Let the characteristic strength be defined as that value, below which not more than 50% of the results are expected to fall. Assuming a standard deviation of 4 MPa, the target mean strength (in MPa) to be considered in the mix design of a M25 concrete would be

Consider the following statements for air-entrained concrete:

(i) Air-entrainment reduces the water demand for a given level of workability

(ii) Use of air-entrained concrete is required in environments where cyclic freezing and thawing is expected.

Which of the following is TRUE?

Workability of concrete can be measured using slump, compaction factor and Vee bee time. Consider the following statements for workability of concrete:

(i) As the slump increases, the Vebe time increases

(ii) As the slum increases, the compaction factor increases

Which of the following is TRUE?

The flexural tensile strength of M25 grade of concrete, in N/mm², as per IS:456-2000 is __________.