Question { L&T, 27182 }

What is the diffence between prescribed mix and design mix

Answer

Designed mix for which plant/producer is responsible for
selecting the mix proportions to produce required strength
or performance whilst the prescribed mixes for which the
proportions have to be in accordance with the quantities
specified in BS or specification. The producer/plant is
responsible for ensuring that these proportions will produce
a concrete with the performance/strength he requires.

Question { Raj Construction, 11722 }

what is the requierd compressive strenth for m 20 grade concreat for
7 days?

Answer

75% of 20kn/m2 is required, i.e= 15kn/m2