The concrete mixture, as a rule, is prepared for concrete plants and transported to the construction of specialized vehicles. Where necessary, preparation of concrete can be organized in betonorastvornyh nodes directly on the site. Concrete plants and concrete units on site storage consist of cement, sand and gravel (or gravel), metering devices, concrete mixing machines and bins for ready-mixed concrete. [...]
The degree of mobility of the plastic concrete mixtures evaluated using a standard cone, which is placed in the concrete mix. After removing the concrete form under its own weight settles, the value of precipitation in mm characterizes the mobility of the concrete mix. The mobility of the concrete mix transported by conveyor belts with the largest angle conveyor belt when lifting 15 °, and during the descent, 10 ° should not exceed the slump - [...]
Distinguish mobile (plastic) of a mixture that can be packed into the formwork and compacted under its own weight, and tough, requiring for their sealing application of external forces (vibration, vibroshtampovanie, vibroprokat). Hard mixtures contain a limited amount of water, mix with the great richness of different coarse aggregate (crushed stone or gravel). The use of harsh concrete mixes improves concrete strength, more efficient use of cement [...]
The concrete mixture should have properties that provide the specified concrete strength. The concrete mixture shall meet the following requirements: save during transportation, handling and stacking of shuttering its homogeneity, achieved with stirring; have proper consistency, good ability to be molded and compacted to possess workability for fast and dense filling of the formwork, all the spaces between reinforcing bars.
