(1) When installing and designing pipes, try to avoid 90. And s-bends. Try not to use pump pipes with obvious pits to reduce the resistance of pumping concrete and prevent blockage. The pump pipe shall be checked frequently. If the wear degree of the pump pipe in one direction is large, the pipe shall be replaced in time. If the thickness of the pump pipe is too thin, the new pipe shall be replaced in time to prevent the pump pipe from exploding during the working process or pipe blockage caused by the long time of replacing the pump pipe.
(2) In order to ensure the continuity of pumping concrete operation and the quality of concrete pouring, the interval between operations should not be too long to prevent blockage. If the interval is long for some reason, start the pump or reverse or forward pump several times every 20 minutes or so, and turn on the circulating pump if necessary to prevent blockage.
(3) The pumped concrete shall meet the pumpability requirements. If necessary, the mix proportion of pumped concrete shall be determined through pump test. Firstly, the ratio of the maximum particle size of coarse aggregate to the conveying pipe diameter shall be determined. When the pumping height is below 50m, it should not be greater than 1:3 for gravel and 1:2.5 for pebble; When the pumping height is 50 ~ 100m, it should be in the range of 1:3 ~ 1:4; When the pumping height is more than 100m, it should be between 1:4 and 1:5. The content of needle flake particles should not be greater than 10%. 3.3.2 for different pumping heights, the slump of man pumped concrete can be selected according to (as shown in Table 1).
