What problems should be paid attention to when paving shot blasting machine is used in bridge deck construction?

The quality of the deck surface should meet the specifications or design requirements.

(1) The surface of the road should be relatively flat, clean and dry, and the surface strength of the road should meet the specified requirements.

(2) The pellets meet the road use requirements.

(3) Sufficient workers and supporting construction tools.

Problems that should be paid attention to during the construction of road shot blasting machine

(1) The base layer treatment of the bridge waterproof layer adopts the shot blasting process, that is, the surface blasting machine is used to throw the floating slurry on the bridge surface. The surface of the bridge treated with shot blasting is uniform and uniform, the original base structure and flatness remain intact, and the floatation and sanding can be completely removed, 100% “wound surface” and exposed bone; and it will not cause loosening of the aggregate and microcrack. The occurrence of a class phenomenon enhances the adhesion of the waterproof material to the surface and provides a certain degree of penetration.

(2) The base treatment equipment adopts the equipment with synchronous flotation and vacuum cleaning function, and the self-circulating and recycling shot blasting equipment with driving system to carry out the bridge concrete base treatment. The speed of the shot blasting machine is 2-3 gears, the walking speed is controlled at 5-10m/min, and the pellet size is S390.

(3) Before the large-area shot blasting is carried out, the shot blasting test should be carried out to determine the key parameters such as the pellet specification, the flow rate of the pellets and the walking speed of the shot blasting machine. After the shot blasting parameters are determined, large-area shot blasting can be performed, and the cleaning should be taken after the processing is completed.

(4) The shot blasting process should be continuously operated. If the shot blasting machine needs to be temporarily stopped, the machine should be retracted by 30cm before the next shot blasting, and the shot blasting machine should cover the retreating distance. Inspect the shot blasting quality of the covered area in time and properly fill it.

(5) When the concrete leveling treatment is applied to the bridge deck and the root of the protective wall, an angle grinder can be used, and no obvious concave and convex grooves are allowed to appear, so that the surface is flat and the waterproof layer is effectively bonded.

(6) The roughness of shot blasting should meet the requirements. If the roughness is too large, it will bring a lot of primer and repair work, and it is not conducive to the bond strength; if the rough bottom is too small, it will lead to insufficient adhesion. The shot blasting standard should be based on no floating slurry on the spot, and the roughness control should be in SP3.

(7) There are slopes at the beam end and side. The shot blasting machine is easy to leak the pellets, and the loss is very serious. In order to save the cost of shot blasting, it is necessary to recycle the pellets, and the loss of the pellets is required to be within 10%-20%. . Under the premise of not leaking the pellets, the shot blasting machine should be as far as possible, which can greatly reduce the grinding process in the next process, saving time and material loss.

(8) The base defects after shot blasting by the road shot blasting machine are fully exposed, and holes are formed in the concrete bridge deck. The moisture and air present in the holes are heated and expanded after spraying to cause pinholes on the surface of the coating, which affects the apparent quality of the coating. In order to ensure the1 construction quality, the roughness of the base layer can be controlled by adjusting the walking speed of the shot blasting machine to avoid the over-polishing phenomenon, which is inconvenient for subsequent construction. The surface of the base layer is inspected and repaired with repairing putty. Generally, the epoxy mortar is used to repair the putty and smeared for 2-3 times.