When might cracking and seating be executed in asphalt operations?

Cracking and seating is a method employed in asphalt operations specifically aimed at mitigating reflective cracking in overlay applications. Reflection cracking commonly occurs when cracks from an underlying layer propagate through a new overlay, which can compromise the integrity and performance of the pavement. By executing cracking and seating, the existing pavement is intentionally cracked into smaller pieces, which allows the overlay to better adhere to the surface and absorb stresses, thereby reducing the likelihood of cracks reflecting upward.

This technique is particularly beneficial as it transforms the old pavement into a more flexible base layer and helps to distribute stresses over a larger area, minimizing the potential for future cracking. It is not utilized for creating a new subgrade, necessary only during extensive resurfacing, or, as suggested in one of the other options, in conditions of extreme heat, which could lead to complications and inappropriate application of the technique.