The below list some common methods for testing the purity of purchased concrete.
This test is performed to know the amount of uncombined lime in supplied cement. For soundness test on cement, Le Chatelier apparatus is used. This apparatus consists of a brass mould with a diameter 30 mm, and 30 mm in height. In mould there is a split, which does not exceed 0.50 mm. Two indicators are available on each side of split. Following procedure is applied to determine soundness test on supplied cement:
To know about grinding of supplied cement, fineness test is performed. This test is done in two different ways: one is done by sieve test and another is by permeability apparatus test.
Sieve test: In sieve test, 100 gm cement is weighed and sieved through a standard sieve no. 9 for fifteen minutes. After that, residue is weighed and residue will not exceed more than 10% if it is quality cement.
Permeability apparatus test: By this test, surface area (specific surface area) of the cement particles is measured. It gives an idea about uniformity of cement particles and better than sieve analysis. Surface area of supplied cement should be more than 2250 cm2/gm.
There are four field tests for testing quality of cement as follows: