Q. Good surface regularity for sub-base in concrete pavement?

Surfaces of sub-base material for concrete carriageway must be built in a regular manner due to the following reasons:

(i) One of the primary functions of sub-base in concrete pavement is to provide a smooth and even interface amid concrete slab andsubgrade so that a uniform support is established. A regular surface of sub-base helps in decreasing the frictional and interlocking forces between concrete slab and sub-base and allowing shrinkage movement andeasier temperature.

(ii) A uniform sub-base surface is required in the construction of concrete slab of uniform thickness adopted in design. It saves the higher cost of concrete to make up the needed level.