The 28 days cube strength of mass concrete using aggregates of maximum size 5 cm for gravity dams should be

The approx. ratio of the strength of the cement conc. of 7 days to that of 28 days is

Harshness in concrete is due to the excess of

Bulk specific gravity of an aggregate is defined as

Light weight concrete is used for

An air- entraining agent when added to cement improves

The concrete may achieve 100% strength after

The workability of concrete is defined as the