Volume-IF - JantERmantER

DCPL-K4A02
as per Table-2 of IS:456. All other relevant clauses of IS:456 shall also
apply.
3.6 Minimum Cement Content
The minimum cement content for each grade of concrete shall be as per
Table-5 of IS : 456.
3.7 Water-Cement Ratio
The choice of water-cement ratio in designing a concrete mix will depend on -
a) The requirement of strength.
b) The requirement of durability.
3.7.1 Strength Requirement
In case of 'Design Mix Concrete', the water-cement ratio of such value as to
give acceptable test results as per IS:456, will be selected by trial and error.
The values of water-cement ratios for different grade and mix designs will
have to be established after conducting sufficiently large number of
preliminary tests in the laboratory to the satisfaction of the Engineer.
Frequent checks on test will have to be carried out and the water-cement
ratios will be revised if the tests produce unsatisfactory results.
Notwithstanding anything stated above the Contractor's responsibility to
produce satisfactory test results and to bear all the consequences in
case of default remains unaltered.
In case of nominal mix concrete, proportions for different grades of
concrete is specified in Table-9 of IS:456 and no tests are necessary. The
acceptance test criteria for nominal mix concrete shall be as per IS:456.
3.7.2 Durability Requirement
Table-5 of IS:456 gives the maximum water-cement ratio permissible
from the point of view of durability of concrete subjected to adverse exposure
to weather, sulphate attacks, and contact with harmful chemicals.
Impermeability may also be an important consideration.
(PCA.774.S034sca2) V.II-D2/S-III : 15