Prime coat: Prime coat oil must be sprayed within 6 hours after the base course is rolled. The prime coat oil is emulsified asphalt PC-2, and the dosage can be determined by trial spraying per square meter 1.5 liter, and the penetration depth is not less than 5 mm After the prime coat oil is sprayed, the emulsified asphalt PC- 1 lower seal coat is spread, and the dosage of emulsified asphalt is per square meter 1.0l, and the aggregate particle size is 0.5 ~/kloc-0. The adhesive layer oil is emulsified asphalt PC-3, and the dosage is 0.5 liter per square meter. 1. In rainy and humid areas, the porosity of asphalt surface layer of expressway and Class I highway is large, which may cause serious water seepage, or the asphalt surface layer cannot be paved in time at the paving base. When vehicles need to pass, it is advisable to spray permeable oil layer before paving the seal coat. The difference between the lower seal coat and the prime coat oil must be strictly distinguished: the purpose of the lower seal coat is to seal the surface, which does not necessarily require infiltration; Permeable oil needs to penetrate to a certain depth. At the same time, its function and purpose are quite different. At present, in some projects, aggregate and sand are sprinkled on the priming oil as the lower sealing layer because it can't penetrate the semi-rigid base, so it may play a sealing role, but it can't replace the priming oil. 4. Slurry seal coat is generally used for the preventive maintenance of secondary and below roads, and is also suitable for the lower seal coat of new roads. 4.2.9 The lower seal coat is a structural layer set on the surface of semi-rigid base, with the purpose of protecting the base from being damaged by construction vehicles, which is beneficial to the health of semi-rigid materials, preventing rainwater from infiltrating into the structural layer below the base, and strengthening the combination of surface layer and base. Although there are many methods to make the lower seal coat, practice has proved that asphalt single-layer pavement is one of the economical and effective methods. Function and application conditions of permeable layer, adhesive layer and sealing layer. (1) The function and applicable conditions of the prime coat are as follows: the asphalt surface layer is well combined with the non-asphalt base layer, and emulsified asphalt, coal asphalt or liquid asphalt is poured on the base layer to form a thin layer on the surface of the base layer. When the following conditions are met, prime asphalt shall be poured: ① Graded macadam and graded macadam base of asphalt pavement. ② Cement, lime, fly ash and other inorganic binders stabilize the soil. (3) Granular semi-rigid base must be sprayed with prime asphalt. (2) Function and applicable conditions of the bonding layer: The function of the bonding layer is to spread a thin layer of asphalt material to strengthen the bonding between asphalt layers of pavement and between asphalt layers and cement concrete pavement. Under the following circumstances, viscous asphalt should be poured: ① Before paving the upper layer, the asphalt layer under the double-layer or three-layer hot-mix hot-mix asphalt pavement has been polluted. (2) Laying an asphalt layer on the old asphalt pavement layer. (3) Paving asphalt pavement on cement concrete pavement. ④ Sides of kerbs, rainwater inlets, inspection wells, etc. Contact with the newly laid asphalt mixture. (3) The function and applicable conditions of seal coat The function of seal coat is to close the surface gap and prevent moisture from soaking into the thin layer of asphalt mixture laid on the surface or base. What is spread on the surface of the surface layer is called the upper seal layer, and what is spread under the surface layer is called the lower seal layer. When one of the following conditions is met, the seal coat should be laid on the asphalt surface: ① The asphalt surface has a large gap and serious water seepage. ② Cracked or repaired old asphalt pavement. (3) Old asphalt pavement that needs to be paved with wear layer to improve the anti-skid performance. (4) New asphalt pavement that needs to be paved with wear layer or protective layer. (4) Function and applicable conditions of slurry seal coat: The function of slurry seal coat is to mix properly graded stone chips or sand and fillers (cement, lime, fly ash, stone powder, etc.) into asphalt seal coat. ), emulsified asphalt, additives and water are mixed in a certain proportion and evenly spread on the road surface. Under any of the following circumstances, the lower seal coat should be laid below the asphalt surface layer: ① It is located in a rainy area, with a large gap in the asphalt surface layer and serious water seepage. (2) After the base course is paved, the asphalt surface can't be paved in time, so the traffic must be opened. 1. The function of the prime coat: By spraying emulsified asphalt, coal asphalt or liquid asphalt on the base, the asphalt surface layer is well combined with the non-asphalt base and penetrates into the thin layer on the surface of the base. 2. Under the following circumstances, prime asphalt shall be poured: (1) graded macadam of asphalt pavement and graded macadam base; (2) inorganic binders such as cement, lime and fly ash stabilize the soil; (3) Granular semi-rigid base must be sprayed with prime asphalt. 1. The function of the bonding layer: make the upper and lower asphalt structural layers or asphalt structural layers and the structure (or cement concrete pavement) completely bonded into a whole. 2. Viscous asphalt should be sprayed in the following cases: (1) Before paving the upper layer, the asphalt layer under the double-layer or three-layer hot-mix asphalt pavement has been polluted. (2) Overlay an asphalt layer on the old asphalt pavement layer. Or before the deck is paved. (3) paving an asphalt surface layer on the cement concrete pavement; (4) Sides of kerbs, rainwater inlets, inspection wells, etc. Contact with the newly laid asphalt mixture. 1. The function of sealing layer: First, it seals a certain layer to play the role of water retention and waterproof; The second is the transition and effective connection between the base and the asphalt surface; The third is the reinforcement of the loose part of a certain pavement; Fourth, before paving the asphalt pavement at the grass-roots level, traffic should be temporarily opened to prevent the grass-roots level from being damaged by water due to weather or vehicles. Seal coat can be divided into upper seal coat and lower seal coat; According to the construction type, single-layer surface treatment can be carried out by mixing method or layering method, and emulsified asphalt slurry seal can also be used. 2. Under any of the following circumstances, the asphalt surface layer of the upper seal coat (1) should be paved with large gaps and serious water seepage. (2) Cracked or repaired old asphalt pavement. (3) Old asphalt pavement that needs to be paved with wear layer to improve the anti-skid performance. (4) New asphalt pavement with wearing layer or protective layer.