How to Deal With The High Content of Stone Powder in Machine-made Sand?

2021-11-06

The machine-made sand will inevitably produce a large amount of stone powder in multiple production processes such as crushing, screening, and sand making. A proper amount of stone powder can increase the strength of concrete under the action of hydration, and reduce the risk of segregation and bleeding of the mixture. However, if the content is too high, it is not conducive to the bonding of aggregate and cement stone, which will reduce the performance of concrete. So how much stone powder content in machine-made sand should be controlled? What should I do if the stone powder content is high?

What should be the stone powder content in machine-made sand?

Stone powder in machine-made sand refers to particles with a particle size of less than 0.075mm. If the machine-made sand contains an appropriate amount of stone powder, it is beneficial for its use. However, there are strict requirements on the content of the powdered stone. Generally, the content of powdered stone is ≤5.0% for type I sand, ≤7.0% for type II sand, and ≤10.0% for type III sand. When it is used for pumping concrete, it must contain a certain amount of stone powder in order to achieve good workability. Generally speaking, a stone powder content of 10% to 14% is appropriate. For C30 concrete, the stone powder content is 10-15%. For C50 concrete, the stone powder content is 5-10%.

How to deal with the high content of stone powder in machine-made sand?

1. Use the sand washer

After being crushed by the crusher, the material enters the vibrating screen for screening. The under-sieve can be cleaned by the sand washing equipment in the lower section. The sand washing machine can clean the excessive stone powder, soil, and impurities in the machine-made sand. It has the characteristics of a good cleaning effect, less loss of medium and fine powder, and small water consumption.

2. Arrange stone powder storage yard

A stone powder storage yard should be considered in the general construction layout. The storage yard can not only adjust the addition amount, but also reduce the moisture content through natural dehydration, and adjust the moisture content of the finished sand to a certain extent.