Treatment before paving.
When the paving speed remains unchanged, if the gate opening height is too large, resulting in excessive mixture accumulation in the spiral paving chamber, it will cause overload of the spiral paver and accelerate the wear of its blades.
When the temperature of the screed is low, the hot asphalt mixture will adhere to the bottom of the slab when it contacts the bottom surface of the unheated screed.
Sharp protrusions or pits shall be polished or repaired.
Survey and set out the elevation of cross slope control points.
The bridge deck shall be flat, rough, dry and tidy without dust, debris or oil stain.
The asphalt mixture shall be received at the paving place with the material transportation list.
The mixture transported by the truck shall be covered with tarpaulin for thermal insulation, rainproof and pollution prevention.
Spraying adhesive layer is a thin layer of asphalt poured to make the newly paved asphalt surface layer bond well with the lower surface.
Pouring adhesive layer (1) before paving asphalt concrete, adhesive layer asphalt shall be sprayed.
When the paver moves forward, the asphalt mixture attached to the base plate will crack the surface of the paving layer, form grooves and cracks, and affect the paving quality, The temperature of the screed shall not be lower than 80 ℃.
During the transportation of hot mixture for paving asphalt surface course (1), it shall be insulated, protected from sun and pollution, and the temperature transported to the site shall meet the design requirements.
If the mixture does not meet the construction temperature requirements, or has formed agglomerates and been exposed to rain, it shall not be paved.
(2) When paving asphalt concrete on the bridge deck, the elevation and flatness shall be controlled by the method of double steel wire benchmark.
The paver transports the mixture back to the dividing room while receiving the material, and then starts paving the mixture at a predetermined speed..
The opening height of the gate shall ensure that the height of the mixture pile in the paving room is flush with or slightly higher than the axis line of the spiral paver, so as to just see the spiral blade or just cover the spiral blade.
Paving waterproof layer (1) the bridge deck waterproof layer shall be painted with polymer asphalt (special for bridge deck) waterproof coating.
3.
(3) After spraying emulsified asphalt for tack coat, the asphalt layer shall be paved immediately after demulsification and water evaporation, so as to ensure that the tack coat is not polluted.
The temperature during paving shall not be lower than 10 ° C.
② The feeding mechanism operates the feeding mechanism of the paver, including a scraper conveyor and a spiral distributor for cloth on both sides.
(4) Paving method: hot mix asphalt mixture is mainly paved mechanically.
If the gate is opened too small, there will be less mixture in the paving chamber and the middle part will be sunken, which will reduce the resistance to the screed and destroy the stress balance of the screed, resulting in the sinking of the screed and the reduction of paving thickness.
High temperature will not only deform the screed itself and accelerate wear, but also aging the asphalt on the surface of the paving layer and trenching, affecting the flatness and strength of the structural layer.
1、 Construction process 1.
If it does not meet the requirements, it shall be treated.
(2) The tack coat oil shall be sprayed by a motorized asphalt spreader with a spraying amount of 0.5l/m2.
The truck must be cleaned before and after each use, and a thin layer of isolating agent or anti adhesion agent to prevent asphalt bonding shall be coated on the carriage plate, but no residual liquid shall accumulate at the bottom of the carriage.
Before asphalt concrete paving, the cement concrete bridge deck shall be inspected.
Report to the supervising engineer for inspection, and pave if it is qualified.
(2) The waterproof layer of the bridge deck must be fully paved on the whole bridge deck, and the coating must be mixed evenly; The protective layer shall be paved immediately after the waterproof layer is paved.
The floating debris and dust shall be removed manually, and then the bridge deck shall be cleaned with high-pressure water gun to facilitate the good combination of asphalt concrete pavement and bridge deck.
The preheating temperature of the screed shall be close to the temperature of the asphalt mixture.
The running speed of the scraper conveyor and the opening height of the gate jointly affect the material supply to the paving chamber.
Before construction, the expansion joint shall be filled with mortar or asphalt mixture to prevent the paver from being disturbed during paving, so as to ensure the thickness and flatness of bridge deck pavement.
(3) When the truck enters the paving site, the tires shall not be stained with dirt that may pollute the road.
When rolling the asphalt surface of the bridge deck, light roller shall be used for rolling, and large vibratory roller or heavy roller that may damage the bridge shall not be used for rolling.
In order to prevent dirt and other pollutants on the tires, a water truck filled with water shall be parked 100m away from the front yard to clean the possible pollutants, and two fast air dryers shall be set to dry the truck tires, Ensure that the tire surface is clean and dry when the truck enters the paving site.
Generally, the operation speed of the scraper conveyor is determined and generally does not move frequently, and the feeding amount is mainly controlled by the opening height of the gate.
4.
Attention shall be paid to uniform distribution without excessive or missing spraying.
When the temperature of the screed is too high, the quality of the paving layer will also be affected.
The purpose of heating the screed is to reduce the temperature difference between the screed and its accessories and the asphalt mixture.
After spraying the adhesive layer oil, other vehicles and pedestrians outside the material truck are strictly prohibited to pass through.
During paving, the temperature of asphalt mixture shall be detected, The temperature control is shown in the table below: the temperature of asphalt mixture paving and rolling construction process AC-16 transported to the site shall not be lower than 150 ℃, the temperature of mixed paving shall not be lower than 160 ℃ for normal construction, and the internal temperature of mixture rolled at 140 ℃ for low-temperature construction shall not be lower than 150 ℃ for normal construction, 135 ℃ for low-temperature construction, and the surface temperature after rolling shall not be lower than 80 ℃ for open traffic of steel wheel roller Not higher than 50 ℃ (5) paving process: ① after the heating of the screed is in place and adjusted, the preheating and thermal insulation of the paver and screed shall be done well before construction or temporary shutdown.
During construction, special personnel shall be specially assigned to take care of it.
The cross slope of the bridge deck shall meet the requirements.
③ The first dump truck slowly retreats to the front of the paver, gently contacts the receiving hopper of the paver and slowly discharges the material until the receiving hopper of the paver is full.
2.
When loading from the mixer to the truck, move the truck position for many times to balance the loading, so as to reduce the segregation of the mixture.
5.
All traffic including pedestrians is strictly prohibited before the protective layer is paved.
