Type:
1, ordinary cement concrete (or asphalt concrete) pavement: In small-span bridges in non-cold areas, it is usually unnecessary to make a special waterproof layer on the bridge deck, but a 5-8 cm ordinary cement concrete or asphalt concrete pavement layer is directly laid on the bridge deck. Generally, the strength grade of pavement concrete is the same as or slightly higher than that of bridge deck concrete, which requires good compactness when paving. The General Code for Design of Highway Bridges and Culverts (JTG D60-2004) stipulates that the thickness of cement concrete bridge deck pavement (excluding leveling layer and cushion layer) is not less than 80mm, and the concrete strength grade is not less than C40. In order to prevent slip and reduce light reflection, it is best to make concrete into a rough surface.
Concrete pavement has low cost and good wear resistance, which is suitable for heavy traffic, but the maintenance period is longer than that of asphalt pavement, so it is more troublesome to maintain it in the future. The super-large bridges and bridges on expressways and first-class highways should be paved with asphalt concrete deck, the thickness of which should not be less than 70 mm The asphalt concrete pavement is light in weight and convenient to maintain, and it can be put into use in just a few hours after paving. The asphalt concrete pavement on the bridge can be made into single layer (7 ~ 10 cm) or double layer (bottom layer 4 ~ 5 cm, surface layer 3 ~ 4~5cm).
2. Waterproof concrete pavement: When bridges in non-freezing areas need proper waterproofing, 8 ~ 10 cm thick waterproof concrete can be paved on the bridge deck. The strength grade of waterproof concrete is generally not lower than that of bridge deck concrete, and there is generally no additional surface layer on it. However, in order to prolong the service life of the bridge deck, 2cm thick asphalt surface treatment agent should be laid on it as a repairable wear layer.
3. Cement concrete or asphalt concrete pavement with adhesive or paint waterproof layer: Flexible adhesive or paint waterproof layer is often used on bridges with high waterproof requirements, or on bridges where cracks may occur when the bridge deck is located in the tensile area of the structure. The adhesive waterproof layer is arranged on the low-strength concrete triangular cushion. The method is as follows: firstly, smooth the cushion layer with cement mortar; After hardening, coat a layer of hot asphalt primer; Then, cover it with a layer of linoleum (or sack cloth, glass fiber cloth, etc.). ); Then coat with a layer of asphalt cement; Finally, apply a layer of asphalt cement.
Usually the so-called "three oils and two felts" waterproof layer has a thickness of about 1 ~ 2 cm. In order to protect the adhesive waterproof layer from being damaged by pavement laying and renovation, fine aggregate concrete with a thickness of about 4cm and low strength should be used as the protective layer. When sufficient strength is reached, asphalt concrete or cement concrete pavement will be laid.
Extended data:
Bridge deck pavement requirements:
1, lightweight. Generally, the increase of bridge deck pavement thickness will not enhance the overall stiffness of the bridge structure, but increase the dead load of the bridge, especially for long-span bridges, the weight of bridge deck pavement may have a greater impact on the economy of the bridge. Therefore, the bridge deck pavement is required to be as thin as possible to reduce the weight.
2. Flexibility (scalability). The bridge will flex under the action of vehicle load, which makes the deck pavement flex and deform. Therefore, under repeated loads, bridge deck pavement is prone to fatigue cracking. Good flexibility of paving materials can weaken or avoid bending and cracking of paving layers.
3. Deformation stability. The elastic modulus of bridge deck pavement materials is generally much smaller than that of bridge deck, and the pavement layer is thin (generally 5 ~ 8 cm). Under the action of vehicle load, bridge deck pavement is in a more unfavorable stress state than ordinary pavement. Especially in high temperature season, asphalt bridge deck pavement is prone to plastic deformation and slip, forming waves and ruts. Therefore, pavement materials are required to have good deformation stability and good adhesion with the bridge deck to avoid plastic deformation and slip.
4. Watertightness. The leakage of bridge deck pavement will lead to the corrosion of steel bars in steel bridge deck or concrete. Therefore, compared with ordinary pavement, the anti-seepage requirements of bridge deck pavement are higher.
5. smoothness. Smooth bridge deck pavement can not only meet the requirements of smooth and comfortable driving of vehicles, but also reduce the impact of vehicle load on bridge structure, improve the stress condition of the bridge, and be beneficial to the drainage of pavement surface.
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