What Is Consistency of Cement?
Any Cement paste requirement of minimum water in cement paste for initiate the chemical reaction. This chemical reaction call the consistency of cement. This method call consistency fo cement test.
Relevant is code: IS code 4031 part 4 -Consistency of Standard Cement past
What is Initial Setting time of Cement?
Initial setting time of cement: Casting cement past in any mold without losing strength & Shape. This working prosses time call initial setting time of cement.
Also Read : CORE CUTTER METHOD
Determination of Initial Setting Time: from IS Code 4031 part 5, page no 2, cl 5.2
Place the test block confined in the mold 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 text block and quickly releases. From IS Code 4031 part 5
Allowing it to penetrate into the test block. 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 penetrate the block beyond 5.0 ± 0.5 mm measured from the bottom of the mold.
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 to a point 5.0 ± 0.5 mm measured from the bottom of the mold shall be the initial setting time.From IS Code 4031 part 5
Relevant is code: IS code 4031 part 5 Initial Setting time of Cement.
Normally Initial setting time :
O.P.C (Ordinary Portland Cement) 30 min.Initial Setting time of Cement
Rapid Cement 5 min Initial Setting time of Cement
Also Read :LAB TEST ON AGGREGATES AT SITE
What Is Final Setting time of Cement?
Any cement paste stating time of Cement paste is loose cement past to going hard shape of cement pest. All complete prosses of Cement Harding final time call final setting time of cement.
Determination of Final Setting Time: from IS Code 4031 part 5, page no 2, cl 5.3
Replace the needle ( C ) of the Vicat apparatus by the needle with an annular attachment ( F ). The cement shall be considered as finally set whenFrom IS Code 4031 part 5
Upon applying the needle gently to the surface of the text test block, the needle makes an impression thereon, while the attachment fails to do so.From IS Code 4031 part 5
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.
In the event of a scum forming on the surface of the test block, use the underside of the block for the determination
Relevant is code: IS code 4031 part 5 Final Setting time of Cement.
Also Read : PROCEDURE FOR RCC CONCRETE
CONSISTENCY TEST OF CEMENT
To determine the standard consistency of test of Cement
This procedure covers all relative activity for the project site.
a) Vicat’s apparatus
Vicat apparatus conforming from IS: 5513-1976
d) Measuring cylinder
e) Non-porous plate
Also read: SOUNDNESS OF CEMENT TEST
a) Take about 500 gms cement and prepare a paste with a weight quantity of water (say 24 percent by weight of cement) for the first trial.
b) The paste must be made in a conventional manner and filled into the Vicat mold within 3-5 minutes.
c) After complete filling, the mold shakes the mold to expel air.
d) A standard plunger 10mm diameter, 50mm long is attached and brought down to touch the surface of the paste in the test block & quickly released, allowing it to sink into the paste by its own weight.
e) Take the reading this reading note down the depth of penetration of the plunger.
f) Conduct a 2nd trial (say with 25 percent of water) and find out the depth of penetration of plunger. Similarly,
g) Conduct trials with higher water/cement ratio till such time of plunger penetrates a depth of 33-35 mm from the top.
h) That particular percentage of water maximum allows the plunger to percentage only to a depth 33-35mm from the top is known as the %(percentage) of the water required to produce the cement paste of standard consistency.
i) The test is expected required to be conducted at a constant temperature (27°± 2°) C & constant humidity (90%)
Express the amount of water as a % by weight of the dry cement
Also read : IS CODE FOR CIVIL ENGINEER [Q&A]
Express the amount of water as a percentage by mass of the dry cement to the first place of decimal.