Civil Engineering - Concrete Technology - Discussion

Option is correct.

Because.

The extent of initial shrinkage in cement concrete and cement mortar depends on a number of factors namely :
a) Cement content "It increases with the richness of mix.
B) Water content " Greater the water quantity used in the mix, greater is the shrinkage.
C) Maximum size, grading & quality of aggregate "With the use of largest possible max.
Size of aggregate in concrete and with good grading, the requirement of water for the desired workability is reduced, with consequent less shrinkage on drying due to reduction in porosity.
Eg: For the same cement aggregate ratio, shrinkage of sand mortar is 2 to 3 times that of concrete using 20 mm maximum size aggregate and 3 to 4 times that of concrete using 40 mm maximum size aggregate.

D) Curing "if the proper curing is carried out as soon as the initial set has taken place and is continued for at least 7 to 10 days then the initial shrinkage is comparatively less.
E) Presence of excessive fines in aggregates -The presence of fines increases the specific surface area of aggregate & consequently the water requirement for the desired workability, with an increase in initial shrinkage.

i think option A should be written as a high w/c ratio. correct if I'm wrong.