I. Introduction of Products
SBR modified asphalt bridge deck waterproof coating is a water-based waterproof coating prepared by using styrene-butadiene rubber as the main material, compounding with various rubbers to modify asphalt and using water as the medium.The product is non - toxic, tasteless, free of environmental pollution and cold for construction.The most important advantage is that the rubber in the modified asphalt forms a continuous network that runs through each other and cross - links, making the modification exhibit high polymer properties.After the coating film is dried, the rubber elasticity is maintained and the film is flexible at low temperature.It has strong shear resistance, can withstand long-term load on the bridge deck and resist pressure, can prevent water seepage from causing structural damage, and can delay the service life of highway bridges.It is the most ideal waterproof material for bridge deck, and can also be used for waterproofing, seepage prevention, corrosion prevention, wall waterproofing and moistureproofing in roofing, underground, tunnel, tunnel and other projects.SBR modified asphalt bridge deck waterproof coating not only has good waterproof performance, but also can absorb stress and noise of road and bridge surface as a stress absorbing layer.Due to its elastic and plastic deformation ability, it can bear loads without being damaged.Alleviate road and bridge surface aging and delay service life.
II. Preparation before Construction
(1) before the waterproof adhesive layer construction
1. The cement concrete bridge deck shall be smooth, dry, clean, free of laitance, oil stain and steel bars
The treatment method is as follows:
1, convex, available grinding machine grinding or leveling with chisel hammer, etc.;Cutting the steel bar protrusion to the root, and treating the end with epoxy resin after derusting;
2, sag, for cracks, should be first cut into V shape, after removing debris with the same label cement mortar filling;Cut a shallow trench to the lower lateral side where the depression area is large and gentle to facilitate drainage.
3, laitance loose, peeling and other available cleaning planer, etc.
4. Oil can be decomposed and removed with soda water or burned with oxygen finch flame gun. If it is not complete, it should be cut off until there is no oil mark.The flatness of the control bridge panel is less than 5 mm, but it should be smooth and rough rather than smooth so as to form enough friction between the waterproof adhesive layer and the cement concrete to resist the interlayer shear force caused by the braking of heavy-duty vehicles.The false joint of bridgehead slab shall be padded with rubber asphalt sealant in strict accordance with the requirements of drawings.Finally, before the construction of the waterproof bonding layer, the dust, stone chips, sand grains and other residues on the bridge deck and the decking board shall be thoroughly removed and cleaned with a steel brush and a high-pressure water gun, and the waterproof bonding layer shall be constructed after the bridge deck is free of water and dry.
(2) preparation for construction
1. The SBR waterproof adhesive layer adopts a self-propelled asphalt distributor, which mainly consists of a thermal insulation asphalt tank, a heating system, a transmission system, a circulating spraying system, a control mechanism, inspection and measuring instruments, etc.The control of the distribution quantity is realized by controlling the working parameters of the distributor such as the width of the distributor nozzle, the height of the nozzle, the speed of the vehicle and the quantity of the pump, etc. Before the formal construction, a trial distribution must be carried out to determine the relationship between the distribution quantity and the working parameters of the asphalt distributor.
2. Carry out necessary inspection and maintenance on the distributor, such as checking whether the oil quantity is enough, whether the instrument is normal, whether there is leakage in pipelines and joints, whether all kinds of operating devices are flexible, etc.
3. Before loading the paint, clean the distributor: thoroughly clean the asphalt in the tank, clean the chassis of the car, remove dirt and debris, and remove the asphalt binder from all pipelines.
4. Add a filter screen with a diameter of 3 mm to 5 mm to the asphalt pump entrance or asphalt truck to prevent debris in the asphalt pool from entering the distribution truck to prevent clogging of the nozzle and resulting in uneven distribution on the bridge deck.
(3 ) spraying requirements
1, SBR waterproof coating heating should be carried out in the mixing station, heating to 185 ℃, the distributor heating system to heat and insulate the asphalt to ensure that the asphalt distribution is above 180 ℃.
2. When spraying asphalt, the asphalt distributor should maintain a stable speed and amount of spraying, and keep the entire width of spraying uniform. Pay attention to the nozzle of the distribution equipment should be suitable for the consistency of asphalt, ensuring it can be atomized and form an included angle of 15 ~ 25 with the oil spraying pipe. The height of the oil spraying pipe should be such that the asphalt sprayed by 2 ~ 3 nozzles can be accepted at the same place, and there should be no white leakage, and the parts not sprinkled on the opposite side should be manually patched to the thickness of the modified asphalt.
3. Use kraft paper or striped cloth or felt on both ends of the bridge deck to pave the boundary between the starting point and the ending point neatly so that the asphalt sprayed from the abnormal state during the start and stop of the asphalt distributor will fall on the kraft paper paved in advance and keep the whole site clean.
4, SBR waterproof adhesive layer thickness requirements, the distributor should consider the asphalt density and distribution loss when setting the distribution quality.
5. The distribution quality is mainly measured by the distribution quantity and distribution uniformity, which is mainly determined by observation, and the distribution quantity is determined by converting the material density into the distribution thickness.Spraying SBR waterproof adhesive layer twice: wait for the first layer of coating to dry before spraying for the second time.
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