Classification and application fields of slag powder

According to the activity index, slag powder can be divided into three grades: S75, S95 and S105. The higher the number, the higher the grade, which means that its activity is better and its strength is better when used as cementitious material.
At present, there are certain regional differences in the use of slag powder in China, but most areas use S95 grade slag powder, which is commonly known as "95 powder". Some marine projects use high-grade slag powder to configure high-performance concrete, and add slag powder to improve the pore structure of concrete, improve the permeability of concrete to chloride ions, and have excellent durability. For example, the Hong Kong Zhuhai Macao Bridge, as well as some other large-scale projects: Taishan nuclear power project, Macao Hengqin subsea tunnel, Beijing Xiong City railway.

Slag powder can be used not only as an independent product in the construction market, but also as a mineral admixture in concrete and mortar. It is common in the market to use slag powder to replace part of the cement in the ready mixed concrete and cement products in the same amount or in excess. The specific amount varies according to the different projects, and the approximate range is 20% - 70%. Moreover, the carbon emission of mineral powder is very low, which is supported by research data. For each ton of slag powder used to replace Portland cement, the carbon emission of 0.77 tons can be reduced, and the comprehensive emission is less than 10% of that of cement.