When is it necessary to consider reflective cracking in HMA?

Reflective cracking is a significant concern in Hot Mix Asphalt (HMA) applications, particularly in the context of underlying concrete pavements, such as Portland Cement Concrete (PCC) slabs. The process of rubblizing involves breaking the existing concrete into smaller pieces to create a stable base for new asphalt layers. During this process, it’s essential to consider reflective cracking because the underlying joints and cracks of the PCC can propagate through the overlying asphalt layer if not properly addressed.

When rubblizing, if the new asphalt is placed without adequate attention to the potential for reflective cracking, the stresses can cause reflection of the underlying cracks to the surface of the new pavement. Therefore, strategies to mitigate reflective cracking, such as using appropriate interlayers or specific asphalt mixes, become crucial at this stage.

Considering reflective cracking at this point allows for proactive measures that can enhance the durability and longevity of the new HMA surface, ultimately leading to better performance and reduced maintenance costs in the future. Addressing reflective cracking during the rubblization process helps ensure a more effective bond and distribution of stress across the pavement system.