1 Lab Manual of Concrete Technology - SGI

Department of Civil Engineering Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur 1 Lab Manual of Concrete Technol...

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Lab Manual of Concrete Technology

1

Prepared By

Chetan S. Patil Assistant Professor

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

2 Introduction

:

The behavior and properties of structural materials, e.g. concrete, asphalt and steel can be better understood by detailed, well-designed, first hand experience with these materials. The students will become familiar with the nature and properties of these materials by conducting laboratory tests. These tests have been selected to illustrate the basic properties and methods of testing of cement, aggregates, paste, mortar, concrete, asphalt and steel. Test procedures, sometimes simplified because of time limitation, are mostly those outlined by the Indian Standards.

Course Objectives

1. To prepare the students to effectively link theory with practice and application and to demonstrate background of the theoretical aspects.

2. To prepare the students to generate and analyze data using experiments and to apply elements of data statistics.

3. To prepare the students to have hands on experiments and to have exposure to equipment and machines

4. To prepare the students to solve problems including design elements and related to their course work. 5. To encourage the students to use computers in analyzing the data. 6. To emphasize the knowledge and application of safety regulations. Student Responsibilities

1. In the very beginning of the laboratory work, the students will be organized into groups. For this reason, regular attendance is strictly required.

2. Every laboratory session is divided into two parts. In the first part, the instructor will be lecturing on the test objective, procedure and data collection. In the second part, the students, organized in groups, are required to conduct the field work. In order to perform the field work within the assigned period, and to gain the maximum benefit from the field work, the students must familiarize themselves with the purpose, objective, and procedure of the experiment before coming to the laboratory. Relevant lecture notes and laboratory manual should be studied carefully and thoroughly.

3. At the end of the test, every group should submit a draft sheet of the data collected for approval by the instructor.

4. It should be understood that laboratory facilities and instruments are provided to enhance the learning process and to give first hand experience of surveying.

5. The instruments and tools must be properly cared and cleaned during and after every laboratory Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

session. Also, students should always take precautions to avoid any possible hazards. Students must follow laboratory regulations provided at the end of this section.

Report Writing Every student is required to submit his own separate report for each test conducted. Reports should be writing on 8½ x 11 in. high-quality paper. In general, the reports should be arranged in the following order:

Laboratory Regulations

1. Make sure that you know the location of Fire Extinguishers, First Aid Kit and Emergency Exits before you start your experiments.

2. Get First Aid immediately for any injury, no matter how small it is. 3. Do not wear loose dress 4. Always use close shoes (i.e. safety or boots) 5. Do not play with valves, screws and nuts 6. Do not try to run and operate any machine without permission and knowledge of the lab. personnel List of Experiment as per Shivaji University Curriculum Sr. No.

1.

Page No

Name of Experiment

From

To

Testing of cement: Consistency, fineness, setting time, Specific Gravity, Soundness and strength.

2.

Testing of fine aggregate: Specific Gravity, sieve analysis and zoning, bulking of fine aggregate, bulk density, silt content.

3.

Testing of coarse aggregate: Specific Gravity, sieve analysis, bulk density, flakiness index, elongation index, water absorption & moisture content, soundness of aggregate.

4.

Concrete Mix design by ACI 211.1-91 method, IS code method as per 102622007 & 456-2000, DOE method

5.

Tests on Concrete- Workability tests – Slump cone test, compaction factor test, Vee-bee consistometer test, flow table test, strength tests- compressive strength, flexural strength, split tensile strength.

6.

Effects of Admixture - Accelerator, Retarder, Super Plasticizer.

7.

Nondestructive Testing - Rebound Hammer test, Ultrasonic Pulse Velocity test. Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

3

4

Experiment No.

: 01(a)

Date

Title

: Determination of Consistency of Standard Cement Paste

Objective

:

To determine the normal consistency of a given sample of cement.

Reference

:

IS : 4031 ( Pat 4 ) - 1988, IS : 5513-1976,

Theory

:

For finding out initial setting time, final setting time and soundness of cement, and strength a parameter known as standard consistency has to be used. The standard consistency of a cement paste is defined as that consistency which will permit a Vicat plunger having 10 mm diameter and 50 mm length to penetrate to a depth of 33-35 mm from the top of the mould.

Apparatus

:

Vicat apparatus conforming to IS : 5513-1976, Balance, Gauging Trowel, Stop Watch, etc.

Procedure

:

1. The standard consistency of a cement paste is defined as that consistency which will permit the Vicat plunger to penetrate to a point 5 to 7 mm from the bottom of the Vicat mould

2. Initially a cement sample of about 300 g is taken in a tray and is mixed with a known percentage of water by weight of cement, say starting from 26% and then it is increased by every 2% until the normal consistency is achieved.

3. Prepare a paste of 300 g of Cement with a weighed quantity of potable or distilled water, taking care that the time of gauging is not less than 3 minutes, nor more than 5 min, and the gauging shall be completed before any sign of setting occurs. The gauging time shall be counted from the time of adding water to the dry cement until commencing to fill the mould.

4. Fill the Vicat mould (E) with this paste, the mould resting upon a non-porous plate. After completely filling the mould, smoothen the surface of the paste, making it level with the top of the mould. The mould may be slightly shaken to expel the air.

5. Place the test block in the mould, together with the non-porous resting plate, under the rod bearing the plunger; lower the plunger gently to touch the surface of the test block, and quickly release, allowing it to sink into the paste. This operation shall be carried out immediately after filling the mould.

6. Prepare trial pastes with varying percentages of water and test as described above until the amount of Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

5

water necessary for making up the standard consistency as defined in Step 1 is found. Figure

:

Observation

:

Express the amount of water as a percentage by mass of the dry cement to the first place of decimal. Sr. No.

Weight of cement (gms)

Percentage by water of dry Cement (%)

Amount of water added (ml)

Penetration (mm)

1 2 3 4

Conclusion / R

:

The normal consistency of a given sample of cement is _ _ _ _ %

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

6

Experiment No.

:

01(b)

Date

Title

:

Determination of Setting Time of Standard Cement Paste

Objective

:

To determine the initial and final setting time of a given sample of cement.

Reference

:

IS : 4031 ( Pat 4 ) -1988, IS : 4031 ( Pat 5 ) - 1988, IS : 5513-1976,

Theory

:

For convenience, 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 definite pressure.

Apparatus

:

Vicat apparatus conforming to IS : 5513-1976, Balance, Gauging Trowel, Stop Watch, etc.

Procedure

:

1. Preparation of Test Block - Prepare a neat 300 gms cement paste by gauging the cement with 0.85 times the water required to give a paste of standard consistency. Potable or distilled water shall be used in preparing the paste.

2. Start a stop-watch at the instant when water is added to the cement. Fill the Vicat mould with a cement paste gauged as above, the mould resting on a nonporous plate. Fill the mould completely and smooth off the surface of the paste making it level with the top of the mould.

3. Immediately after moulding, place the test block in the moist closet or moist room and allow it to remain there except when determinations of time of setting are being made.

4. Determination of Initial Setting Time - Place the test block confined in the mould and resting on the non-porous plate, under the rod bearing the needle ( C ); lower the needle gently until it comes in contact with the surface of the test block and quickly release, allowing it to penetrate into the test block

5. Repeat this procedure until the needle, when brought in contact with the test block and released as described above, fails to pierce the block beyond 5.0 ± 0.5 mm measured from the bottom of the mould shall be the initial setting time.

6. Determination of Final Setting Time - Replace the needle (C) of the Vicat apparatus by the needle with an annular attachment (F). Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

7. 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 thereon, while the attachment fails to do so.

8. The period elapsing 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.

Figure

:

Observation

:

1. Weight of given sample of cement is _ _ _ _ gms 2. The normal consistency of a given sample of cement is _ _ _ _ % 3. Volume of water addend (0.85 times the water required to give a paste of standard consistency) for preparation of test block _ _ _ _ ml Setting Time (Sec)

Sr. No.

Penetration (mm)

Remark

1 2 3

Conclusion / Result

:

i) The initial setting time of the cement sample is found to be ….. ii) The final setting time of the cement sample is found to be ….. Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

7

8

Experiment No.

: 01(c)

Date

Title

: Determination of Fineness of Cement by dry sieving

Objective

:

To determine the normal consistency of a given sample of cement.

Reference

:

IS : 4031 ( Pat 1 ) - 1988,

Theory

:

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 for hydration and hence faster the development of strength, (Fig. 3). The fineness of grinding has increased over the years. But now it has got nearly stabilized. Different cements are ground to different fineness. The particle size fraction below 3 microns has been found to have the predominant effect on the strength at one day while 3-25 micron fraction has a major influence on the 28 days strength. Increase in fineness of cement is also found to increase the drying shrinkage of concrete.

Fineness of cement is tested in two ways : (a) By sieving. (b) By determination of specific surface (total surface area of all the particles in one gram of cement) by air-permeability apparatus. Expressed as cm2/gm or m2/kg. Generally Blaine Air permeability apparatus is used. Apparatus

:

Procedure

:

Test Sieve 90 microns, Balance, Gauging Trowel, Brush, etc.

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

1. Fit the tray under the sieve, weigh approximately 10 g of cement to the nearest 0.01 g and place it on the sieve, being careful to avoid loss. Fit the lid over the sieve. Agitate the sieve by swirling, planetary and linear movement until no more fine material passes through it.

2. Remove and weigh the residue. Express its mass as a percentage, R1, of the quantity first placed in the sieve to the nearest 0.1 percent. Gently brush all the fine material off the base of the sieve into the tray.

3. Repeat the whole procedure using a fresh 10 g sample to obtain R2. Then calculate the residue of the cement R as the mean of R1, and R2, as a percentage, expressed to the nearest 0.1 percent.

4. When the results differ by more than 1 percent absolute, carry out a third sieving and calculate the mean of the three values.

Conclusion / R

:

The fineness of a given sample of cement is _ _ _ _ %

Experiment No.

:

01(d)

Title

:

Determination of Soundness of Cement by Le-Chatelier method

Objective

:

To determine the soundness of a given sample of cement by Le-Chatelier

Date

method.

Reference

:

Theory

:

IS : 4031 ( Pat 3 ) - 1988,

It is very important that the cement after setting shall not undergo any appreciable change of volume. Certain cements have been found to undergo a large expansion after setting causing disruption of the set and hardened mass. This will cause serious difficulties for the durability of structures when such cement is used. The unsoundness in cement is due to the presence of excess of lime than that could be combined with acidic oxide at the kiln. It is also likely that too high a proportion of magnesium content or calcium sulphate content may cause unsoundness in cement. Soundness of cement may be determined by two methods, namely Le-Chatelier method and autoclave method

Apparatus

:

Le- Chatelier test apparatus conform to IS : 5514-1969, Balance, Gauging Trowel, Water Bath etc.

Procedure

: Department of Civil Engineering

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9

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 [see IS : 4031 (Part 4)-1988 or experiment No. 1(a) ].

2. The paste shall be gauged in the manner and under the conditions prescribed in experiment No.1, taking care to keep the edges of the mould gently together while this operation is being performed.

3. Cover the mould with another piece of lightly oiled glass sheet, place a small weight on this covering glass sheet and immediately submerge the whole assembly in water at a temperature of 27 ± 2°C and keep there for 24 hours.

4. Measure the distance separating the indicator points to the nearest 0.5 mm. Submerge the mould again in water at the temperature prescribed above.

5. Bring the water to boiling, with the mould kept submerged, in 25 to 30 minutes, and keep it boiling for three hours. Remove the mould from the water, allow it to cool and measure the distance between the indicator points.

6. The difference between these two measurements indicates the expansion of the cement. This must not exceed 10 mm for ordinary, rapid hardening and low heat Portland cements. If in case the expansion is more than 10 mm as tested above, the cement is said to be unsound.

Figure

:

Observation

:

Express the amount of water as a percentage by mass of the dry cement to the first place of decimal.

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

10

Sr. No.

Distance separating the indicator submerge in normal temp water for 24 hours

Distances separating the indicator submerge in boiling for three hours.

The difference between these two measurements

11 Remark

1 2 3 4

Conclusion / R

:

The given cement is said to be sound / unsound.

Experiment No.

:

01(d)

Title

:

Determination of Compressive Strength of Cement

Objective

:

To determine the compressive strength of a given sample of cement.

Reference

:

IS : 4031 ( Pat 6 ) - 1988, IS : 10080-1982, IS : 650-1966, IS: 269-1976

Theory

:

Date

The compressive strength of hardened cement is the most important of all the properties. Therefore, it is not surprising that the cement is always tested for its strength at the laboratory before the cement is used in important works. Strength tests are not made on neat cement paste because of difficulties of excessive shrinkage and subsequent cracking of neat cement. Apparatus

:

The standard sand to be used in the test shall conform to IS : 650-1966, Vibration Machine, Poking Rod, Cube Mould of 70.6 mm size conforming to IS : 10080-1982, Balance, Gauging Trowel, Stop Watch, Graduated Glass Cylinders, etc.

Procedure

:

1. Preparation of test specimens - Clean appliances shall be used for mixing and the temperature of water and that of the test room at the time when the above operations are being performed shall be 27 ± 2°C. Potable/distilled water shall be used in preparing the cubes.

2. The material for each cube shall be mixed separately and the quantity of cement, standard sand and water shall be as follows: Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

12

Cement 200 g and Standard Sand 600 g

P  Water   0.3  percent of combined mass of cement and sand, where P is the percentage of water 4  required to produce a paste of standard consistency determined as described in IS : 4031 (Part 4)-1988 or Experiment No.1(a).

3. Place on a nonporous plate, a mixture of cement and standard sand. Mix it dry with a trowel for one minute and then with water until the mixture is of uniform colour. The quantity of water to be used shall be as specified in step 2. The time of mixing shall in any event be not less than 3 min and should the time taken to obtain a uniform colour exceed 4 min, the mixture shall be rejected and the operation repeated with a fresh quantity of cement, sand and water.

4. Moulding Specimens - In assembling the moulds ready for use, treat the interior faces of the mould with a thin coating of mould oil.

5. Place the assembled mould on the table of the vibration machine and hold it firmly in position by means of a suitable clamp. Attach a hopper of suitable size and shape securely at the top of the mould to facilitate filling and this hopper shall not be removed until the completion of the vibration period.

6. Immediately after mixing the mortar in accordance with step 1 & 2, place the mortar in the cube mould and prod with the rod. Place the mortar in the hopper of the cube mould and prod again as specified for the first layer and then compact the mortar by vibration.

7. The period of vibration shall be two minutes at the specified speed of 12 000 ± 400 vibration per minute.

8. At the end of vibration, remove the mould together with the base plate from the machine and finish the top surface of the cube in the mould by smoothing the surface with the blade of a trowel.

9. Curing Specimens - keep the filled moulds in moist closet or moist room for 24 ± 1 hour after completion of vibration. At the end of that period, remove them from the moulds and immediately submerge in clean fresh water and keep there until taken out just prior to breaking.

10. The water in which the cubes are submerged shall be renewed every 7 days and shall be maintained at a temperature of 27 ± 2°C. After they have been taken out and until they are broken, the cubes shall not be allowed to become dry.

11. Test three cubes for compressive strength for each period of curing mentioned under the relevant specifications (i.e. 3 days, 7 days, 28 days)

12. The cubes shall be tested on their sides without any packing between the cube and the steel plattens of the testing machine. One of the plattens shall be carried on a base and shall be self-adjusting, and the load shall be steadily and uniformly applied, starting from zero at a rate of 35 N/mm2/min.

Figure

: Department of Civil Engineering

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13

Observation

Sr. No.

Age of Cube

:

Weight of Cement Cube (gms)

CrossSectional area (mm2)

Load (N)

Compressive strength (N/mm2)

Average Compressive strength (MPa)

1 2

7 Days

3 4 5

28 Days

`

6

Calculation

:

The measured compressive strength of the cubes shall be calculated by dividing the maximum load applied to the cubes during the test by the cross-sectional area, calculated from the mean dimensions of the section and shall be expressed to the nearest 0.5 N/mm2. In determining the compressive strength, do not consider specimens that are manifestly faulty, or that give strengths differing by more than 10 percent from the average value of all the test specimens.

Conclusion / Result

:

i) The average 3 Days Compressive Strength of given cement sample is found to be …..….. ii) The average 7 Days Compressive Strength of given cement sample is found to be …..….. iii) The average 28 Days Compressive Strength of given cement sample is found to be …..…..

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

14

Experiment No.

: 02(a)

Date

Title

: Particle Size Distribution of Fine Aggregates

Objective

:

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

Reference

:

Theory

:

IS : 2386 ( Part I) – 1963, IS: 383-1970, IS : 460-1962

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 coarse sand, medium sand and fine sand. These classifications do not give any precise meaning. What the supplier terms as fine sand may be really medium or even coarse sand. To avoid this ambiguity fineness modulus could be used as a yard stick to indicate the fineness of sand. The following limits may be taken as guidance: Fine sand : Fineness Modulus : 2.2 - 2.6, Medium sand : F.M. : 2.6 - 2.9, Coarse sand : F.M. : 2.9 - 3.2 Sand having a fineness modulus more than 3.2 will be unsuitable for making satisfactory concrete. Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

15 Apparatus

:

Test Sieves conforming to IS : 460-1962 Specification of 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron, 150 micron, Balance, Gauging Trowel, Stop Watch, etc.

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 sand 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 and 75-micron IS Sieves to prevent aggregation of powder and blinding of apertures.

5. On completion of sieving, the material retained on each sieve, together with any material cleaned from the mesh, shall be weighed.

Observation I S Sieve

: Weight Retained on Sieve (gms)

Percentage of Weight Retained (%)

Percentage of Weight Passing (%)

Cumulative Percentage of Passing (%)

Remark

4.75 mm 2.36 mm 1.18 mm 600 micron 300 micron 150 micron Total

Calculation

:

Fineness modulus is an empirical factor obtained by adding the cumulative percentages of aggregate retained on each of the standard sieves ranging from 4.75 mm to 150 micron and dividing this sum by an Department of Civil Engineering

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16

arbitrary number 100.  Total of Cumulative Percentage of Passing (%)  Finess Modulus, FM    100  

Conclusion / Result

:

i) Fineness modulus of a given sample of fine aggregate is …….. that indicate Coarse sand/ Medium sand/ Fine sand. ii) The given sample of fine aggregate is belong to Grading Zones I / II / III / IV

Experiment No.

:

02(b)

Date

Title

:

Determination of Bulking of Fine Aggregate

Objective

:

To determine bulking of a given sample of fine aggregate.

Reference

:

IS : 2386 ( Part III ) - 1963

Theory

:

Free moisture forms a film around each particle. This film of moisture exerts what is known as surface tension which keeps the neighbouring particles away from it. Similarly, the force exerted by surface tension keeps every particle away from each other. Therefore, no point contact is possible between the particles. This causes bulking of the volume. It is interesting to note that the bulking increases with the increase in moisture content upto a certain limit and beyond that the further increase in the moisture content results in the decrease in the volume and at a moisture content representing saturation point, the Department of Civil Engineering

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17

fine aggregate shows no bulking.

Apparatus

:

Procedure

:

Measuring jar, Taping rod etc.

1. Put sufficient quantity of the sand loosely into a container. Level off the top of the sand and pushing a steel rule vertically down through the sand at the middle to the bottom, measure the height. Suppose this is h1 cm.

2. Empty the sand out of the container into another container where none of it will be lost. Half fill the first container with water. Put back about half the sand and rod it with a steel rod, about 6 mm in diameter, so that its volume is reduced to a minimum. Then add the remainder of the sand and rod it in the same way.

3. The percentage of bulking of the sand due to moisture shall be calculated from the formula: h  Percentage Bulking    1 100  h1  Conclusion / Result

:

Bulking of a given sample of fine aggregate is found to be ……. %

Experiment No.

:

02(c)

Title

:

Determination of Silt Content in Fine Aggregate

Objective

:

To determine silt content in a given sample of fine aggregate by sedimentation

Date

method.

Reference

:

IS : 2386 ( Part II ) - 1963

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

18 Theory

:

This is a gravimetric method for determining the clay, fine silt and fine dust, which includes particles up to 20 micron. Differences in the nature and density of materials or in the temperature at the time of testing may vary the separation point. Apparatus

:

A watertight screw-topped glass jar of dimensions similar to a 1-kg fruit preserving jar, A device for rotating the jar about its long axis, with this axis horizontal, at a speed of 80 ± 20 rev/min, A sedimentation pipette, A 1 000-ml measuring cylinder, scale, well-ventilated oven, Taping rod etc.

Chemical

:

A solution containing 8 g of sodium oxalate per liter of distilled water shall be taken. For use, this stock solution is diluted with distilled water to one tenth (that is 100 ml diluted with distilled water to one liter).

Figure

:

Procedure

:

1. Approximately 300 g of the sample in the air-dry condition, passing the 4.75-mm IS Sieve, shall be weighed and placed in the screw-topped glass jar, together with 300 ml of the diluted sodium oxalate Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

solution. The rubber washer and cap shall be fixed, care being taken to ensure water tightness.

2. The jar shall then be rotated about its long axis, with this axis horizontal, at a speed of 80 ± 20 rev/min for a period of 15 minutes

3. At the end of 15 minutes, the suspension shall be poured into the 1 000-ml measuring cylinder and the residue washed by gentle swirling and decantation of successive 150-ml portions of sodium oxalate solution, the washings being added to the cylinder until the volume is made up to 1000 ml.

4. The suspension in the measuring cylinder shall be thoroughly mixed by inversion and the tube and contents immediately placed in position under the pipette.

5. The pipette A shall then be gently lowered until the tip touches the surface of the liquid, and then lowered a further 10 cm into the liquid.

6. Three minutes after placing the tube in position, the pipette A and the bore of tap B shall be filled by opening B and applying gentle suction at C.

7. A small surplus may be drawn up into the bulb between tap B and tube C, but this shall be allowed to run away and any solid matter shall be washed out with distilled water from E.

8. The pipette shall then be removed from the measuring cylinder and its contents run into a weighed container, any adherent solids being washed into the container by distilled water from E through the tap B.

9. The contents of the container shall be dried at 100 to 110°C to constant weight, cooled and weighed. 10. Calculations— The proportion of fine silt and clay or fine dust shall then be calculated from the following formula:

Percentage of clay and fine silt or fine dust 

100  1000W2   0.8   W1  V 

W1 = weight in g of the original sample, W2 = weight in g of the dried residue, V = volume in ml of the pipette, and 0.8 = weight in g of sodium oxalate in one litre of the diluted solution

Conclusion / Result

:

The clay, fine silt and fine dust content of given sample of fine aggregate is found to be ……. %

Experiment No.

:

02(d)

Date

Title

:

Determination of Specific Gravity of Fine Aggregate Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

19

Objective

:

To determine specific gravity of a given sample of fine aggregate.

Reference

:

IS : 2386 ( Part III ) - 1963

Apparatus

:

Pycnometer, A 1 000-ml measuring cylinder, well-ventilated oven, Taping rod, Filter papers and funnel, etc.

Figure

:

Procedure

:

1. A sample of about 500 g shall be placed in the tray and covered with distilled water at a temperature of 22 to 32°C. Soon after immersion, air entrapped in or bubbles on the surface of the aggregate shall be removed by gentle agitation with a rod. The sample shall remain immersed for 24 ± l/2 hours.

2. The water shall then be carefully drained from the sample, by decantation through a filter paper, any material retained being return& to the sample. The fine aggregate including any solid matter retained on the filter paper shall be exposed to a gentle current of warm air to evaporate surface moisture and the material just attains a ‗free-running‘ condition. The saturated and surface-dry sample shall be weighed (weight A).

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

4. The contents of the pycnometer shall be emptied into the tray, care being taken to ensure that all the Department of Civil Engineering

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20

aggregate is transferred. The pycnometer shall be refilled with distilled water to the same level as before, dried on the outside and weighed (weight C).

5. The water shall then be carefully drained from the sample by decantation through a filter paper and any material retained returned to the sample. The sample shall be placed in the oven in the tray at a temperature of 100 to 110°C for 24 f l/2 hours, during which period it shall be stirred occasionally to facilitate drying. It shall be cooled in the air-tight container and weighed (weight D).

6. Calculations— Specific gravity, apparent specific gravity and water &sorption shall be calculated as follows:

  D  Specifc Gravity     A  B  C     D  Apparent Specifc Gravity    D  B  C   100 A  D  Water Absorption  D A  weight in g of saturated surface - dry sample, B  weight in g of pycnometer or gas jar containing sample and filled with distilled water, C  weight in g of pycnometer or gas jar filled with distilled water only, and D  weight in g of oven - dried sample. Conclusion / Result

:

i) The Specific Gravity 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 ……. %

Experiment No.

:

03 (a)

Date

Title

:

Determination of Specific Gravity of Course Aggregate

Objective

:

To determine specific gravity of a given sample of course aggregate.

Reference

:

IS : 2386 ( Part III ) - 1963

Apparatus

:

A wire basket of not more than 6-3 mm mesh, A stout watertight container in which the basket may be freely suspended, well-ventilated oven, Taping rod, An airtight container of capacity similar to that of the Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

21

22

basket, etc.

Figure

:

Procedure

:

1. A sample of not less than 2000 g of the aggregate shall be thoroughly washed to remove finer particles and dust, drained and then placed in the wire basket and immersed in distilled water at a temperature between 22°C to 32°C with a cover of at least 5 cm of water above the top of the basket.

2. Immediately. after immersion the entrapped air shall be removed from the sample by lifting the basket containing it 25 mm above the base of the tank and allowing it to drop 25 times at the rate of about one drop per second. The basket and aggregate shall remain completely immersed during the operation and for a period of 24 ± l/2 hours afterwards.

3. The basket and the sample shall then be jolted and weighed in water at a temperature of 22°C to 32°C (weight A1).

4. The basket and the aggregate shall then be removed from the water and allowed to drain for a few minutes, after which the, aggregate shall be gently emptied from the basket on to one of the dry clothes, and the empty basket shall be returned to the water and weighed in water ( weight A2 ).

5. The aggregate placed on the dry cloth shall be gently surface dried with the cloth, transferring it to the second dry cloth when the first will remove no further moisture. The aggregate shall then be weighed (weight B).

6. The aggregate shall then be placed in the oven in the shallow tray, at a temperature of 100 to 110°C and maintained at this temperature for 24 ± l/2 hours. It shall then be removed from the oven, cooled in the airtight container and weighed (weight C).

7. Calculations— Specific gravity, apparent specific gravity and water &sorption shall be calculated as Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

23

follows:

Specifc Gravity 

C A B

C CB 100B  C  Water Absorption  C A  Weight of saturated aggregate in water  (A1 - A 2 ) ApparentSpecifc Gravity 

B  Weight of the saturated surface - dry aggregate in air C  Weight of ovendried aggregate in air. A1  Weight of aggregate and basket in water A 2  Weight of empty basket in water

Conclusion / Result

:

i) The Specific Gravity of a given sample of course aggregate is found to be ……. ii) The Water Absorption of a given sample of course aggregate is found to be ……. %

Experiment No.

:

03(b)

Date

Title

:

Particle Size Distribution of Course Aggregates

Objective

:

To determination of particle size distribution of coarse aggregates by sieving or screening.

Reference

:

Theory

:

IS : 2386 ( Part I) – 1963, IS: 383-1970, IS : 460-1962

Grading refers to the determination of the particle-size distribution for aggregate. Grading limits and maximum aggregate size are specified because grading and size affect the amount of aggregate used as well as cement and water requirements, workability, pumpability, and durability of concrete. In general, if the water-cement ratio is chosen correctly, a wide range in grading can be used without a major effect on strength. When gap-graded aggregate are specified, certain particle sizes of aggregate are omitted from the size continuum. Gap-graded aggregate are used to obtain uniform textures in exposed aggregate concrete. Close control of mix proportions is necessary to avoid segregation.

Apparatus

: Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

Test Sieves conforming to IS : 460-1962 Specification of 80 mm, 40 mm, 20 mm, 10 mm, 4.75 mm, Balance, Gauging Trowel, Stop Watch, etc.

Procedure

:

1. The sample shall be brought to an air-dry condition before weighing and sieving. This may be achieved either by drying at room temperature or by heating at a temperature of 100‖ to 110°C. 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. Each sieve shall be shaken separately over a clean tray until not more than a trace passes, but in any case for a period of not less than two minutes. The shaking shall be done with a varied motion, backward sand 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. On completion of sieving, the material retained on each sieve, together with any material cleaned from the mesh, shall be weighed.

Observation I S Sieve

: Weight Retained on Sieve (gms)

Percentage of Weight Retained (%)

Percentage of Weight Passing (%)

Cumulative Percentage of Passing (%)

Remark

80 mm 40 mm 20 mm 10 mm 4.75 mm Total

Conclusion / Result

:

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

24

25

Experiment No.

:

3(c)

Date

Title

:

Determination of Flakiness Index and Elongation Index of Course Aggregates

Objective

:

To determination of Flakiness Index and Elongation Index of Course Aggregates.

Reference

:

Theory

:

IS : 2386 ( Part I) – 1963, IS: 383-1970, IS : 460-1962

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.

Procedure

:

1. Sample - A quantity of aggregate shall be taken sufficient to provide the minimum number of 200 Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

26

pieces of any fraction to be tested.

2. Sieving - The sample shall be sieved in accordance with the method described in Exp. 3(b) with the sieves specified in Table 3.18.

3. Separation of Flaky material- Each fraction shall be gauged in turn for thickness on a metal gauge of the pattern shown in Fig. 11.1, or in bulk on sieves having elongated slots. The width of the slot used in the gauge or sieve shall be of the dimensions specified in co1 3 of Table 3.18 for the appropriate size of material.

4. Weighing of Flaky Material - The total amount passing the gauge shall be weighed to an accuracy of at least 0.1 percent of the weight of the test sample.

5. The flakiness index is the total weight of the material passing the various thickness gauges or sieves, expressed as a percentage of the total weight of the sample gauged.

6. Sieving - The sample shall be sieved in accordance with the method described in Exp. 3(b) with the sieves specified in Table 3.18.

7. Separation of Elongated Material- Each fraction shall be gauged individually for length on a metal length gauge of the pattern shown in Fig. 11.2. The gauge length used shall be that specified in co1 4 of Table 3.18 for the appropriate size of material.

8. Weighing of Elongated Material - The total amount retained by the length gauge shall be weighed to an accuracy of at least 0.1 percent of the weight of the test sample.

9. The elongation index is the total weight of the material retained on the various length gauges, expressed as a percentage of the total weight of the sample gauged.

Figure

:

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

27

Figure No. 11.1

Figure No. 11.2

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

Observation

28

:

1. Total weight of course aggregate. . . . . . . g (Flakiness Index) Size of Aggregate Thickness Thickness Gauge mm

Passing through IS Sieves

Retained on IS Sieves

63 mm

50 mm

33.90

50 mm

40 mm

27.00

40 mm

25 mm

19.60

31 mm

25 mm

16.95

25 mm

20 mm

13.50

20 mm

16 mm

10.80

16 mm

12 mm

8.55

12.5 mm

10 mm

6.75

10 mm

6.3 mm

4.89

Weight Retained on Thickness Gauge

Percentage of Weight Retained (%)

Remark

Percentage of Weight Retained (%)

Remark

Total

2. Total weight of course aggregate. . . . . . . g (Elongation Index) Size of Aggregate Thickness

Length Gauge mm

Passing through IS Sieves

Retained on IS Sieves

63 mm

50 mm

--

50 mm

40 mm

81.0

40 mm

25 mm

58.5

31 mm

25 mm

--

25 mm

20 mm

40.5

20 mm

16 mm

32.4

16 mm

12 mm

25.6

12.5 mm

10 mm

20.2

10 mm

6.3 mm

14.7

Weight Retained on Length Gauge

Total Calculation

:

 Total of Percentage of Retained on Thickness Gauge (%)  The Flakiness index on an aggregate is    100   Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

 Total of Percentage of Retained on Length Gauge (%)  The elongation index on an aggregate is    100  

Conclusion / Result

:

i) The flakiness index of a given sample of fine aggregate is ………. % ii) The elongation index of a given sample of fine aggregate is ……..%

Experiment No.

:

3(d)

Date

Title

:

Determination of Soundness of Course Aggregates

Objective

:

To determination of Soundness of Course Aggregates.

Reference

:

IS : 2386 ( Part V) – 1963, IS: 383-1970, IS : 460-1962

Theory

:

Soundness refers to the ability of aggregate to resist excessive changes in volume as a result of changes in physical conditions. These physical conditions that affect the soundness of aggregate are the freezing the thawing, variation in temperature, alternate wetting and drying under normal conditions and wetting and drying in salt water. Aggregates which are porous, weak and containing any undesirable extraneous matters undergo excessive volume change when subjected to the above conditions. If concrete is liable to be exposed to the action of frost, the Soundness refers to the ability of aggregate to resist excessive changes in volume as a result of changes in physical conditions. Aggregates which are porous, weak and containing any undesirable extraneous matters undergo excessive volume change when subjected to the above conditions. Aggregates which undergo more than the specified amount of volume change is said to be unsound aggregates. If concrete is liable to be exposed to the action of frost, the coarse and fine aggregate which are going to be used should be subjected to soundness test.

Apparatus

:

Test Sieves conforming to IS : 460-1962 Specification of 80 mm, 63mm, 50 mm, 40 mm, 31.5 mm, 25 mm, 20 mm, 16 mm, 10 mm, 8.0 mm for Coarse, Drying Oven , Containers, Balance, Gauging Trowel, Stop Watch, etc.

Chemical

: Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

29

1. Sodium Sulphate Solution - Saturated solution of sodium sulphate shall be prepared by dissolving sodium sulphate, technical grade, conforming to IS : 255 - 1950 Specification for Sodium Sulphate, Anhydrous, Technical, or an equivalent grade of the salt of either the anhydrous (Na2SO4) or the crystalline (Na2SO4 10H20) form in water at a temperature of 25o to 30°C. Sufficient salt shall be added to ensure not only saturation but also the presence of excess crystals when the solution is ready for use in the tests. The mixture shall be thoroughly stirred during the addition of the salt and the solution shall be stirred at frequent intervals until used. The solution shall be cooled to a temperature of 27o±2°C and maintained at that temperature for at least 48 hours before use. The solution shall be thoroughly stirred immediately before use and salt cakes, if any, shall be broken and the specific gravity shall be determined. When used, the solution shall have a specific gravity of not less than l.151 and not greater than 1.174. Discolored solution shall be discarded, or filtered and checked for specific gravity. 2. Magnesium Sulphate Solution - The saturated solution of magnesium sulphate shall be made by dissolving magnesium sulphate, technical grade, conforming to IS : 257 - 1950 Specification for Magnesium Sulphate (Epsom Salt ), Technical, or an equivalent grade of the salt of either the anhydrous ( MgSO4 ) or the crystalline ( MgS04.7H2O ) ( epsom salt ) form in water at a temperature of 25° to 30°C. Sufficient quantity of salt shall be added to ensure ‗saturation and the presence of excess crystals when the solution is ready for use in the tests. The mixture shall be thoroughly stirred during the addition of the salt and the solution shall be stirred at frequent intervals until used. The solution shall be cooled to a temperature of 27°± 1°C and maintained at that temperature for at least 48 hours before use. The solution shall be thoroughly stirred immediately before use and salt cakes, if any, shall be broken up and the specific gravity shall be determined. When used, the solution shall have a specific gravity of not less than 1.295 and not more than 1.308. Discolored solution shall be discarded, or filtered and checked for specific gravity.

Procedure

:

1. The sample of coarse aggregate shall be thoroughly washed and dried to constant weight at 105°C to 110°C and shall be separated into different sizes shown in 4.2 by sieving to refusal. The proper weight of sample for each fraction shall be weighed out and placed in separate containers for the test. In the case of fractions coarser than the 20-mm IS Sieve, the number of particles shall also be counted.

2. The samples shall be immersed in the prepared solution of sodium sulphate or magnesium sulphate for not less than 16 hours nor more than 18 hours in such a manner that the solution covers them to a depth of at least 15 mm. The samples immersed in the solution shall be maintained at a temperature of 27°± 1°C for the immersion period.

3. After the immersion period, the aggregate sample shall be removed from the solution, permitted to Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

30

drain for 15 ± 5 minutes, and placed in the drying oven. The temperature of the oven shall have been brought previously to 105‖ to 110°C. During the drying period, the samples shall be removed from the oven, cooled to room temperature and weighed at intervals of not less than 4 hours nor more than 18 hours. Constant weight may be considered to have been achieved when two successive weights for any one sample differ by by less than 1.0 g in the case of coarse aggregate samples.

4. After constant weight has been achieved the samples shall be allowed to cool to room temperature, then they shall again be immersed in the prepared solution as described in step 2.

5. The process of alternate immersion and drying shall be repeated until the specified number of cycles as agreed to between the purchaser and the vendor is obtained.

Observation

Nos of Cycle

: Weight of aggregate

Weight of oven dry aggregate

% weight loss of

before in immersed in the

after in immersed in the

aggregate after

prepared solution

prepared solution

complete of cycle

1 2 3 4 5 6 7 8 9 10 Total Weight loss:

Conclusion / Result

:

As a general guide, it can be taken that the average loss of weight after 10 cycles should not exceed 12 per cent and 18 per cent when tested with sodium sulphate and magnesium sulphate respectively. Given sample of aggregate is sound/unsound

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

31

32

Experiment No.

: 3(e)

Date

Title

: 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

Theory

:

The ‗aggregate crushing value‘ gives a relative measure of the resistance of an aggregate to crushing under a gradually applied compressive load. With aggregate of ‗aggregate crushing value‘ 30 or higher, the result may be anomalous, and in such cases the ‗ten percent fines value‘ should be determined instead.

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

Figure

:

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 Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

not exceed four hours, the temperature shall be 100 to 110°C and the aggregate shall be cooled to 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: B 100 A A  weight in g of saturated surface - dry sample, Aggregate Crushing Value 

B  weight in g of fraction passing through appropriate sievs

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 per cent for concrete used for wearing surfaces such a runways, roads and air field pavements.

Experiment No.

: 3(e)

Title

: Determination of Aggregate Impact Value

Objective

: This method of test covers the procedure for determining the aggregate impact

Date

value of coarse aggregate.

Reference

: IS : 2386 ( Part IV) – 1963, IS: 383-1970

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

33

Theory

34

:

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. 2 and complying with the following:

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

2. A metal 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.

3. 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. Sieves-The IS Sieves of sizes 12.5, 10 and 2.36 mm, Tamping Rod, balance of capacity not less than 500 g, Oven etc.

Figure

:

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 Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

rounded end of the tamping rod. The net weight of aggregate in the measure shall be determined to the nearest 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: B 100 A A  weight in g of saturated surface - dry sample, Aggregate Impact Value 

B  weight in g of fraction passing through 2.36 mm IS Sievs

Conclusion / 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.

Experiment No.

: 3(f)

Title

: Determination of Aggregate Abrasion Value

Objective

: This method of test methods of determining the abrasion value of coarse

Date

aggregate By the use of Los Angeles machine. Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

35

36 Reference

: IS : 2386 ( Part IV) – 1963, IS: 383-1970

Theory

:

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.

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 gradings shown in Table 3.22.

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 Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

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

Figure

:

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 gradings shown in Table 3.22. The grading or gradings 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 gradings A, B, C and D, the machine shall be rotated for 500 revolutions; for gradings E, F and G, it shall be rotated for 1 000 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 l.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.

Department of Civil Engineering

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37

38

B 100 A A  weight in g of saturated surface - dry sample, Aggregate Abrassion Value 

B  weight in g of fraction passing through 1.70 mm IS Sievs

Conclusion / Result

:

The aggregate Abrasion Value of given sample of coarse aggregate is ……….. % The percentage of wear should not be more than 16 per cent for concrete aggregates.

Experiment No.

: 04(a)

Title

: Concrete Mix Design by ACI Committee 211.1 of 1991 Method

Objective

:

Date

To determine the concrete mix proportion by American Concrete Institute Method of Mix Design (ACI Committee 211.1 of 1991) Method.

Reference

:

ACI Committee 211.1 of 1991

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

Theory

39

:

Data to be collected : (i) Fineness modulus of selected F.A. (ii) Unit weight of dry rodded coarse aggregate. (iii) Sp. gravity of coarse and fine aggregates in SSD condition (iv) Absorption characteristics of both coarse and fine aggregates. (v) Specific gravity of cement.

Apparatus

:

(1) Concrete mixer, (2) Balance, (3) Molds (or forms) for casting of the test specimens for future testing.

Procedure

:

1. From the minimum strength specified, estimate the average design strength either by using standard deviation or by using coefficient of variation.

The mean strength, f m  f min  ks

2. Find the water/cement ratio from the strength point of view from Table 11.5. Find also the water/ cement ratio from durability point of view from Table 11.6. Adopt lower value out of strength consideration and durability consideration.

Department of Civil Engineering

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40

3. Decide maximum size of aggregate to be used. Generally for RCC work 20 mm and prestressed concrete 10 mm size are used.

4. Decide workability in terms of slump for the type of job in hand. General guidance can be taken from table 11.7.

5. The total water in kg/m3 of concrete is read from table 11.8 entering the table with the selected slump and selected maximum size of aggregate. Table 11.8 also gives the approximate amount of accidentally entrapped air in non-air-entrained concrete.

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41

6. Cement content is computed by dividing the total water content by the water/cement ratio. The required cement content 

Total Water in kg / m 3 Water / Cement Ratio from Step 2

7. From table 11.4 the bulk volume of dry rodded coarse aggregate per unit volume of concrete is selected, for the particular maximum size of coarse aggregate and fineness modulus of fine aggregate.

8. The weight of C.A. per cubic meter of concrete is calculated by multiplying the bulk volume with bulk density.

Department of Civil Engineering

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Therefore the weight of C.A. in kg / m 3  Dry Bulk Volume of C.A. Per Unit Volume of Concrete (From TAble11.4)



Bulk Density of C.A.

9. From Table 11.9, the first estimate of density of fresh concrete for 20 mm maximum size of aggregate and for non-air-entrained concrete

10. The solid volume of coarse aggregate in one cubic meter of concrete is calculated by knowing the specific gravity of C.A.

11. Similarly the solid volume of cement, water and volume of air is calculated in one cubic meter of concrete.

12. The solid volume of sand is computed by subtracting from the total volume of concrete the solid volume of cement, coarse aggregate, water and entrapped air. Item

Ingredients

Weight

Absolute volume

1

Cement

From Step 6

Weight of Cement 103  Sp. gravity of Cement

2

Water

From Step 5

Weight of Water 103  Sp. gravity of Water

103

3

Coarse Aggregate

From Step 8

Weight of C.A. 103  Sp. gravity of C.A.

103

4

Air

% of Air Voids 10 6  100

103

--Total absolute volume

103

=

13. Wight of fine aggregate is calculated by multiplying the solid volume of fine aggregate by specific gravity of F.A. Absolute volume of F.A.  (1000 - Total Absolute Volume) 103

Weight of F.A.  Aabsolute volume of F.A.  Sp. Gravity of F.A. Department of Civil Engineering

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Result/ Conclusion

43

:

Final Mix Proportion by American Concrete Institute Method of Mix Design (ACI Committee 211.1 of 1991) Method

Ingredients

Cement

Fine Aggregate

Coarse Aggregate

Water

Chemical

Quantity kg / m 3

300.00

870.95

1423.90

135.00

NM

Ratio

1.00

2.90

4.75

0.45

NM

Experiment No.

: 04(b)

Title

: Concrete Mix Design by DOE Method of Concrete Mix Design

Objective

:

Date

To determine the concrete mix proportion by DOE Method of Concrete Mix Design Method.

Reference

:

Theory

:

DOE Method of Concrete Mix Design Method.

The DOE method was first published in 1975 and then revised in 1988. While Road Note No 4 or Grading Curve Method was specifically developed for concrete pavements, the DOE method is applicable to concrete for most purposes, including roads. The method can be used for concrete containing fly ash (in U.K. it is called pulverized fuel ash, PFA) or GGBFS. Since DOE method presently is the standard British method of concrete mix design, the procedure involved in this method is described instead of out dated Road Note No 4 method. Data to be collected : (i) Fineness modulus of selected F.A. (ii) Unit weight of dry rodded coarse aggregate. (iii) Sp. gravity of coarse and fine aggregates in SSD condition (iv) Absorption characteristics of both coarse and fine aggregates. (v) Specific gravity of cement.

Apparatus

:

Department of Civil Engineering

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(1) Concrete mixer, (2) Balance, (3) Molds (or forms) for casting of the test specimens for future testing.

Procedure

:

1. Find the target mean strength from the specified characteristic strength Target mean strength = specified characteristic strength + Standard deviation x risk factor. (Risk factor is on the assumption that 5 percent of results are allowed to fall less than the specified characteristic strength).

The mean strength, f m  f min  ks

2. Step 2: Calculate the water/cement ratio. This is done in a rather round about method, using Table 11.11 and Fig. 11.3.

3. Next decide water content for the required workability, expressed in terms of slump or Vebe time, taking into consideration the size of aggregate and its type from Table 11.12. Department of Civil Engineering

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45

4. Find the cement content knowing the water/cement ratio and water content. Cement content is calculated simply dividing the water content by W/C ratio. The required cement content 

Total Water in kg / m 3 Water / Cement Ratio from Step 2

The cement content so calculated should be compared with the minimum cement content specified from the durability consideration as given in Table 9.20 or Table 9.21 and higher of the two should be adopted. Sometime maximum cement content is also specified. The calculated cement content must be less than the specified maximum cement content.

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5. Next find out the total aggregate content. This requires an estimate of the wet density of the fully compacted concrete. This can be found out from Fig. 11.4 for approximate water content and specific gravity of aggregate. The aggregate content is obtained by subtracting the weight of cement and water content from weight of fresh concrete.

Department of Civil Engineering

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The weight of Total Aggregate in kg / m3  The wet density of Concrete (from Fig) - (Weight of Cement from Step 4  Weight of Water from Step 3)

6. Then, proportion of fine aggregate is determined in the total aggregate using Fig. 11.5. Fig. 11.5(a) is for 10 mm size, 11.5(b) is for 20 mm size and Fig. 11.5(c) is for 40 mm size coarse aggregate. The parameters involved in Fig. 11.5 are maximum size of coarse aggregate, the level of workability, the water/cement ratio, and the percentage of fines passing 600 μ sieves. Once the proportion of F.A. is obtained, multiplying by the weight of total aggregate gives the weight of fine aggregate. Then the weight of the C.A. can be found out. Course aggregate can be further divided into different fractions depending on the shape of aggregate. As a general guidance the figures given in Table 11.14 can be used.

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48

Wight of fine aggregate is calculated by multiplying the solid volume of fine aggregate by specific Department of Civil Engineering

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gravity of F.A. Absolute volume of F.A.  (1000 - Total Absolute Volume) 103

Weight of F.A.  Aabsolute volume of F.A.  Sp. Gravity of F.A. Result/ Conclusion

:

Final Mix Proportion by DOE Method of Concrete Mix Design Method.

Ingredients

Cement

Fine Aggregate

Coarse Aggregate

Water

Chemical

Quantity kg / m 3

300.00

870.95

1423.90

135.00

NM

Ratio

1.00

2.90

4.75

0.45

NM

Experiment No.

: 04(c)

Date

Title

: Concrete Mix Design by Indian standard method IS 10262-2009

Objective

:

To determine the concrete mix proportion by Indian standard Recommended method IS 10262-2009

Reference

:

Theory

:

IS 10262-2009, IS 456 -2000

Data to be collected :

1. Characteristic compressive strength ( that is, below which only a specified proportion of test results are allowed to fall ) of concrete at 28 days (fck)

2. Degree of workability desired 3. Limitations on the water-cement ratio and the minimum cement content to ensure adequate durability 4. Type and maximum size of aggregate to be used 5. Standard deviation (S) of compressive strength of concrete. Apparatus

:

(1) Concrete mixer, (2) Balance, (3) Molds (or forms) for casting of the test specimens for future testing.

Procedure

: Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

1. According to IS: 456–2000 and IS: 1343–‘80, the characteristic strength is defined as that value below which not more than 5 per cent results are expected to fall, in which case the Target mean strength for mix design

The Target Mean Strength, f ck  f ck  1.65  S where f ck  characteristic compressive strength at 28 days. S  is the standard deviation.

Table No. 2 Assumed Standard Deviation

1 2

Nominal Maximum Size of Aggregate M 10 M 15

3 4

M 20 M 25

4.00

5 6 7 8 9 10

M 30 M 35 M 40 M 45 M 50 M 50

5.00

Sr. No.

Assumed Standard Deviation N/mm2 3.50

2. Selection of Water / Content Ratio consider from the specified table (Table-5) of IS: 456 for desired exposure condition as preliminary w/c ratio that has to be further checked for limiting value ensuring durability.

3. Calculation of Water Content. IS: 10262-2009 allows use of water reducers/ super plasticizers and also specifies the alteration in water content accordingly. Further water adjustment was specified in Department of Civil Engineering

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50

terms of variation of compaction factor in the older version whereas the same has been remolded in terms of slump variation (+3% for every 25mm slump over 50mm) in the revised one.

Table No. 2 Maximum Water Content per Cubic Meter of Concrete for Nominal Maximum Size of Aggregate Maximum Water Content Nominal Maximum Size of Sr. No. Aggregate kg / m 3 1

10

208

2

20

189

3

40

165

4. Calculation of Cement Content. The cement content per unit volume of concrete may be calculated from free water-cement ratio and the quantity of water per unit volume of concrete (cement by mass = Water content/Water cement ratio).

Total Water in kg / m 3 The required Cement Content  Water / Cement Ratio from Step 2 The cement content so calculated shall be checked against the minimum cement content for the requirement of durability and the greater of the two values to be adopted.

5. Calculation of Coarse Aggregate Proportion: For the desired workability, the quantity of mixing water per unit volume of concrete and the ratio of coarse aggregate to total aggregate by absolute volume are to be estimated from Tables 3

Table No. 3 Volume of Coarse Aggregate per Unit Volume of Total Aggregate for Different Zones of Fine Aggregate Nominal Size Sr. No. Zone IV Zone III Zone II Zone I of Aggregate 1 10 0.50 0.48 0.46 0.44 2

20

0.66

0.64

0.62

0.60

3

40

0.75

0.73

0.71

0.69

6. Calculation of aggregate content. Aggregate content can be determined from the following equations  C 1 Ca  V  W     SC P S ca   fa 

S fa 1  Ca  1 P S ca

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52 where V  absolute volume of fresh concrete, whic h is equal to gross volume (m3 ) min us the volume of entrapped air, W  Mass of water (kg) per m 3 of concre te C  Mass of cement (kg) per m 3 of concre te S c  Specific gravity of cement P  Ratio of Coarse aggregate to total aggr egate by a bsolute volume f a, C a  Total masses of FA and CA (kg) per m 3 of concre te respect ively and S fa , S ca  Specific gravities of saturated, surface dry fine aggregate and coarse aggregate respectively.

7. Combination of Different Coarse Aggregate Fractions: The coarse aggregate used shall conform to IS 383 – 1970. Coarse aggregate of different sizes may be combined in suitable proportions so as result in an overall grading conforming to Table 2 of IS 383 – 1970 for nominal maximum size of aggregate.

Result/ Conclusion

:

Final Mix Proportion by American Concrete Institute Method of Mix Design (ACI Committee 211.1 of 1991) Method

Ingredients

Cement

Fine Aggregate

Coarse Aggregate

Water

Chemical

Quantity kg / m 3

300.00

870.95

1423.90

135.00

NM

Ratio

1.00

2.90

4.75

0.45

NM

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

53 Experiment No.

: 05(a)

Title

: Making and Curing Concrete Test Specimens in the Laboratory

Objective

:

Date

This practice cover procedures for making and curing test specimens of concrete in the laboratory under accurate control of materials and test conditions using concrete that can be consolidated by rodding or vibration .

Reference

:

Procedure

:

IS 456 : 2000, SP : 23-1982, IS: 1199-1959

Weighing:

1. 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 Procedure for mixing Concrete : Machine Mixing:

1. Put the coarse aggregate in the mixer, add some of the mixing water and the solution of admixture, when required, [add with water].

2. Start the mixer, then add the fine aggregate, cement and water with the mixer running .If it is impractical to add the fine aggregate, cement and water with the mixer is running, these components may be added to the stopped mixer after permitting it to turn a few revolutions following charging with coarse aggregate and some of the water.

3. Mix the concrete, after all integrates are in the mixer, for 3 minutes followed by 3 minutes rest, following by 2-minutes final mixing. Hand Mixing:-

1. The cement and fine aggregate shall be mixed dry until the mixture is thoroughly blended and is uniform in colour,

2. The coarse aggregate shall then be added and mixed with the cement and fine aggregate until the coarse aggregate is uniformly distributed throughout the batch, and

3. The water shall then be added and the entire batch mixed until the concrete appears to be homogeneous and has the desired consistency.

4. If repeated mixing is necessary, because of the addition of water in increments while adjusting the consistency, the batch shall be discarded and a fresh batch made without interrupting the mixing to Department of Civil Engineering

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make trial consistency tests. Making Specimens: Place of Molding:

1. Mold specimens as near as practicable to the place where they are to be stored during the first 24 hours.

2. Place molds on a rigid surface free from vibration and other disturbances 3. If it is not practicable to mold the specimens where they will be stored, move them to the place of storage immediately after being struck off. Placing:

1. Place the concrete in the molds using a scoop, blunted trowel, or shovel. Select each scoopful, trowelful, or shovelful of concrete from the mixing pan to ensure that it is representative of the batch.

2. It may be necessary to remix the concrete in the mixing pan with a shovel to prevent segregation during the molding of specimens.

3. Move the scoop or trowel a round the top edge of the mold as the concrete is discharged in order to ensure symmetrical distribution of the concrete and for minimize segregation of coarse aggregate within the mold.

4. Further distribute the concrete by use of a tamping rod prior to the start of consolidation. Methods of consolidation : Preparation of satisfactory specimens requires different methods of consolidation. The methods of consolidation are: a) Rodding, b) Internal vibration, c) External vibration. Rodding:

1. Place the concrete in the mold in the required number of layers of approximately equal volume .Rod each layer with the rounded end of the rod using the number of strokes.

2. Rod the bottom layer throughout its depth. Distribute the strokes uniformly over the cross-section of the mold and for each upper layer allow the rod to penetrate about 12mm into the underlying layer when the depth of the layer is less than 100mm and about (25mm) when the depth is (100mm) or more.

3. After each layer is rodded, tap the outside of the mold lightly 10-15 times with the mallet to close any holes left by rodding. Vibration:

1. The duration of vibration required will depend upon the workability of the concrete and the effectiveness of the vibrator. Continue vibration only long enough to achieve proper consolidation of the concrete.

2. Fill the molds and vibrate in the required number of approximately equal layers. Place all the concrete for each layer in the mold before starting vibration of that layer. Department of Civil Engineering

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3. Add the final layer, so as to avoid over filling by more than (6 mm). Then finish the surface. Finishing: After consolidation, strike off the surface of the concrete and float or trowel it with a wood or magnesium float. Curing:

1. 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.

2. After this period, the specimens shall be marked and removed from the moulds and, unless required for test within 24 hours, immediately submerged in clean, fresh water or saturated lime solution and kept there until taken out just prior to test.

3. The water or solution in which the specimens are submerged shall be renewed every seven days and shall be maintained at a temperature of 27° ± 2°C. The specimens shall not be allowed to become dry at any time until they have been tested.

Experiment No.

:

05(b)

Date

Title

:

Determination Workability of Fresh Concrete By Slump Cone Test

Objective

:

To determine the relative consistency of freshly mixed concrete by the use of Slump Test.

Reference

:

IS: 7320-1974, IS: 1199-1959, SP : 23-1982

Theory

:

The word ―workability‖ or workable concrete signifies much wider and deeper meaning than the other terminology ―consistency‖ often used loosely for workability. Consistency is a general term to indicate the degree of fluidity or the degree of mobility. The factors helping concrete to have more lubricating effect to reduce internal friction for helping easy compaction are given below: (a) Water Content (b) Mix Proportions (c) Size of Aggregates (d) Shape of Aggregates (e) Surface Texture of Aggregate (f) Grading of Aggregate (g) Use of Admixtures. Measurement of Workability The following tests are commonly employed to measure workability. Department of Civil Engineering

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(a) Slump Test (b) Compacting Factor Test (c) Flow Test (d) Kelly Ball Test (e) Vee Bee Consistometer Test. Slump Test: Slump test is the most commonly used method of measuring consistency of concrete which can be employed either in laboratory or at site of work. It is not a suitable method for very wet or very dry concrete. It does not measure all factors contributing to workability, nor is it always representative of the placability of the concrete. The pattern of slump is shown in Fig. It indicates the characteristic of concrete in addition to the slump value. If the concrete slumps evenly it is called true slump. If one half of the cone slides down, it is called shear slump. In case of a shear slump, the slump value is measured as the difference in height between the height of the mould and the average value of the subsidence.

Apparatus

:

The Slump Cone apparatus for conducting the slump test essentially consists of a metallic mould in the form of a frustum of a cone having the internal dimensions as under: Bottom diameter : 20 cm, Top diameter : 10 cm, Height : 30 cm and the thickness of the metallic sheet for the mould should not be thinner than 1.6 mm Weights and weighing device, Tamper ( 16 mm in diameter and 600 mm length), Ruler, Tools and containers for mixing, or concrete mixer etc.

Procedure

:

1. Dampen the mold and place it on a flat, moist, nonabsorbent (rigid) surface. It shall be held firmly in place during filling by the operator standing on the two foot pieces. Immediately fill the mold in three layers, each approximately one third the volume of the mold.

2. Rod each layer with 25 strokes of the tamping rod. Uniformly distribute the strokes over the cross section of each layer.

3. In filling and rodding the top layer, heap the concrete above the mold before rodding start. If the rodding operation results in subsidence of the concrete below the top edge of the mold, add additional concrete to keep an excess of concrete above the top of the mold at all time.

4. After the top layer has been rodded, strike off the surface of the concrete by means of screeding and rolling motion of the tamping rod.

5. Remove the mold immediately from the concrete by raising it carefully in the vertical direction. Raise the mold a distance of 300 mm in 5 ± 2 sec by a steady upward lift with no lateral or torsional motion.

6. Immediately measure the slump by determining the vertical difference between top of the mold and the displaces original center of the top surface of the specimen. Complete the entire test from the start Department of Civil Engineering

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of the filling through removal of the mold without interruption and complete it within 2½ min.

7. If a decided falling away or shearing off of concrete from one side or portion of the mass occurs, disregard the test and make a new test on another portion of the sample. If two consecutive tests on a sample of concrete show a falling away or shearing off of a portion of concrete from the mass of specimen, the concrete lacks necessary plasticity and cohesiveness for the slump test to be applicable.

8. After completion of the test, the sample may be used for casting of the specimens for the future testing. Figure

:

Observation

:

1. The vertical difference between top of the mold and the displaces original center of the top surface of the specimen ………… mm Department of Civil Engineering

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2. The pattern of slump is shown True Slump/Shear Slump/ Collapse Slump. Conclusion / R

:

The slump of concrete ……….. mm indicate Low/ Medium/ High Degree of workability

Experiment No.

:

05(c)

Date

Title

:

Determination Workability of Fresh Concrete By Compacting Factor Test

Objective

:

To determine the relative consistency of freshly mixed concrete by the use of Compacting Factor Test

Reference

:

IS; 1199-1959, SP : 23-1982

Theory

:

Compacting Factor Test: The compacting factor test is designed primarily for use in the laboratory but it can also be used in the field. It is more precise and sensitive than the slump test and is particularly useful for concrete mixes of very low workability as are normally used when concrete is to be compacted by vibration. The method applies to plain and air-entrained concrete, made with lightweight, normal weight or heavy aggregates having a nominal maximum size of 40 mm or less but not to aerated concrete or no-fines concrete.

Apparatus

:

Compacting Factor Apparatus, Trowel, Scoop about 150 mm long., Balance capable of weighing up to 25 kg with the sensibility of 10 g. Weights and weighing device, Tamper ( 16 mm in diameter and 600 mm length), Ruler, Tools and containers for mixing, or concrete mixer etc.

Procedure

:

1. The internal surface of the hoppers and cylinder shall be thoroughly clean and free from superfluous moisture and any set of concrete commencing the test.

2. The sample of concrete to be tested shall be placed gently in the upper hopper using the scoop. The trap door shall be opened immediately after filling or approximately 6 min after water is added so that the concrete fails into the lower hopper. During this process the cylinder shall be covered.

3. Immediately after the concrete has come to the rest the cylinder shall be uncovered, the trap door of Department of Civil Engineering

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the lower hopper opened and the concrete allowed falling to into the cylinder.

4. For some mixes have a tendency to stick in one or both of the hoppers. If this occurs the concrete shall be helped through by pushing the tamping rod gently into the concrete from the top.

5. The excess of concrete remaining above the level of the top of the cylinder shall then be cut off by holding a trowel in each hand, with the plane of the blades horizontal, and moving them simultaneously one from each side across the top of the cylinder, at the same time keeping them pressed on the top edge of the cylinder. The outside of the cylinder shall then be wiped clean. This entire process shall be carried out at a place free from vibration or shock.

6. Determine the weight of concrete to the nearest 10 g. This is known as "weight of partially compacted concrete", Wp.

7. Refill the cylinder with concrete from the same sample in layers approximately 50 mm depth. The layers being heavily rammed with the compacting rod or vibrated to obtain full compaction. The top surface of the fully compacted concrete shall be carefully struck off and finished level with the top of the cylinder. Clean up the outside of the cylinder.

8. Determine the weight of concrete to the nearest 10 g. This is known as "weight of fully compacted concrete", Wf.

9. The compacting factor, Fc can be calculated as follows: The compacting factor 

Figure

" weight of partially compacted concrete" , Wp . " weight of fully compacted concrete" , Wf .

:

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59

Observation

60

:

The compacting factor is defined as the ratio of the weight of partially compacted concrete to the weight of fully compacted concrete. It shall normally be stated to the nearest second decimal place. Sr.

Description

No

Sample 1

1.

Weight of Empty Cylinder (W1)

2.

Weight of Cylinder + Free Fall Concrete (W2)

3.

Weight of Cylinder + Hand Compacted Concrete (W2)

4.

Weight of Partially Compacted Concrete (Wp=W2-W1)

5.

Weight of Fully Compacted Concrete (Wf=W2-W1)

6

The Compacting Factor =Wp/Wf

Sample 2

Conclusion

:

Experiment No.

:

05(d)

Title

:

Determination of Consistency of Concrete by Vee-Bee

Sample 3

Date

Consistometer Method Objective

:

The determination of consistency of concrete using a Vee-Bee Consistometer, which determines the time required for transforming, by vibration, a concrete specimen in the shape of a conical frustum into a cylinder.

Reference

:

Theory

:

IS: 7320-1974, IS: 1199-1959, SP : 23-1982

Vee Bee Consistometer Test: This is a good laboratory test to measure indirectly the workability of concrete. This test consists of a vibrating table, a metal pot, a sheet metal cone, a standard iron rod. The vibrator table (C) is 380 mm long and 260 mm wide and is supported on rubber shock absorbers at a height of about 305 mm above floor level. The table is mounted on a base (K) which rests on three rubber feet and is equipped with an electrically operated vibrometer mounted under it, operating on either 65 or 220 volts three phase, 50 cycles alternating current. A sheet metal cone (B) open at both ends is placed in the metal pot (A) and the metal pot is fixed on to the vibrator table by means of two wing-nuts (H). The Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

sheet metal cone is 30 cm high and its bottom diameter is 20 cm and top diameter 10 cm. A swivel arm holder (M) is fixed to the base and, into this is telescoped another swivel arm (N) with funnel (D) and guide-sleeve (E). The swivel arm can be readily detached from the vibrator table. The graduated rod (J) is fixed on to the swivel arm and at the end of the graduated arm ‗8. glass disc records the slump of concrete after rod is 20 mm in (C) is screwed. The division of the scale on the rod bf the concrete cone in centimetres and the volume vibration of the cone in the pot. The standard iron diameter and 500 mm in length.

Apparatus

:

Vee Bee Consistometer : a) A vibrator table resting upon elastic supports, b) A metal pot, c) A sheet metal cone, open at both ends, and d) A standard iron rod. Weights and weighing device, Tamper ( 16 mm in diameter and 600 mm length), Ruler, Tools and containers for mixing, or concrete mixer etc.

Procedure

:

1. Slump test as described earlier is performed, placing the slump cone inside the sheet metal cylindrical pot of the consistometer.

2. The glass disc attached to the swivel arm is turned and placed on the top of the concrete in the pot. The electrical vibrator is then switched on and simultaneously a stop watch started.

3. The vibration is continued till such a time as the conical shape of the concrete disappears and the concrete assumes a cylindrical shape. This can be judged by observing the glass disc from the top for disappearance of transparency.

4. Immediately when the concrete fully assumes a cylindrical shape, the stop watch is switched off. The time required for the shape of concrete to change from slump cone shape to cylindrical shape in seconds is known as Vee Bee Degree.

5. This method is very suitable for very dry concrete whose slump value cannot be measured by Slump Test, but the vibration is too vigorous for concrete with a slump greater than about 50 mm. Figure

:

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61

62

Observation

:

1. The time required for the shape of concrete to change from slump cone shape to cylindrical shape in seconds is known as Vee Bee Degree

Conclusion / R

:

The Vee Bee Degre of concrete ……….. sec indicate Low/ Medium/ High Degree of workability

Experiment No.

:

05(e)

Date

Title

:

Determine Compressive Strength of Cubic Concrete Specimens

Objective

:

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

:

Theory

:

IS : 516 - 1959, IS: 1199-1959, SP : 23-1982, IS : 10086-1982

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 ± Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

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

:

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. Cube Moulds - The mould shall be of 150 mm size conforming to IS: 10086-1982. Cylinders -The cylindrical mould shall be of 150 mm diameter and 300 mm height conforming to IS: 10086-1982. Weights and weighing device, Tools and containers for mixing, Tamper (square in cross section) 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.

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. Department of Civil Engineering

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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. Figure

:

Observation

:

Data for the calculating of the mix proportion Sr. No.

Description

1

Compressive strength at 28 days

2

Slump

3

Type of cement

4

Specific gravity of cement

Value

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

64

65

5

Type of sand

6

Specific gravity of sand

7

Fineness modulus

8

Type of coarse aggregate

Calculations of Mix Proportion Mix proportion of concrete

For 1 cubic meter of concrete

For one batch of mixing

Coarse aggregate (kg) Fine aggregate (kg) Cement (kg) Water (kg) S/A w/c Admixture

Sr. No.

Age of Cube

Weight of Cement Cube (gms)

CrossSectional area (mm2)

Load (N)

Compressive strength (N/mm2)

Average Compressive strength (MPa)

1 2

7 Days

3 4 5

28 Days

`

6

Conclusion / R

:

i) The average 7 Days Compressive Strength of concrete sample is found to be …..….. ii) The average 28 Days Compressive Strength of concrete sample is found to be …..…..

Experiment No.

:

05(f)

Date

Title

:

Determine Flexural Strength of Cubic Concrete Specimens

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

Objective

:

This clause deals with the procedure for determining the flexural strength of moulded concrete flexure test specimens

Reference

:

Theory

:

IS : 516 - 1959, IS: 1199-1959, SP : 23-1982, IS : 10086-1982

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

:

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. 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. Weights and weighing device, Tools and containers for mixing, Tamper (square in cross section) 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. Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

66

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.

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 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. Figure

:

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

67

Observation

68

:

Calculations of Mix Proportion Mix proportion of concrete

For 1 cubic meter of concrete

For one batch of mixing

Coarse aggregate (kg) Fine aggregate (kg) Cement (kg) Water (kg) S/A w/c Admixture

Sr. No.

Age of Specimen

Identification Mark

Size of Specimen (mm)

Span Length (mm)

Maximum Load (N)

Position of Fracture ‗a‘ (mm)

Modulus of Rupture (MPa)

1 2

7 Days

3 4 5

28 Days

`

6

Calculation

:

The flexural strength of the specimen shall be expressed as the modulus of rupture fb, which, if ‗a‘ equals the distance between the line of fracture and the nearer support, measured on the centre line of the tensile side of the specimen, in cm, shall be calculated to the nearest 0.5 kg/sq cm as follows:

fb 

Pl ad2

when ‗a‘ is greater than 20.0 cm for 15.0 cm specimen, or greater than 13.3 cm for a 10.0 cm specimen, or

fb 

3P  a bd 2

when ‗a‘ is less than 20.0 cm but greater than 17.0 cm for 15.0 cm specimen, or less than 13.3 cm but greater than 11.0 cm for a 10.0 cm specimen

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

69

where b = measured width in cm of the specimen, d = measured depth in cm of the specimen at the point of failure, l = length in cm of the span on which the specimen was supported,and p = maximum load in kg applied to the specimen.

Conclusion / R

:

i) The average 7 Days Modulus of Rupture of concrete sample is found to be …..….. ii) The average 28 Days Modulus of Rupture of concrete sample is found to be …..…..

Experiment No.

:

05(g)

Date

Title

:

Determine Splitting Tensile Strength of Cylindrical Concrete Specimens

Objective

:

This method covers the determination of the splitting tensile strength of cylindrical concrete specimens.

Reference

:

Theory

:

IS : 516 - 1959, IS: 1199-1959, SP : 23-1982, IS : 10086-1982

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

:

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. Cylinders -The cylindrical mould shall be of 150 mm diameter and 300 mm height conforming to IS: 10086-1982. Weights and weighing device, Tools and containers for mixing, Tamper (square in cross section) etc. Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

70 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.

5. Mould - The cylindrical mould shall be of 150 mm diameter and 300 mm height conforming to IS: 10086-1982.

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 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 Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

the cylinder. 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

14. Record the maximum applied load indicated by the testing machine at failure. Note the typeof failure and appearance of fracture. Figure

:

Observation

:

Calculations of Mix Proportion Mix proportion of concrete

For 1 cubic meter of concrete

For one batch of mixing

Coarse aggregate (kg) Fine aggregate (kg) Cement (kg) Water (kg) S/A w/c Admixture

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

71

Sr. No.

Age of Specimen

Identification Mark

Dia of Specimen (mm)

Depth (mm)

Maximum Load (N)

Tensile Strength (MPa)

Average Tensile Strength (MPa)

1 2

7 Days

3 4 5

28 Days

`

6

Calculation

:

Calculate the splitting tensile strength of the specimen as follows:

T

2P Ld

where T : splitting tensile strength, kPa P : maximum applied load indicated by testingmachine, kN L : Length, m d : diameter

Conclusion / R

:

i) The average 7 Days Tensile Strength of concrete sample is found to be …..….. ii) The average 28 Days Tensile Strength of concrete sample is found to be …..…..

Department of Civil Engineering

Sanjay Ghodawat Group of Institutions, Atigre, Kolhapur

72