What is the primary reason joints in HMA fail prematurely?

The primary reason joints in Hot Mix Asphalt (HMA) fail prematurely is due to not enough material at the joint. When there is insufficient material at the joint, it creates a weak point that can lead to separation and cracking. The integrity of the joint relies heavily on having enough asphalt material to provide adequate bonding and support between joints. A well-compacted joint with sufficient material ensures that it can withstand the stresses from traffic and environmental factors.

Inadequate material may not allow for proper compaction to occur, which can further exacerbate the issue, leading to moisture infiltration and resistance to shear forces. Hence, ensuring that there is enough material at the joint is vital for maintaining the durability and longevity of the pavement. This highlights the importance of meticulous planning and execution during the paving process to ensure adequate material is used at all joints.