What are the functions of asphalt penetration layer, sticky layer and sealing layer? Which conditions apply?
(1) The penetration layer makes the asphalt surface layer and the non-asphalt material base layer well combined, and pours emulsified asphalt, coal tar or liquid asphalt on the base layer to form a thin layer that penetrates the surface of the base layer.
When the following conditions are met, the permeable asphalt should be poured:
①Graded gravel and graded gravel base of asphalt pavement.
②Inorganic binders such as cement, lime and fly ash stabilize the soil.
③The semi-rigid base of the pellets must be poured through the asphalt.
(2) The adhesive layer is a thin layer of asphalt material sprinkled to strengthen the bond between the asphalt layer and the asphalt layer of the road surface, and between the asphalt layer and the cement concrete pavement.
Adhesive layer asphalt should be poured if the following conditions are met:
① Double-layer or three-layer hot-mix hot-paved asphalt pavement is polluted before the upper layer is laid.
②Add asphalt layer on the old asphalt pavement layer.
③ Pave asphalt surface layer on cement concrete pavement.
④The side of curbs, rainwater intakes, inspection wells, etc. that are in contact with the newly laid asphalt mixture.
(3) A thin layer of asphalt mixture paved by sealing the surface gap and preventing water from soaking into the surface layer or base layer.
The one laid on the surface of the surface layer is called the upper seal layer, and the one laid under the surface layer is called the lower seal layer.
When one of the following conditions is met, an upper seal layer should be laid on the asphalt surface:
①The voids in the asphalt surface layer are large, and the water permeability is serious.
②Old asphalt pavement with cracks or repaired.
③Old asphalt pavement that needs to be covered with a wear layer to improve the anti-skid performance.
④New asphalt pavement that needs to be paved with wear layer or protective layer.
(4) The function of the slurry seal layer: it is formed by mixing appropriately graded stone chips or sand, fillers (cement, lime, fly ash, stone powder, etc.) with emulsified asphalt, additives and water in a certain proportion. A bituminous seal layer formed by spreading the asphalt mixture evenly on the road surface.
When one of the following conditions is met, a lower seal layer should be laid under the asphalt surface layer:
①Located in a rainy area and the asphalt surface has large voids and serious water seepage.
②After laying the base, the asphalt surface layer cannot be laid in time, and traffic must be opened.
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June 9, 2022 
