Why asphalt pavement cracks?

(1) construction of cold joints are not well treated, the joints are not tight, poor combination.

(2) asphalt low-temperature deformation resistance is poor, resulting in asphalt pavement contraction cracking at low temperatures.

(3) asphalt pavement layer thickness is insufficient, under the action of traffic loads produce structural cracks.

(4) Semi-rigid grass-roots contraction cracks produced by reflection cracks.

(5) bridge, culvert on both sides of the roadbed fill settlement, resulting in cracking.

Extension of the answer:

Bitumen is a complex mixture of different molecular weights of hydrocarbons and their non-metallic derivatives composed of black-brown, is a kind of high-viscosity organic liquids, liquid, with a black surface, soluble in carbon disulfide. Bitumen is a kind of waterproof and moistureproof and anti-corrosion organic cementitious material. Bitumen can be mainly divided into three kinds of coal-coke asphalt, petroleum asphalt and natural asphalt: among them, coal-coke asphalt is a by-product of coking.

Interpretation of colloidal structure, with the reduction of saturated and aromatic content of the dispersing medium, the protective material gel and the dispersed phase asphaltene content increases, the asphalt from the sol-gel structure into a sol-gel structure to the gel structure. The degree of penetration in the technical index of asphalt decreases and the softening point increases. And when the asphalt in the proportion of the content of each component is coordinated, can get the best ductility.

In civil engineering, asphalt is widely used in waterproofing materials and anticorrosion materials, mainly used in roofing, ground, underground structure of waterproofing, wood, steel corrosion. Asphalt is also widely used in road engineering pavement structure binder material, which can be built into different structures of asphalt pavement with different compositions of mineral materials according to the proportion of the highway is more widely used.