Reflective Cracking occurs generally over PCC concrete pavements due to movement in what?

• A. Oscillations in surface weather
• B. Movement in underlying layers
• C. Traffic-induced shear
• D. Surface drying cracks

Answer: (B)

Reflective cracking happens when movement along the joints and cracks in the underlying PCC pavement is transmitted up into the asphalt overlay. The concrete slab expands, contracts, and shifts with temperature and loading, and because the overlay is bonded to that moving surface, cracks form in the asphalt following the same lines as the concrete joints. So the key factor is movement in the underlying layers. Surface weather changes, traffic-induced shear, or surface drying cracks describe other issues and don’t capture why the cracks appear aligned with the concrete joints.