The asphalt overlay on the old asphalt concrete pavement is different, and the asphalt overlay will bear with the old asphalt concrete pavement. Therefore, the asphalt overlay on asphalt concrete pavement will not only cause reflection cracks, but also cause fatigue cracks due to long-term load.
Asphalt concrete pavement refers to the pavement with asphalt concrete as the surface layer. A mixture made by manually selecting mineral aggregates (crushed stone or gravel, stone chips or sand, mineral powder, etc.). ) mixed with a certain proportion of road asphalt materials under strictly controlled conditions.
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In the preparation process, most of the sand and gravel in the past were dried and heated before being mixed with hot asphalt and cold mineral powder. Recently, a method of mixing wet aggregate with hot asphalt first, then heating and fully mixing is developed to eliminate fly ash when aggregate is heated and dried.
When the latter process is adopted, it is best to use asphalt anti-stripping agent at the same time to prevent the residual moisture in the mixture from affecting the service life of asphalt concrete, so as to enhance water resistance.
Different countries have different specifications for asphalt concrete. The Technical Specification for Hot-mixed Hot-paved Asphalt Mixture formulated in China is called asphalt concrete with void ratio below 10%, which is subdivided into type I and type II. Type I porosity is 3 (or 2) ~ 6%, which belongs to dense grading type.
Type ⅱ is 6 ~ 10%, which belongs to semi-open classification type; The void ratio above 10% is called asphalt macadam, which belongs to open grading type; The physical and mechanical indexes of the mixture include stability, flow value and porosity.
Baidu encyclopedia-asphalt concrete pavement
Baidu encyclopedia-asphalt pavement