1) concrete pumpability. Pumping concrete pump shall meet the requirements may be necessary, pumping should be determined through trial and pumping concrete mix.
① The maximum size of coarse aggregate and conveying the ratio of diameter should be: pumping below 50m in height, the stone should not be greater than 1:3, for the pebbles should not be greater than 1:2.5; pumping height at 50 100m, should be in the range of 1:3 ~ 1:4; pumping height of 100m above, should be between 1:4 ~ 1:5. Flakiness particle content of not more than 10%.
② different pumping heights into the slump of the concrete pump can be used as follows.
Pumping height (m) 30 less than 30 ~ 6060 ~ 100100
Slump (mm) 100 ~ 140140 ~ 160160 ~ 180180 ~ 200
③ desirable for pumping concrete water-cement ratio (0.4 ~ 0.6): 1.
④ sand ratio of pumping concrete should be 38% to 45%. Should be adopted in the sand fine aggregate, sand sieve through 0.315m amount not less than 15%.
⑤ minimum cement pumping concrete content 300kg/m3.
(2) Concrete pump starts pumping should be adequate water to wet concrete pump hopper, concrete tanks and pipes and other parts directly in contact with the concrete. Pumping water and then one of the following methods used lubricating these parts: pumping cement slurry; pumping cement mortar 1:2; pumping than other adults outside of coarse aggregate distribution and the ratio of cement mortar.
Lubricated with a water slurry or cement mortar should be spread cloth, not focused on pouring in the same place.
(3) start pumping, the concrete pump should be in a slow, constant speed running state, then gradually speed up. Should be observed while the pressure of concrete pumps and work the system until the system is working properly pumped back to normal speed.
(4) work as continuous concrete pumping, concrete cylinder piston stroke should remain in operation, in order to play the largest concrete pump performance, and make concrete cylinder in the length of the wear and tear on the uniform.
(5) If there is concrete pump pressure is too high and unstable oil temperature increased. Pipeline and pumping difficulties apparent vibration phenomenon, not forced pumping, should be excluded immediately identify the cause. Be the first pipeline was struck with a mallet bend. Conical tubes and other parts, and to slow or reverse the pump pumping to prevent clogging.
(6) When the blockage should be taken to exclude the following methods:
① repeated anti-pump and the pump is running, gradually return to the concrete suction hopper, the mixing and re-pumping.
② The mallet percussion and other methods to identify blocked site, to be repeated after concrete counter hit song pumps and pump operation is to eliminate congestion.
③ When the above two methods are ineffective, should be opened in the concrete block after unloading site, to be re-clog pumping discharge.
(7) should adopt the ready-mix concrete pumping concrete can also be set in the field supply pumped concrete mixing station, but no hand mixing of concrete pumping. The supply of concrete should be strictly controlled, and pay attention to changes in the slump of the concrete does not meet the pumping requirements are not allowed into the pump, concrete pump to ensure the effective work.
(8) should be set on the concrete pump hopper screen, and let someone watch the feed, to avoid too large in diameter aggregate or foreign matter caused by congestion.
(9) pumping, the hopper of the concrete position of the stock can not be less than the shaft to prevent air entering the pipe vibration caused by the pump tube.
(10) when the concrete pumping process needs to interrupt, the interrupt time should not exceed 1h. And should be every 5 ~ 10min anti-pump and pump operation is to prevent the pipeline due to bleeding or the slump loss of concrete too large plugging.
(11) pumping has been completed, must be carefully cleaned hopper and pipeline systems. Residual concrete concrete cylinder is not clean, if cleared, will cure the cylinder wall, when the piston is run again, the piston sealing surface on the cylinder wall directly under the concrete has been cured of their impact, leading to partial spalling push the piston. The damage is different from the normal wear and tear piston seal, the sealing surface can not be under pressure, self-compensation, leading to leakage of plasma or suction air, causing pumping weakness, blockage.
(12) when the concrete can be poor or concrete pump bleeding occurs, segregation is difficult to pump, you should immediately mix, concrete pumps, piping and pumping process were studied, and take appropriate action to resolve.