This are some important test carried out on Portland cement to check quality and strength of Portland cement used in the construction. It helps to insure the usage of cement for different purpose based on it durability and strength.
The following are the important test are carried out for normal setting of Portland cement
1 Fineness test
2 consistency test
3 Soundness test
4 Tensile strength test
5 compressive test
1 Fineness Test
This test is conducted to check the proper grinding of cement. The fineness of cement is tested either by sieve method or air permeability method.
The percentage of residue left after sieving good Portland cement in 90 micron IS ( Indian Standard ) sieve should not exceed 10 %.
A good Portland cement should not have specific surface less than 2250 cm2/g of cement, id found by air permeability method.
2 Consistency Test
This test is conducted to determine the percentage of water required for preparing cement past of standard consistency.
The consistency test is perform with the help of Vicat's apparatus which determines the initial and final setting time and normal consistency of cement.
- The initial setting time of ordinary and rapid hardening cement should be less than 30 minutes.
- The finial setting time of ordinary and rapid hardening cement should not be more than 10 hours.
- the normal consistency of a Portland cement is about 25%.
3 Soundness Test
This test is carried out to detect the presence of uncombined lime and magnesia in cement which causes the expansion of cement.
The soundness of cement test is done with the help of Le Chatelier apparatus. according to Indian standard specification, the expansion should no exceed 10mm for any type of Portland cement.
4 Tensile Strength Test
This test is carried out on standard briquettes made of a good Portland cement and standard sand mortar in ( 1:3 ratio) to determine the tensile strength of cement.
The average tensile strength after 3 and 7 days of curing should not be less than 2N/mm2 and 2.5N/mm2 respectively.
5 Compressive Strength Test
This test is carried out on standard cubes made of a good Portland cement and standard sand mortar in( 1:3 ratio) to determine the compressive strength of a cement.
According to Indian standard specification, the average compressive strength for three cubes should not be less than 11.5 N/mm2 and 17.5N/mm2 after 3 and 7 days of curing respectively.
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