What does "thermal segregation" refer to in asphalt placement?

Thermal segregation refers to the variation in temperature within a load of asphalt mix. This phenomenon can occur due to several factors, such as improper mixing, variations in the delivery method, or delays during transportation and placement. When thermal segregation happens, it leads to inconsistencies in the material properties of the asphalt, ultimately affecting the performance and longevity of the pavement.

Properly maintained temperature is crucial for achieving the intended compaction and ultimately the desired strength and durability of the asphalt layer. If there are significant temperature differences within the load, certain areas may not compact as well as others, leading to potential weak spots in the pavement structure. This makes understanding and addressing thermal segregation a key aspect for ensuring the quality of asphalt placement.