foreign plugging concrete delivery

In theory, the most prone to plugging in three large stones in the same section meet clamping, the time section occupied most of stones, negotiable area is very small. Usually provides concrete mixing machine gravel d: D <1:3 (Note: This is the "order" in the detailed provisions, according to the transport height and stones kind of 1:2.5 to 1:5), and the pump hopper located on the square grid, to prevent oversized stone in mixed. When passing 0.315mm sieve sand content is low, even if the concrete other technical indicators are in line with requirements will be plugging. Because these sand in concrete balls from a similar role to reduce the friction with cement mixing machine, to improve mobility in vain, increase the cohesion into water retention, pumpability of concrete greatly. Therefore JGJ/T10-95 "Technical Specification for Concrete Pumping" in the provisions of the sand through the 0.315mm sieve not less than 15%.