According to the various data provided by the concrete mixing station, I summarized some experiences and lessons in the application of pumping commercial concrete to block pumps and pipes, and hope to help you concrete friends. The characteristics of pumped concrete are uniform material quality, stable quality, and fast feed speed. It can continuously complete vertical and horizontal transportation at one time, with high production efficiency and labor saving. Because the delivery pump is transported and poured along the pipeline, the pipeline clogging is a worrying thing for pumping concrete.
Question: What is the reason why it is easy to block the pipe when pumping concrete into the deep foundation pit with a tow pump? What measures should be taken?
Answer: When the depth of the deep foundation pit exceeds 5m, the concrete mixture in the inclined pipe section from the ground to the bottom of the pit is subjected to a large downward gravitational force, which causes the mixture to move downward, and the gas in it forms upward to the bend Air blockage. A 180 ° elbow can be installed at the lower end of the inclined pipe section to solve the pipe blocking problem; an exhaust valve can also be installed at the upper end of the lower elbow to solve the pipe blocking problem.
Question: If the pumped concrete is of low grade, is it difficult to beat? Because a batch of orders were received at the near station, it was a cushion. The C20 was used. The pump driver reflected that it was not easy to hit. When I went to the construction site to see it, I found that the pump was very difficult to play. Because of the small amount of cement used in concrete, the cohesion is not very small. In addition to the use of fine stones, there are too many stones, so it is not easy to beat?
Answer: It may be that your mix ratio design is not reasonable. The low-strength pumped concrete mix ratio design should use "double-mixed" mineral materials, that is, a large amount of slag powder and fly ash are mixed at the same time to make the concrete powder Relatively large, which is particularly advantageous for pumpability.
The workability, fluidity, and pumpability of pumped concrete with "double-mixing" low-strength grades have been improved. At the same time, the 28d compressive strength of concrete can meet the design requirements and is within a reasonable range, saving more than ordinary concrete Cement reduces costs, and concrete is easy to vibrate, uniform, and durable. C25 and C20 also use the "double admixture" method to make the lining concrete achieve better economic benefits and quality effects.
If the raw materials can be selected, the effect will be better, such as using low-grade cement, graded sand and gravel, and using admixtures with good adaptability to cement. In addition to increasing the amount of cement, the adjustment on the basis of raw materials is to let the water reducer manufacturers come up with a way. They will adjust and improve according to your situation when preparing the reducer.