The core reason for controlling temperature during asphalt pavement compaction lies in the fact that the viscoelastic properties of asphalt change drastically with temperature. Temperature directly determines the compactibility of the asphalt mixture, the final compactness, and the durability of the pavement. Improper temperature will directly lead to pavement quality defects.

1. Ensure the Compactibility of the Mixture and Achieve the Designed Compactness

Asphalt exhibits a viscous fluid state at high temperatures and a brittle solid state at low temperatures. Only within an appropriate temperature range can the mixture meet the conditions for compaction and shaping through rolling.

• When the temperature is too high: The viscosity of asphalt is too low, which easily causes the mixture to shift and bulge. Wheel tracks are difficult to eliminate during rolling, and conversely, the pavement flatness is poor.

• When the temperature is too low: The viscosity of asphalt rises sharply, making the mixture hard and less fluid. It becomes difficult for the roller to compact and interlock the particles, resulting in insufficient compactness. This will lead to problems such as voids, water seepage, and loosening in the later stage.

• Appropriate temperature range: Generally, the initial compaction temperature is controlled at 150-180°C (for ordinary asphalt), the re-compaction temperature at 130-160°C, and the final compaction temperature at 110-130°C. Within this range, the mixture can be easily compacted through rolling while maintaining structural stability.

2. Avoid Structural Defects in the Pavement

Improper temperature control will directly damage the internal structure of the asphalt pavement and leave potential quality hazards.

• Compaction at excessively high temperatures: It may cause excessive flow of asphalt particles, resulting in the "bleeding" phenomenon (excessive accumulation of asphalt on the pavement surface). This reduces the anti-skid performance of the pavement, and the insufficient interlocking force between internal aggregates can easily lead to rutting in the later stage.

• Compaction at excessively low temperatures: Particles in the mixture cannot be fully interlocked, forming a large number of tiny voids. Rainwater can easily seep into the base layer, causing softening of the base and mud pumping (the phenomenon where mud is squeezed out from under the pavement). At the same time, the overall strength of the pavement decreases, making it prone to cracks and potholes.

3. Ensure Pavement Durability and Extend Service Life

Reasonable temperature control enables the asphalt pavement to form a stable and dense structure, fundamentally improving its durability.

• Compliance with compactness requirements: Pavements rolled at an appropriate temperature can have a void ratio controlled within 3%-6% (as required by specifications). This can effectively prevent rainwater infiltration, reduce the rate of oxidation and aging, and extend the service life of the pavement.

• Structural stability: Aggregates and asphalt have a strong bond, and particles are closely interlocked. This allows the pavement to better resist the repeated action of vehicle loads, reduce the occurrence of diseases such as rutting and cracks, and lower the later maintenance costs.