Write notes on Mixing and Mixer machines of concrete.
Thorough mixing of the materials is essential for the production of uniform concrete. The mixing should ensure that the mass becomes homogeneous, uniform in color and consistency. There are two methods adopted for mixing concrete:
As per IS: 1791-1985, concrete mixers are designated by a number representing its nominal mixed batch capacity in lit. The following are the standardized sizes of three types:
What are the initial and final setting times of cement ? How are they experimentally determined ?
Explain Kelly Ball to measure the workability of concrete. Mention the limitation of the test.
How standard consistency test is done on cement? Explain the procedure briefly.
Give the physical characteristics of 53 grade OPC.
What are flaky and elongated aggregates? How can the shape of aggregate influence strength of concrete? Following is the result of a sieve analysis of 500 gm aggregate:
|IS sieve size
|lower than 150 micron
|Weight retained in gm
Find out the 'Fineness Modulus' of the sample