Dec 20, 2018
As we all know, the raw materials of concrete are generally composed of sand and gravel aggregates and cement, fly ash and other powder materials. Knowing about the characteristics and properties of various raw materials is helpful to operate the concrete mixing plant equipment correctly.
The gradation of the aggregate is good and its workability is good;the sand is coarse and the workability is not good; the work of the pebbles is good, and the needle-like stones are more, and the workability is poor. Sand rate is the percentage of sand and gravel aggregate weight in concrete. When the sand ratio is too small, the concrete is bleeding and segregating. When the sand ratio is too large and the amount of cement is small, the workability is deteriorated.
The finer the fineness of cement, the lower the water secretion and the better workability; when the amount is too much, the shrinkage of the cement increases. The water-cement ratio refers to the weight ratio of water to cement in concrete. If the ratio is large, the workability is good. However, if the water is too much, isolation and bleeding will occur, and the strength will be greatly reduced. Therefore, the water consumption of the concrete must be strictly controlled. In the case where the water-cement ratio is constant, an appropriate increase in the amount of cement slurry can improve workability.
