The grade of concrete M₁₅₀ means that compressive strength of 15cm cube after 28 days is

According to I.S. : 456, the number of grades of concrete mixes, is

Ordinary Portland cement is manufactured from

High temperature

The quality of cement is tested by

Bulk specific gravity of an aggregate is defined as

The preliminary test is repeated if the difference of compressive strength of three test specimens, exceeds

The sound absorption coefficient of light weight concrete is nearly ......than that of ordinary concrete.