What is the best practice for rolling joints in HMA?

Rolling joints in Hot Mix Asphalt (HMA) is crucial for ensuring a seamless, well-compacted surface. The best practice is to roll the joint with a majority of the drum on the hot side. This method allows for optimal compaction of the joint area because the HMA is still in a pliable state, promoting better bonding between the two mat sections. By focusing on the hot side, the roller applies more pressure where the material is warmer and more workable, which helps achieve the necessary density and reduces the likelihood of joint deficiencies, such as raveling or cracking.

This practice contrasts with the other options; for instance, rolling with the majority of the drum on the cold side may lead to inadequate compaction since the cooler asphalt is harder and less pliable. Rolling right in the middle may not provide sufficient pressure either direction, risking poor joint integrity. Therefore, maximizing compaction strength on the hot side ensures a strong bond and durability of the asphalt joint.