With the rapid development , on the one hand, it faces a shortage of energy and raw material resources, on the other hand, it emits a large amount of waste, of which mineral waste slag accounts for a large proportion.
If these mineral waste residues cannot be used effectively, it will cause huge waste of resources, occupy a large amount of land, and cause great harm to the environment and people’s health.
Prestressed high-strength concrete pipe piles are currently the main pile foundation materials, but the traditional steam curing + pressure steaming secondary hydrothermal curing process consumes high energy, complicated technology, and high equipment and production costs, which affect the sustainable development of the pipe pile industry.
Utilizing industrial solid waste: mixed grinding of slag, slag, and fly ash, which can be used to prepare high-strength concrete admixtures for pipe piles, which not only realizes the recycling of solid waste, but also saves production costs and improves economic benefits. The research found when slag: fly ash: slag=5:2:1 and slag: fly coal When ash=2:1, mineral admixtures can produce high-strength mortar and concrete.
Then, how to prepare high-strength concrete admixtures for pipe piles such as slag, slag, steel slag, and fly ash to realize recycling and reflect economic value? The more critical link is the grinding link of the admixture. The grindability of the slag is poor.
The slag grinding technology determines its quality and output. The use of slag powder in cement production is directly related to the grinding technology and the activity of the slag powder. The pipe pile concrete is mixed with slag. The ratio is related to the activity of the slag powder. The higher the activity, the higher the blending ratio, and the strength of the pipe pile concrete produced can reach the standard.
Studies have shown that physical activation can well activate the activity of slag, mainly because the slag is easier to grind, but the high carbon content of the slag seriously affects the performance of the slag; physical activation can also improve the activity of fly ash.
However, if the grinding time is too long, the increase in activity is not obvious; the physical stimulation does not increase the activity of steel slag very much, mainly because the steel slag is difficult to grind
In the traditional production process, ball mills, rod mills and other equipment are often used for the grinding of admixtures, and the fineness cannot be adjusted and controlled. Some steel slag powder production processes require secondary grinding, which is prone to over-grinding, high energy consumption, The process is complicated, the equipment cost is high, the noise is high, and the pollution is large.
It is understood that pipe pile concrete companies generally believe that the most economical grinding fineness of slag powder should be controlled at about 400m2/kg, which is more common in the production of S95 slag powder. Shibang slag vertical mill, also called vertical roller press, can process fineness ≥420 m2/kg. From the analysis of the grinding mechanism of the roller press and the characteristics of the slag, the vertical roller press is suitable for grinding the slag.
This is because the vertical roller press belongs to the restricted extrusion of the material bed, and the slag is also a brittle material. The characteristics of using a vertical mill to prepare mineral powder are:
(1) High grinding efficiency and low power consumption;
(2) It integrates drying and grinding without additional drying system. The process is simple and the floor space is small;
(3) The technical requirements are high, and the main equipment investment is high.