Concrete: cement: water: sand: stone ratio = 1: x: y: z, the water content of field sand is m, and the water content of stone is n, so the construction mixture ratio is adjusted to:1:(x-y * m-z * n): y * (1+).

The mix proportion of concrete is determined according to the quality and moisture content of cement, gravel and sand. Concrete grades are divided into C 15, C20, C25, C30, C35, C40, etc. The larger the number, the higher the intensity. The general specification requires that the floor concrete should not be lower than C20 and higher than C40, because the higher the concrete strength, the more brittle it is.

Basic requirements of concrete mix design:

(1) meets the design strength grade of concrete.

(2) The workability of concrete that meets the construction requirements.

(3) Durability meets the use requirements of concrete.

(4) Under the above conditions, save cement and reduce the cost of concrete.

Principles of concrete mix design:

(1) The workability of concrete mixture can meet the construction needs.

(2) The concrete strength can meet the design requirements.

(3) Concrete should have good durability.

(4) In the case of meeting the above requirements, try to reduce costs and increase benefits.