Concrete Technology Lab Manual PDF

NATIONAL INSTITUTE OF TECHNOLOGY WARANGAL DEPARTMENT OF CIVIL ENGINEERING CONCRETE TECHNOLOGY LAB MANUAL II B.Tech. I Semester CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL...

NATIONAL INSTITUTE OF TECHNOLOGY WARANGAL DEPARTMENT OF CIVIL ENGINEERING CONCRETE TECHNOLOGY LAB MANUAL II B.Tech. I Semester CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 1  EXPERIMENT NO: 1 (a) FINENESS OF CEMENT BY DRY SIEVING OBJECT: To determine fineness of given cement by dry sieving 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. 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 and is expressed as cm2/g or m2/kg. Generally Blaine Air permeability apparatus is used. APPARATUS: Test Sieve 90 microns, Balance, Gauging Trowel, Brush. PROCEDURE: 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 carefully to avoid loss. Fit the lid over the sieve and agitate until most of the material passes through it. 2. Remove and weigh the residue. Express its mass as a percentage, R 1, 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 R 2. 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. RESULT: The fineness of given sample of Cement is _________ % REFERRED INDIAN STANDARD CODES: 1. IS 4031 (Part I): 1996 (Reaffirmed 2005) - Indian Standard Method of Physical Tests for Hydraulic Cement – Determination of fineness by dry sieving. CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 2  EXPERIMENT NO: 1(b) SPECIFIC GRAVITY OF CEMENT OBJECT: To determine specific gravity of cement THEORY: Specific gravity of cement is normally defined as the ratio between the weight of a given volume of material and weight of a equal volume of water.the one method of determining the specific gravity of cement is by the use of a liquid such as water-free kerosene which does not react with cement. For an Ordinary Portland Cement the specific gravity is 3.15. APPARATUS: Physical balance, specific gravity bottle, kerosene PROCEDURE: 1. Weigh the specific gravity of dry bottle (W1) 2. Fill the bottle with distilled water and weigh the bottle filled with water, (W 2) 3. Wipe dry the specific gravity bottle and fill it with kerosene weight (W3) 4. Pour some of the kerosene out and introduce a weighted quantity of 10 grams of cement into the bottle. 5. Roll the bottle gently in inclined position until no further air bubble rises to surface. Fill the bottle to the top with kerosene and weigh it (W4). OBSERVATIONS AND CALCULATIONS: Sl. No Description Trial – 1 Trail – 2 Trial - 3 1. Wt. of empty bottle (W1) 2. Wt. of bottle + Water (W2) 3. Wt. of bottle + Kerosene (W3) 4. Wt. of bottle + Kerosene + Cement (W4) 5. Wt. of Cement (W5) 6. Specific Gravity of Kerosene 7. Specific Gravity of Cement W3 − W1 Specific Gravity of Kerosene = Sk = W2 − W1 W5  S k Specific Gravity of Cement = Sc = W5 + W3 − W4 RESULT: The Specific Gravity of Cement is _________________ CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 3 PRECAUTIONS: 1 The kerosene used should be free from water. 2 While introducing cement, care should be taken to avoid splashing and cement should not adhere to the inside of the flask above the liquid. REFERED INDIAN STANDARD CODES: 1. IS 2720 Part -3 –1980 (Reaffirmed 2002) Methods of tests for soil – Determination of Specific gravity CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 4  EXPERIMENT No - 2 CONSISTENCY OF STANDARD CEMENT PASTE OBJECT: This method of test covers the procedure for determining the quantity of water required to produce a cement paste of standard consistency. THEORY: The object of conducting this test is to find out the amount of water to be added to the cement to get a paste of normal consistency i.e. a paste of certain standard solidity which is used to fix the quantity of water to be added in cement before performing test for compressive strength, setting time and soundness. APPARATUS: Vicat apparatus with Vicat plunger, mould, gauging trowel, 100ml-measuring jar, weighing balance, stopwatch, china dish. DESCRIPTION OF APPARATUS: The Vicat apparatus consists of a frame bearing a movable rod with, at one end, the cap and at the other, one of the following, which is removable. The needle for determining the initial setting time (1mm square in section or of 1.13mm diameter), the needle for determining final setting time (which has the same shape and section of initial setting needle but shall be fitted with a metal attachment hollowed out so as to leave a circular cutting edge 5mm this edge), or the plunger shall be of polished brass 10mm in diameter for determining the normal consistency. The movable rod carries an indicator, which moves over a graduated scale. With all attachments the cap and rod with initial setting, needle or final setting needle or plunger shall together weight 300gms. The mould for cement consists of a split ring of 80mm in diameter 40mm in height, which rests on a non-porous plate. PROCEDURE: The consistency of standard cement paste is defined as that consistency which will permit the Vicat plunger to penetrate to a point 5 to 7mm from the bottom of the Vicat mould when the cement paste is tested as follows: 1. For preparing one mould take 400 gms of cement and prepare a paste of cement with a weighted (measured) quantity of water, taking care that the time of gauging is not less than 3min, nor more than 5min, and the gauging shall be completed before any signs of setting occur. The gauging time shall be counted from the time of adding water to the dry cement until commencing to fill the mould. CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 5  2. Fill the vicat mould with this pate resting on a non-porous pate. After completely filling the mould, smooth off the top of the mould. The mould may be slightly shaken to expel the air. 3. 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 rest block, and quickly release, allowing it to sink into the paste. This operation shall be carried out immediately after filling the mould. 4. Prepare trail test pastes with varying percentages of water (26,28,30,33%) and test until the amount of water necessary for making up the standard consistency as defined is found. Express the amount of water as a percentage by weight of the dry cement. OBSERVATIONS AND CALCULATIONS: Sl. % Water Volume of water Gauging time Reading of Vicat’s No. added (ml) (Sec) Apparatus RESULT: The Consistency of standard cement paste is ______________ PRECAUTIONS: 1. From the instant of adding water into the cement, it should be thoroughly mixed. 2. The consistency plunger should be released immediately on the paste with out pressure and jerk after the rod is brought down to touch the surface of the test block. 3. For each repetition of the experiment fresh cement is to be taken. 4. Plunger should cleaned during every repetition and make sure that it moves freely. REFERED INDIAN STANDARD CODES: 1. IS 4031 (Part – 4) – 1988 (Reaffirmed 1995) – Methods of Physical tests for Hydraulic Cement – Determination of Consistency of Standard Cement Paste. 2. IS 5513– 1996 (Reaffirmed 2005) – Specifications for Vicat’s Apparatus. CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 6  EXPERIMENT No – 3 INITIAL AND FINAL SETTING TIME OF CEMENT OBJECT: This method of test covers the procedure for determining the initial and final setting time of cement. THEORY: In order that the concrete may be placed in position conveniently, it is necessary that initial setting time of cement is not too quick (i.e., not less than 30 minutes). Once the concrete is transported, placed, compacted and finished, it shall set early; it is necessary that the final setting time shall not be too late (i.e., not more than 600 minutes). APPARATUS: Vicat apparatus with initial and final setting needles, measuring jar of 100 cc, stopwatch, china dish, trowels. PROCEDURE: 1. Take 400 gm. of cement. 2. Prepare a neat cement paste by gauging the cement with 0.85 times the water required to give a paste of standard consistency (i.e., 0.85P) 3. Start a stopwatch at the instant when water is added to the cement. 4. Fill the vicat mould with 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. The cement block thus prepared in the mould is the test block. PART A - DETERMINATION OF INITIAL SETTING TIME: 1. Place the block confined in the mould and resting on the non-porous plate under the vicat rod bearing initial setting needle. 2. Lower the setting needle gently in contact with the surface of the test block and quickly release allowing it to penetrate into test block. 3. In the beginning the needle will completely pierce the test block. Repeat this procedure until the needle, when brought in contact with the test block and released as described above, fails to pierce the block for about 5mm measured from the bottom of the mould. 4. The period elapsing between the time when water is added to the cement and the time at which the needle fails to pierce the test block by about 5mm shall be the initial setting time. CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 7 OBSERVATIONS AND CALCULATIONS: Time %of water Volume of Reading on Vicat Total time (min) added water (cc) apparatus (mm) taken (min) 0 0.85 P RESULT: The Initial Setting Time of given sample of Cement is ____________ PART B - DETERMINATION OF FINAL SETTING TIME: 1. Replace the initial setting needle of the Vicat apparatus by the needle with an annular attachment. 2. The cement shall be considered as finally set, when upon applying the needle gently to the surface of the test block, the needle makes an impression there on, while the annular attachment fails to do so. RESULT: The Final Setting Time of given sample of Cement is ____________ REFERED INDIAN STANDARD CODES: 3. IS 4031 (Part – 5) – 1988 (Reaffirmed 2000)– Methods of Physical tests for Hydraulic Cement – Determination of Initial and Final Setting times. 4. IS 5513– 1996 (Reaffirmed 2005) – Specifications for Vicat’s Apparatus. 5. IS 269 – 2013 – Ordinary Portland Cement, 33 Grade – Specification 6. IS 8112 – 2013 – 43 Grade Ordinary Portland Cement – Specification 7. IS 12269 – 2013 – Specifications for 53 Grade Ordinary Portland Cement CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 8  EXPERIMENT NO: 4 COMPRESSIVE STRENGTH OF CEMENT OBJECT: To determine the compressive strength of a given sample of cement APPARATUS: Vibration Machine, Poking Rod, Cube Mould of 70.6 mm side (50 sq.cm), Balance, Gauging Trowel, Stop Watch, Graduated Glass Cylinders. THEORY: 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 based on cement mortar in 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. 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: Cement 200 g and Standard Sand 600 g, Water (P/4 + 3) percent of combined mass of cement and sand, where P is the percentage of water required to produce a paste of standard consistency determined as described in IS : 4031 (Part 4)-1988. 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. 6. Immediately after mixing the mortar in accordance with steps 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. CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 9  7. The period of vibration shall be two minutes at the specified speed of 12000 ± 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 smoothening 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 for curing. 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/mm 2 /min. OBSERVATIONS AND CALCULATIONS: S.No. Curing Weight of Load Compressive Average Period cement (kN) Strength Compressive cube (g) (MPa) Strength (MPa) 1 2 7 Days 3 4 28 5 Days 6 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. RESULT: 1. The average 7 Days Compressive Strength of given cement sample is ____ 2. The average 28 Days Compressive Strength of given cement sample is …..….. CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 10 REFERRED INDIAN STANDARD CODES: 1. IS 4031 (Part – VI) – 1988 (Reaffirmed 2005) Indian Standard Methods of Physical tests for Hydraulic cement – Compressive Strength of Cement. 2. IS 650 – 1991 ( Reaffirmed 2008) Standard Sand for Testing Cement – Specification 3. IS 12269 – 1987 (Reaffirmed 2004) – Indian Standard Specification for 53 Grade Ordinary Portland Cement CONCRETE TECHNOLOGY LABORATORY, CED, N I T WARANGAL 11