What are the preventive measures for asphalt pavement cracks?
July 29, 2022
1. Dry the base layer
The base layer should be compacted and flat, and there should be no looseness, sanding, peeling and other phenomena. The size of the moisture content of the base layer has different degrees of influence on the coating film. Generally speaking, when it is a water-emulsion type, the drying degree of the base layer can be appropriately relaxed; when it is a solvent type, the base layer must be dry.
2. Shot blasting

The roughness control standard of shot blasting is based on visual inspection without laitance. If the roughness is too large, it will bring a lot of primer and repair work, and it is also not conducive to the bond strength; if the roughness is too small, it will lead to stickiness. The knot is not enough. When leveling the local concrete at the root of the protective wall of the bridge deck, an angle grinder can be used to avoid obvious uneven groove marks, so that the edges are straight and flat to ensure the effective bonding between the concrete paving layer and the asphalt surface layer.


3. Waterproof layer painting
The base layer of highway bridges is coated with waterproof coating. It should be applied evenly, with uniform thickness and layered waterproof coating. Usually it can be done 2-3 times. When spraying the second and third layers of waterproof paint, it is necessary to wait for the previous layer to dry before spraying, and the interval should not be less than 24h. The direction of each coating application should be perpendicular to the previous one.
4. Waterproof layer maintenance
After the waterproof layer is laid, it is strictly forbidden for vehicles to drive on it and people to step on it before laying asphalt concrete on the bridge deck, and the waterproof layer is protected to prevent moisture and pollution.
The waterproof layer of the coating shall not carry out other construction operations or directly stack items on the waterproof layer without taking protective measures.
With the development of social economy, the number of private cars is rising sharply. The increase in traffic will increase the burden on the bridge deck, so it is very important to ensure the quality of the bridge deck. During construction, a reasonable design scheme should be selected to ensure the quality of highway bridge construction and avoid the appearance of bridge deck cracks.