Slag cement (Slag cement) is also called slag portland cement. It consists of Portland cement clinker, 20% -70% granulated blast furnace slag, and an appropriate amount of gypsum. Slag has become an important mixture of cement, but the abrasiveness of slag is very poor, so it is important to choose an appropriate process. The common grinding, separate grinding, mixed grinding, and combined grinding processes based on roller presses are analyzed and compared respectively. It is considered that pre-milling of slag with a roller press can improve cement quality and save energy. The selection of classification equipment in the grinding system is also important.
Technical indicators: GB / T 18046-2008
level
S105
S95
Density / (g / cm3)
2.8
Specific surface area / m2 / kg
500
400
Activity index /%
7d
95
75
28d
105
95
Flow ratio /%
95
Water content
1. Can prepare high strength and high performance concrete.
2. Slag superfine powder concrete has good water retention, good plasticity, less bleeding, and has better workability.
3. Reduce the heat of hydration, which is helpful to prevent cracks caused by temperature rise inside the large volume concrete.
4. Generate more ettringite crystals to compensate for dry shrinkage caused by too much fine powder in the concrete.
5. Hardened concrete has good resistance to sulfate attack, reducing and inhibiting the diffusion of chloride ions, resistance to seawater erosion, resistance to carbonization, and resistance to alkali-aggregate (aggregate) reactions.
6. Improve the durability, abrasion resistance and economy of hardened concrete [2]
Compared with ordinary concrete, slag ultra-fine powder concrete has a higher late-term growth rate, and lower shrinkage and creep values. Superfine slag powder can optimize the concrete pore structure, improve the permeability resistance, reduce the chloride ion diffusion rate, reduce the Ca (OH) 2 in the system , inhibit the alkali aggregate reaction, improve the resistance to sulfate corrosion, and improve the durability of concrete improve. Large amount of superfine ore powder can reduce the thermal peak and delay the peak temperature occurrence time. Freshly mixed slag powder concrete works well, the slump loss over time is reduced, it is easy to vibrate, and the bleeding is low [2]
Used for ordinary concrete, various high-grade, high-performance concrete and cement products to replace the amount of cement in order to improve the durability of concrete and cement products in various harsh environments. Adding super fine powder such as slag can improve the compactness of concrete and cement products, and its later strength is high, which reduces the cost of concrete and cement products [3]
1. It is used in high-strength, ultra-high-strength, high-performance concrete and prefabricated ready-mixed rods, pipes, large bridges and other industries, with high strength and smooth surface.
2. It is used in marine projects eroded by seawater, docks, reservoirs and tunnels.
3. Basic engineering used in various environments.
4. Used in highways, airport runways, heavy-duty vehicle road engineering, etc. [3] .
