Concrete pumping refers to the process that concrete is delivered to the construction sites by pump, and the slump is not less than 100mm. Concrete pumping can be a continuous horizontal transport and vertical transport, which has the advantages of high efficiency and low costs. However, what are the precautions when pumping concrete? We Aimix Group think that users should pay more attention to cement, aggregate, admixtures, slump and mixing ratio when pumping concrete.
Users should choose ordinary cement, slag cement and fly ash cement for pumping concrete, and users should choose limestone cement.
The needle flake content of the aggregate should not be more than 10% for pumping concrete. In general, the aggregate should be used in the sand, and the particle size through the 0.315mm sieve should not be less than 15% while the particle size through the 0.160mm sieves should not less than 5%.
Pumping concrete should be mixed with pumping agent or water reducing agent, and it should be mixed with fly ash or other active admixtures to improve the pumping ability of diesel concrete mixer pump.
In the process of pumping concrete into the pump, when the pumping height is less than 30 meters, the collapse should be 100 to 140 mm. When the pumping height is about 30 to 60 meters, the collapse should be 140 to 160 mm. When the pumping height is 60 to 100, the collapse should be 160 to 180 mm. When the pumping height is 100 meters or more, the collapse should be 180 to 200 mm.
The water-cement ratio of pumping concrete should not be greater than 0.60, and the total amount of cement and mineral admixtures should not be less than 300kg / m3. Practice has proved that this can significantly improve the work-ability and save cement after pumping concrete is mixed with fine grinding of fine fly ash and slag.