As a widely used high-grade pavement material, asphalt pavement has the characteristics of high temperature stability, low temperature crack resistance, water stability and fatigue resistance.
1. Asphalt pavement has high temperature stability.
The high temperature stability of asphalt pavement is the ability of asphalt pavement to resist flow deformation. Because the strength and stiffness of asphalt pavement decrease significantly as the temperature increases. In order to better ensure that the asphalt pavement will not cause diseases such as waves, shifting, rutting, and congestion under repeated driving loads in high-temperature seasons, the asphalt pavement should have good high-temperature stability.
2. Asphalt pavement has low temperature crack resistance.
Low temperature crack resistance refers to the ability of asphalt pavement to resist low temperature shrinkage cracks. As the temperature of asphalt pavement decreases, its stiffness increases and its expansion capacity decreases.
Under the action of external loads, part of the stress on the road surface has no time to relax and gradually accumulates. When these accumulated stresses exceed the tensile strength of the material, cracking occurs, leading to pavement damage. Therefore, asphalt pavement should have lower stiffness and greater resistance to deformation at low temperatures to meet low temperature crack resistance.
3. Asphalt pavement has water stability.
Water stability refers to the ability of asphalt pavement to resist water erosion and gradually cause the asphalt film to peel off, lose grain, become loose, and become damaged due to pits.
This is because the presence of water not only reduces the cohesion of the asphalt itself, but also destroys the cohesion between the asphalt and the mineral materials in the asphalt pavement, thereby accelerating the occurrence of peeling and causing water damage to the road. Therefore, asphalt pavement must have water stability to ensure the durability of the pavement.
4. Asphalt pavement must be fatigue-resistant.
Fatigue resistance refers to the ability of asphalt pavement to resist damage under repeated loads. It is because the asphalt pavement is subjected to repeated wheel loads during use and is in a state of overlapping stress and strain changes for a long time, resulting in a gradual decline in the structural strength of the pavement.
When the load is repeated for more than a certain number of times, the stress generated in the pavement under the load will exceed the structural resistance after the strength is reduced, causing cracks in the pavement and fatigue fracture damage.