Q1: The phenomenon of reflection cracking is observed in which of the following ?

ANS:A - Bituminous overlays provided over cracked cement concrete pavements

Concepts:

The reflection Cracking occurs in bituminous overlays provided over existing cement concrete pavement. The crack pattern existing in cement concrete pavement is mostly reflected on the bituminous surfaces in the same pattern. Hence, called reflection cracking.

The presence of reflection crack on the surface the structural action is not much influenced but cracks on the surface allow surface water to seep through and cause damage to the soil sub-grade or result in mud-pumping.

Additional Data:

Shear Cracking:- Due to the inherent weakness of pavement material.
Longitudinal Cracking:- Due to frost action and Differential volume changes in the subgrade.
Alligator Cracking:- Due to relative movement or consolidation of pavement layer materials.