall be made.

Calculation:

The ratio of the weight of fines formed to the total sample weight in each test shall he expressed as a

percentage, the result being recorded to the first decimal place:

Aggregate Impact Value X 100


Laboratory Manual


A weight in gm of saturated surface - dry sample=______gm

B weight in gm of fraction passing through 2.36 mm IS Sieve=_______gm

C=Weight in gm of fraction retained on 2.36 mm IS Sieve=______gm

D=Difference due to loss of Material=A-(B+C)=______gm (Should be <1gm)

Result:

The aggregate Impact value of given sample of coarse aggregate is ……….. %

The aggregate impact value should not be more than 45 per cent for aggregate used for concrete other than

for wearing surfaces, and 30 per cent for concrete used for wearing surfaces such a runways, roads and air

field pavements.

Faculty Signature

Civil Engineering Department | 10. Determination of Aggregate Crushing value 23

Laboratory Manual


10. Determination of Aggregate

Crushing value Objective: This method of test covers the procedure for determining the aggregate crushing value of coarse aggregate.

Reference: IS : 2386 ( Part IV) – 1963

IS: 383-1970

Apparatus: A 15-cm diameter open-ended steel cylinder, with plunger and base-plate, of the general form and dimensions

shown in Fig. ,A straight metal tamping rod, A balance of capacity 3 kg, readable and accurate to one gram, IS

Sieves of sizes 12.5, 10 and 2.36 mm, For measuring the sample, cylindrical metal measure of sufficient rigidity

to retain its form under rough usage and of the following internal dimensions: Diameter 11.5 cm and Height

18.0 cm

Fig.: Aggregate crushing value apparatus

Civil Engineering Department | 24

Laboratory Manual


Procedure:

1. The material for the standard test shall consist of aggregate passing a 12.5 mm IS Sieve and retained

on a 10 mm IS Sieve, and shall be thoroughly separated on these sieves before testing.

2. The aggregate shall be tested in a surface-dry condition. If dried by heating, the period of drying shall

not exceed four hours, the temperature shall be 100 to 110°C and the aggregate shall be cooled to 33

room temperature before testing.

3. The appropriate quantity may be found conveniently by filling the cylindrical measure in three layers

of approximately equal depth, each layer being tamped 25 times with the rounded end of the

tamping rod and finally leveled off, using the tamping rod as a straight-edge.

4. The weight of material comprising the test sample shall be determined (Weight A) and the same

weight of sample shall be taken for the repeat test.

5. The apparatus, with the test sample and plunger in position, shall then be placed between the

platens of the testing machine and loaded at as uniform a rate as possible so that the total load is

reached in 10 minutes. The total load shall be 400 kN.

6. The load shall be released and the whole of the material removed from the cylinder and sieved on a

2.36 mm IS Sieve for the standard test. The fraction passing the sieve shall be weighed (Weight B).

Calculation:

The ratio of the weight of fines formed to the total sample weight in each test shall be expressed as a

percentage, the result being recorded to the first decimal place:

Weight of saturated surface dry aggregate in gm. (A)

Weight of aggregate passing from 2.36mm IS Seive in gm. (B)

Aggregate Abrasion Value = (B/A) X 100

Aggregate Crushing Value X 100

A weight in gm of surface - dry sample,

B weight in gm of fraction passing through appropriate sieves

Conclusion / Result :

The aggregate crushing value of given sample of coarse aggregate is ……….. %

The aggregate crushing value should not be more than 45 per cent for aggregate used for concrete other than

for wearing surfaces, and 30% for concrete used for wearing surfaces such a runways, roads and air field

pavements.

Faculty Signature

Civil Engineering Department | 11. Aggregate Abrasion Value 25

Laboratory Manual


11. Aggregate Abrasion Value

Object: This method of test methods of determining the abrasion value of coarse aggregate by the use of Los Angeles

machine.

Reference: IS: 2386 (Part 4) -1996]

IS: 383-1970

Introduction:

Abrasive Charge-The abrasive charge shall consist of cast iron spheres or steel spheres approximately 48 mm

in. diameter and each weight between 390 and 445 g.

Sr No Grading Number of Spheres Weight of charge (gm)

1 A 12 5000 ± 25

2 B 11 4584 ± 20

3 C 8 3330 ± 20

4 D 6 2500 ± 15

5 E 12 5000 ± 25

6 F 12 5000 ± 25

7 G 12 5000 ± 25

Table: Specified abrasive charge The test sample consist of clean aggregate which has been dried in an oven at 105°C to 110°C and it should

conform to one of the grading shown in Table.

Sieve Size Weight in gm. of Test Sample for Grade

Passing

mm

Retained on

mm

A B C D E F G

80 63 -- -- -- -- 2500 -- --

63 50 -- -- -- -- 2500 -- --

50 40 -- -- -- -- 5000 5000 --

40 25 1250 -- -- -- -- 5000 5000

25 20 1250 -- -- -- -- -- 5000

20 12.5 1250 2500 -- -- -- -- --

12.5 10 1250 2500 -- -- -- -- --

10 6.3 -- -- 2500 -- -- -- --

6.3 4.75 -- -- 2500 -- -- -- --

4.75 2.36 -- -- -- 5000 -- -- --

Table: Grading of test samples


Laboratory Manual


Apparatus: Los Angeles machine - The Los Angeles abrasion testing machine shall consist of a hollow steel cylinder, closed

at both ends, having an inside diameter of 700 mm and an inside length of 500 mm. The cylinder shall be

mounted on stub shafts attached to the ends of the cylinders but not entering it, and shall be mounted in

such, a manner that it may be rotated about its axis in a horizontal position. An opening in the 37 cylinder shall

be provided for the introduction of the test sample. A removable steel shelf, projecting radially 88 mm into

the cylinder and extending its full length, shall be mounted along one element of the interior surface of the

cylinder. The shelf shall be of such thickness and so mounted, by bolts or other approved means, as to be firm

and rigid. The 1.70 mm IS Sieve.

Fig.: Loss Angeles Abrasion Testing Machine


Laboratory Manual


Procedure:

1. The test sample shall consist of clean aggregate which has been dried in an oven at 105° to 110°C to

substantially constant weight and shall conform to one of the grading shown in Table 3.22. The

grading used shall be those most nearly representing the aggregate furnished for the work.

2. The test sample and the abrasive charge shall be placed in the Los Angeles abrasion testing machine

and the machine rotated at a speed of 20 to 33 rev/min. For grading A, B, C and D, the machine shall

be rotated for 500 revolutions; for grading E, F and G, it shall be rotated for 1000 revolutions.

3. The machine shall be so driven and so counter-balanced as to maintain a substantially uniform

peripheral speed. If an angle is used as the shelf, the machine shall be rotated in such a direction that

the charge is caught on the outside surface of the angle.

4. At the completion of the test, the material shall be discharged from the machine and a preliminary

separation of the sample made on a sieve coarser than the 1.70 mm IS Sieve.

5. The material coarser than the 1.70 mm IS Sieve shall be washed dried in an oven at 105 to 110°C to a

substantially constant weight, and accurately weighed to the nearest gram.

Calculation :

The difference between the original weight and the final weight of the test sample is expressed as a

percentage of the original weight of the test sample. This value is reported as the percentage of wear.

Description Sample 1 Sample 2

Weight of aggregate in gm. (A)

Weight of aggregate passing from 1.70mm IS Sieve in gm. (B)

Aggregate Abrassion Value in % = (B/A) X 100

Result: The aggregate Abrasion Value of given sample of coarse aggregate is ……….. %

Faculty Signature

Civil Engineering Department | 12. Slump Test 28

Laboratory Manual


12. Slump Test

Object: To determine the workability or consistency of concrete mix of given proportion by slump test.

Apparatus: Iron pan to mix concrete

Weighing machine

Trowel

Slump cone

Scale and tamping rod etc.

Procedure: Unsupported concrete, when it is fresh, will flow to the sides and a sinking in height will take place. This

vertical settlement is called slump. Slump is a measure for W/C ratio 0.5, 0.6 and 0.7 for each mix take 10 Kg.

C.A., 5 Kg. FA and 2.5 Kg. Cement.

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

2. The internal surface of the mould is to be thoroughly cleaned and placed on a smooth, horizontal,

rigid and non absorbent surface.

3. Place the mixed concrete in the cleaned slump cone in 3 layers each approximately 1/3 in height of

the mould. Tamp each layer 25 times with tamping rod.

4. Remove the cone immediately, rising it slowly and carefully in the vertical direction.

5. As soon as the concrete settlement comes to a stop, measure the subsistence of the concrete in cms,

which gives the slump.

Note: Slump test is adopted in the Laboratory or during the progress of the work in the field for determining

consistency of concrete where nominal max., size of aggregates does not exceed 40 mm. Any slump specimen

which collapses or shears off laterally gives incorrect results and at this juncture the test is repeated only true

slump should be measured.

Observations: SR NO w/c ratio Slump in mm

1 0.5

2 0.6

3 0.7


Laboratory Manual


Precautions: 1. The strokes are to be uniformly applied through the entire area of the concrete section.

2. The cone should be removed very slowly by lifting it upwards without disturbing the concrete.

3. During filling the mould must be firmly pressed against the base.

4. Vibrations from nearly machinery might also increase subsidence; hence test should be made beyond

the range of ground vibrations.


Laboratory Manual


Comments: This test is not a true guide to workability. For example, a harsh coarse mix cannot be said to have same

workability as one with a large portion of sand even though they have the same slump.

Recommended slumps of concrete mix of various works

Degree of workability

Slump (mm) Compacting factor Use for which concrete is suitable

Very low - 0.78-0.80

Roads vibrated by power-operated machines. At the more workable end of this group, concrete may be compacted in certain cases with hand-operated machines.

Low 25-75 0.85-0.87

Roads vibrated by hand-operated machines. At the more workable end of this group, concrete may be manually compacted in roads using aggregate of rounded of irregular shape. Mass concrete foundations without vibration or lightly reinforced sections with vibration.

Medium 50-100 0.92-0.935

At the less workable end of this group, manually compacted flat slabs using crushed aggregates. Normal reinforced concrete manually compacted and heavily reinforced sections with vibration.

High 100-150 0.95-0.96

For sections with congested reinforcement. Not normally suitable for vibration. For pumping and tremie placing.

Very high - - Flow table test is more suitable.

Faculty Signature

Civil Engineering Department | 13. Compacting Factor Test 31

Laboratory Manual


13. Compacting Factor Test Object: To determine the workability of concrete mix of given proportion by compaction factor test.

Apparatus: Compaction factor apparatus

Trowel

Weighing machine

Compacting factor test apparatus etc.

Introduction: This test is adopted to determine workability of concrete where nominal size of aggregate does not exceed 40

mm. It is based on the definition, that workability is that property of concrete, which determines the amount

of work required to produce full compaction.

The test consists essentially of applying a standard amount of work to standard quantity of concrete and

measuring the resulting compaction.

The compaction factor is defined as the ratio of the weight of partially compacted concrete to the weight of

fully compacted concrete. It shall be stated to the nearest second decimal place.

Procedure: Conduct test for W/c ratio 0.5, 0.6, and 0.7, for each mix take 10 kg of coarse aggregate 5kg of fine aggregate

and 2.5 Kg of cement.

1. Grease the inner surface of the hoppers and the cylinder.

2. Fasten the hopper doors.

3. Weigh the empty cylinder accurately (W1. Kgs).

4. Fix the cylinder on the base with fly nuts and bolts

5. Mix coarse and fine aggregates and cement dry until the mixture is uniform in colour and then with

water until concrete appears to be homogeneous.

6. Fill the freshly mixed concrete in upper hopper gently with trowel without compacting.

7. Release the trap door of the upper hopper and allow the concrete of fall into the lower hopper

bringing the concrete into standard compaction.

8. Immediately after the concrete comes to rest, open the trap door of the lower hopper and allow the

concrete to fall into the cylinder, bringing the concrete into standard compaction.

9. Remove the excess concrete above the top of the cylinder by a trowel.

10. Find the weight of cylinder i.e cylinder filled with partially compacted concrete (W2 kgs)


Laboratory Manual


11. Refill the cylinder with same sample of concrete in approx. 4 layers, tamping each layer with tamping

for 25 times in order to obtain full compaction of concrete.

12. Level the mix and weigh the cylinder filled with fully compacted concrete (W3 Kg)

13. Repeat the procedure for different for different a trowel.

Observations and Calculations: Weight of cylinder = W1 Kgs.

SR.NO. W/c ratio

Wt. With

partially

compaction

W2(Kgs)

Wt. With

fully

compaction

W3(Kgs)

Wt. With

partially

compacted

concrete(W2-

W3) (Kgs)

Wt. With fully

compacted

concrete(W3-

W1) (Kgs)

Compaction

factor (W1-

W2)/ (W3-

W1)

1 0.5

2 0.6

3 0.7


Laboratory Manual


Precautions: 1. The top hopper must be filled gently.

2. The mix should not be pressed or compacted in the hopper.

3. If the concrete in the hopper does not fall through when the trap door is released, it should be freed

by passing a metal rod. A single steady penetration will usually affect release.

Comments: It is more sensitive, precise than slump test and is particularly useful to concrete mixes of low workability.

Suggested ranges of values of compaction factors for different placing conditions have been shown in the

table show in slump test experiment.

Faculty Signature

Civil Engineering Department | 14. Compressive Strength Test 34

Laboratory Manual


14. Compressive Strength Test Object: The test method covers determination of compressive strength of cubic concrete specimens. It consists of

applying a compressive axial load to molded cubes at a rate which is within a prescribed range until failure

occurs.

Reference: IS : 516 – 1959

IS: 1199-1959

SP : 23-1982

IS : 10086-1982

Introduction: Age at Test - Tests shall be made at recognized ages of the test specimens, the most usual being 7 and 28

days. Where it may be necessary to obtain the early strengths, tests may be made at the ages of 24 hours ± ½

hour and 72 hours ± 2 hours. The ages shall be calculated from the time of the addition of water to the dry

ingredients.

Number of Specimens - At least three specimens, preferably from different batches, shall be made for testing

at each selected age.

Apparatus: I. Compression Testing Machine

II. Cube Moulds - The mould shall be of 150 mm size conforming to IS: 10086-1982.

III. Weights and weighing device, Tools and containers for mixing, Tamping rod etc.

Procedure: 1. Sampling of Materials - Samples of aggregates for each batch of concrete shall be of the desired

grading and shall be in an air-dried condition. The cement samples, on arrival at the laboratory, shall

be thoroughly mixed dry either by hand or in a suitable mixer in such a manner as to ensure the

greatest possible blending and uniformity in the material.

2. Proportioning - The proportions of the materials, including water, in concrete mixes used for

determining the suitability of the materials available, shall be similar in all respects to those to be

employed in the work.

3. Weighing - The quantities of cement, each size of aggregate, and water for each batch shall be

determined by weight, to an accuracy of 0.1 percent of the total weight of the batch.

4. Mixing Concrete - The concrete shall be mixed by hand, or preferably, in a laboratory batch mixer, in

such a manner as to avoid loss of water or other materials. Each batch of concrete shall be of such a

size as to leave about 10 percent excess after moulding the desired number of test specimens.

Civil Engineering Department | 14. Compressive Strength Test 35

Laboratory Manual


5. Mould - Test specimens cubical in shape shall be 15 × 15 × 15 cm. If the largest nominal size of the

aggregate does not exceed 2 cm, 10 cm cubes may be used as an alternative. Cylindrical test

specimens shall have a length equal to twice the diameter.

6. Compacting - The test specimens shall be made as soon as practicable after mixing, and in such a way

as to produce full compaction of the concrete with neither segregation nor excessive laitance.

7. Curing - The test specimens shall be stored in a place, free from vibration, in moist air of at least 90

percent relative humidity and at a temperature of 27° ± 2°C for 24 hours ± ½ hour from the time of

addition of water to the dry ingredients.

8. Placing the Specimen in the Testing Machine - The bearing surfaces of the testing machine shall be

wiped clean and any loose sand or other material removed from the surfaces of the specimen which

are to be in contact with the compression platens.

9. In the case of cubes, the specimen shall be placed in the machine in such a manner that the load shall

be applied to opposite sides of the cubes as cast, that is, not to the top and bottom.

10. The axis of the specimen shall be carefully aligned with the centre of thrust of the spherically seated

platen. No packing shall be used between the faces of the test specimen and the steel platen of the

testing machine.

11. The load shall be applied without shock and increased continuously at a rate of approximately 140

kg/sq cm/min until the resistance of the specimen to the increasing load breaks down and no greater

load can be sustained.

12. The maximum load applied to the specimen shall then be recorded and the appearance of the

concrete and any unusual features in the type of failure shall be noted.

Observation: Age of cube Wt. of cube

(Kg) Load (P) (N)

c/s area (A)

(mm2)

Compressive strength (N/mm2)

(P/A)

Average compressive

strength (N/mm2)

Result: I. The average ____Days Compressive Strength of concrete sample is found to be ______N/mm2.

II. The average ____ Days Compressive Strength of concrete sample is found to be _______ N/mm2.

Faculty Signature

Civil Engineering Department | 15. Tensile strength test or Split cylinder test 36

Laboratory Manual


15. Tensile strength test or Split

cylinder test Object: This method covers the determination of the splitting tensile strength of cylindrical concrete specimens.

Reference: IS: 516 – 1959

IS: 1199-1959

SP: 23-1982

IS: 10086-1982


days. Where it may be necessary to obtain the early strengths, tests may be made at the ages of 24 hours ±1/2


ingredients.



Apparatus: I. Compression Testing Machine

II. Cylinders -The cylindrical mould shall be of 150 mm diameter and 300 mm height conforming to

IS:10086-1982.

III. Weights and weighing device

IV. Tools and containers for mixing

V. Tamping rod etc.










Civil Engineering Department | 15. Tensile strength test or Split cylinder test 37

Laboratory Manual





5. Mould - The cylindrical mould shall be of 150 mm diameter and 300 mm height conforming to IS:

10086-1982.






8. Placing the Specimen in the Testing Machine - The bearing surfaces of the supporting and loading

rollers shall be wiped clean, and any loose sand or other material removed from the surfaces of the

specimen where they are to make contact with the rollers.

9. Two bearings strips of nominal (1/8 in i.e 3.175mm) thick plywood, free of imperfections,

approximately (25mm) wide, and of length equal to or slightly longer than that of the specimen

should be provided for each specimen.

10. The bearing strips are placed between the specimen and both upper and lower bearing blocks of the

testing machine or between the specimen and the supplemental bars or plates.

11. Draw diametric lines an each end of the specimen using a suitable device that will ensure that they

are in the same axial plane. Center one of the plywood strips along the center of the lower bearing

block.

12. Place the specimen on the plywood strip and align so that the lines marked on the ends of the

specimen are vertical and centered over the plywood strip.

13. Place a second plywood strip lengthwise on the cylinder, centered on the lines marked on the ends of

the cylinder.

14. Apply the load continuously and without shock, at a constant rate within, the range of 689 to 1380

kPa/min splitting tensile stress until failure of the specimen

15. Record the maximum applied load indicated by the testing machine at failure. Note the type of failure

and appearance of fracture.

Observation: Age of

cylinder Wt. of

cylinder (Kg)

Load (N)-P Length (mm)

Diameter (mm)

Tensile strength (N/mm2)

[2P/ πLD]

Average tensile

strength (N/mm2)

Result: I. The average ____Days Tensile Strength of concrete sample is found to be ______N/mm2.

Faculty Signature

Civil Engineering Department | 16. Flexural Strength test 38

Laboratory Manual


16. Flexural Strength test Object: This clause deals with the procedure for determining the flexural strength of moulded concrete flexure test

specimens

Reference: IS : 516 – 1959

IS: 1199-1959

SP : 23-1982

IS : 10086-1982


days. Where it may be necessary to obtain the early strengths, tests may be made at the ages of 24 hours ±½


ingredients.



Apparatus: I. Testing Machine - The testing machine may be of any reliable type, of sufficient capacity for the tests

and capable of applying the load at the rate specified in 5.5. The permissible error shall be not greater

than ± 2 percent of the maximum load.

II. Beam Moulds - The beam moulds shall conform to IS: 10086-1982. The standard size shall be 15 × 15 ×

70 cm. Alternatively, if the largest nominal size of the aggregate does not exceed 19 mm, specimens

10 × 10 × 50 cm may be used.

III. Weights and weighing device, Tools and containers for mixing, Tamper (square in cross section) etc.










Civil Engineering Department | 16. Flexural Strength test 39

Laboratory Manual





5. Mould - The standard size shall be 15 × 15 × 70 cm. Alternatively, if the largest nominal size of the

aggregate does not exceed 19 mm, specimens 10 × 10 × 50 cm may be used.






8. Placing the Specimen in the Testing Machine - The bearing surfaces of the supporting and loading

rollers shall be wiped clean, and any loose sand or other material removed from the surfaces of the

specimen where they are to make contact with the rollers.

9. The specimen shall then be placed in the machine in such a manner that the load shall be applied to

the uppermost surface as cast in the mould, along two lines spaced 20.0 or 13.3 cm apart.

10. The axis of the specimen shall be carefully aligned with the axis of the loading device. No packing shall

be used between the bearing surfaces of the specimen and the rollers.

11. The load shall be applied without shock and increasing continuously at a rate such that the extreme

fibre stress increases at approximately 7 kg/sq cm/min, that is, at a rate of loading of 400 kg/min for

the 15.0 cm specimens and at a rate of 180 kg/min for the 10.0 cm specimens.

12. The load shall be increased until the specimen fails, and the maximum load applied to the specimen

during the test shall be recorded. The appearance of the fractured faces of concrete and any unusual

features in the type of failure shall be noted.

Observation: Age of

beam

Wt. of

beam (Kg)

Load (P) (N)

Length (l)

(mm)

Breadth (b)

(mm)

Depth (d)

(mm)

Flexural strength (N/mm2)

[P*l/b*d2] (centre-point

loading)

Average Flexural strength (N/mm2)

Flexural strength (N/mm2)

[P*l/b*d2] (third-point

loading)

Average Flexural strength (N/mm2)

Result: I. The average ____Days Flexural Strength of concrete sample with centre-point loading is found to be

______N/mm2.

II. The average ____ Days Flexural Strength of concrete sample with third-point loading is found to be

_______ N/mm2.

Faculty Signature

Documents

Darshan Institute of Engineering & Technology...IS: 4031 (Part 1) -1996 Introduction: The fineness of cement has an important bearing on the rate of hydration and hence on the rate