Gradation levels are aggregate particle size distribution of the particles can be determined by sieve analysis test. For the mortar with sand, a total of more than 4.75㎜ mesh sieve should be 0, the actual particle size distribution of sand sieve except 4.75㎜ and 0.6㎜ stalls outside, can slightly exceeded, but the total exceeds the sum of the value of more than sieve levels should be less than 5%. Domestic sand is to meet the requirements of the second district in the sand.

 

Great sand of Gradation fresh concrete effects work, but also affect many properties of hardened concrete, such as strength, deformation properties, thermal properties, etc., will also affect the cost of production of concrete. Better aggregate gradation can be prepared in less water consumption and good working conditions for a concrete mix, and to ensure no segregation molding to obtain a homogeneous dense concrete. Both to ensure the quality of concrete construction projects to improve the performance of concrete, but also reduce the cost of the concrete.

 

In the mechanism of sand production, due to the source material lithology regional diversity sand process equipment, production operations are not standardized, resulting in sand particle size distribution in terms of form vary widely, mainly as follows: sand particles oversized high proportion of sand fineness modulus is too large or too small, graded discrete particles 0.6-2.36 or less than normal, the poor stability of particle size distribution and other issues, coupled with concrete or mortar construction requirements different,, sand used to bring some negative effects, is not conducive to the promotion of a wide range of sand, but also to the sand and gravel business equipment business cause greater confusion, tried various ways of sand particles gradation adjustment to optimize and control, hope graded sand can be adjusted to achieve effective control mechanisms become common goal sand and gravel business enterprises, according to the test and production practice, usually through the process, crusher type, material source distribution, and mesh sieve size, fine particles and powder separation several parties gradation adjustment. Below the main factors affecting the production of sand with a particle size of and how to adjust the grading system analysis

 

Sand in the production process, not a wet production process, or dry production process must remove excess powder, the wet production by sand washing machine washing powder through a certain way, but at the same time there are a lot of 0.3mm sand about the loss of fine particles, resulting in the finished sand gradation unreasonable, in dry production, the use of winnowing powder, the same is likely to cause the loss of fine particles must be controlled and fine particles of fine particles sucked in as much as possible to return the system for grading adjusted up but when fine particles are more, you can increase the amount removed in order to meet the requirements of the finished sand grading. So how much must be appropriate to adjust the parameters according to the content of the finished production equipment in the fine sand particles reach gradation adjustment purposes.