Various Laboratory Tests on Cement

VARIOUS LAB tribulation ON cementumum Checking of materials is an essential part of civil engineering as the life of structure is dependent on the quality of material used. by-line are the tests to be conducted to judge the quality of cement. 1. Fineness 2. Soundness 3. amity 4. Initial and Final linguistic context Time of cementum FINENESS OF CEMENT We film to interpret the fineness of cement by dry sieving as per IS 4031 (Part 1) 1996. The principle of this is that we set up the proportion of cement whose grain size is big than specified mesh size. apparatus The tool used are ) 75m IS Sieve ii) Balance capable of weighing 10g to the nearest 10mg iii) A nylon or pure bristle brush, preferably with 25 to 40mm iv) bristle, for cleaning the filtrate Figure No. Sieve No. 200 Procedure to determine fineness of cement i) Weigh approximately 10g of cement to the nearest 0. 01g and distinguish it on the sieve. ii) Agitate the sieve by swirling, planetary and linear movement s, until no more fine material passes through it. iii) Weigh the residue and present its mass as a percentage R1,of the quantity first fit(p) on the sieve to the nearest 0. 1 percent. v) Gently brush every(prenominal) the fine material mutilate the base of the sieve. v) twin the unit subroutine using a fresh 10g sample to obtain R2. Then imagine R as the mean of R1 and R2 as a percentage, expressed to the nearest 0. 1 percent. When the results differ by more than 1 percent absolute, play out a third sieving and calculate the mean of the three values. inform of Results Report the value of R, to the nearest 0. 1 percent, as the residue on the 90m sieve. Test To Check Soundness Of Cement resolution Soundness of cement is determined by Le-Chatelier method as per IS 4031 (Part 3) 1988.Apparatus The apparatus for conducting the Le-Chatelier test should conform to IS 5514 1969 Balance, whose permissible variation at a elongate of 1000g should be +1. 0g and Water bath. Proced ure to determine soundness of cement i) lay the lick on a glass sheet and fill it with the cement cattle farm formed by gauging cement with 0. 78 magazines the wet required to give a bed cover of standard organic structure. ii) Cover the turn with another piece of glass sheet, place a small pack on this covering glass sheet and immediately submerge the whole assembly in pissing at a temperature of 27 2oC and lionize it there for 24hrs. ii) Measure the outdistance separating the indicator points to the nearest 0. 5mm (say d1 ). iv) Submerge the mould again in pee at the temperature prescribed above. Bring the pee to boiling point in 25 to 30 minutes and apply it boiling for 3hrs. v) Remove the mould from the water, allow it to cool and measure the distance amongst the indicator points (say d2 ). vi) (d2 d1 ) represents the expansion of cement. Test To Check Consistency Of Cement CONSISTENCY The basic aim is to find out the water pith required to produce a cement p aste of standard consistency as specified by the IS 4031 (Part 4) 1988.The principle is that standard consistency of cement is that consistency at which the Vicat plunger penetrates to a point 5-7mm from the bottom of Vicat mould. Apparatus Vicat apparatus conforming to IS 5513 1976, Balance, whose permissible variation at a lade of 1000g should be +1. 0g, Gauging trowel conforming to IS 10086 1982. Procedure to determine consistency of cement i) Weigh approximately 400g of cement and mix it with a weighed quantity of water. The time of gauging should be between 3 to 5 minutes. ii) Fill the Vicat mould with paste and level it with a trowel. ii) Lower the plunger gently till it touches the cement surface. iv) Release the plunger allowing it to sink into the paste. v) Note the reading on the gauge. vi) reduplicate the above procedure taking fresh samples of cement and different quantities of water until the reading on the gauge is 5 to 7mm. Reporting of Results Express the add of water as a percentage of the weight of dry cement to the first place of decimal. Test To Check Initial And Final Setting Time Of Cement INITIAL AND terminal condition TIME We need to calculate the initial and last setting time as per IS 4031 (Part 5) 1988.To do so we need Vicat apparatus conforming to IS 5513 1976, Balance, whose permissible variation at a load of 1000g should be +1. 0g, Gauging trowel conforming to IS 10086 1982. Procedure to determine initial and final setting time of cement i) Prepare a cement paste by gauging the cement with 0. 85 times the water required to give a paste of standard consistency. ii) Start a stop-watch, the moment water is added to the cement. iii) Fill the Vicat mould completely with the cement paste gauged as above, the mould resting on a non-porous plate and smooth off the surface of the paste making it level with the top of the mould.The cement frustrate thus prepared in the mould is the test block. A)INITIAL SETTING TIME Place the test block under the rod kick the chivy. Lower the needle gently in order to make edge with the surface of the cement paste and release quickly, allowing it to penetrate the test block. Repeat the procedure till the needle fails to pierce the test block to a point 5. 0 0. 5mm measured from the bottom of the mould. The time period elapsing between the time, water is added to the cement and the time, the needle fails to pierce the test block by 5. 0 0. mm measured from the bottom of the mould, is the initial setting time. B)FINAL SETTING TIME Replace the above needle by the wiz with an annular appendage. The cement should be considered as finally set when, upon applying the needle gently to the surface of the test block, the needle makes an burden therein, while the attachment fails to do so. The period elapsing between the time, water is added to the cement and the time, the needle makes an impression on the surface of the test block, while the attachment fails to do so, is the final setting time.