Various diseases of asphalt pavement are related to groundwater and surface water in varying degrees. Waterproofing is an important measure, even a fundamental measure, to improve the durability of asphalt concrete. One of the main causes of water damage to asphalt pavements is that the air voids of asphalt mixtures are too large. According to relevant information, the air void ratio is between 8% and 12%, and road water is likely to invade the surface layer mixture. Once the asphalt surface layer contains a certain amount of moisture, the water will flow freely inside the asphalt mixture, plus vehicle load Due to the repeated action of the surface layer, the water in the surface layer produces a pressure force. This part of the water gradually penetrates into the interface between the asphalt and the aggregate, causing the asphalt film to gradually separate from the surface of the aggregate, ultimately resulting in the adhesion between the asphalt and the aggregate. Loss, causing water damage and destruction. Therefore, the requirement of asphalt mixture for waterproofing raw materials is also the key to reducing damage to asphalt pavement.
Asphalt materials Asphalt materials used in asphalt pavements include petroleum pitch, coal pitch, liquid petroleum pitch, and asphalt emulsion. The number of asphalt materials used in various asphalt pavements should be determined according to factors such as the type of pavement, construction conditions, regional climate conditions, construction season, and the nature and size of mineral materials. However, when the bituminous material is heated (generally heated to 170℃～180℃ during production), the water in the pores will change from liquid to gas. Due to volume expansion, most of the water vapor will be discharged from the pores. Because the surface tension of the hot asphalt is very small, and The dry aggregate has very good wettability, so the hot asphalt will easily enter the pores of the aggregate, which will evaporate harmful water and reduce the harm to the asphalt pavement.
