Design Mixes

Design Mixes

Cement concrete in India on large scale is being used since the last about 70 years. In the early days the following nominal ratio by volume for concrete were specified.

Cement	:	Sand	:	Aggregate
1	:	2	:	4	Correspond to M-15 Grade
1	:	1.5	:	3	Correspond to M-20 Grade
1	:	1	:	2	Correspond to M-25 Grade

IS : 456-2000 has recommended that minimum grade of concrete shall be not less than M-20 in reinforced concrete work. Design mix concrete is preferred to nominal mix. If design mix concrete cannot be used for any reason on the work for grades of M-20 or lower, nominal mixes may be used with the permission of engineer-in-charge, which however is likely to involve a higher cement content.