What is the required temperature at the time of spreading and compaction of conventional hot mix asphalt?

The required temperature at the time of spreading and compaction of conventional hot mix asphalt is at least 139°C. Achieving this temperature ensures that the asphalt remains workable and pliable, which is critical for proper placement and compaction. At temperatures below this threshold, the asphalt may not achieve the necessary flow characteristics, leading to difficulties in the mixing and spreading processes, which could compromise the integrity and durability of the pavement.

Maintaining the appropriate temperature also helps in achieving proper bonding between the asphalt and the aggregate, ensuring a well-compacted and durable surface. This helps to prevent issues like raveling or segregation. During the compaction phase, the asphalt must be in a sufficiently viscous state to allow for effective density to be achieved without causing damage to the aggregate structure. Thus, specifying a minimum temperature of 139°C is aligned with the best practices in asphalt technology for optimal performance of the finished pavement.