What Are The Commonly Used Concrete Admixture Minerals

Common mineral admixtures for concrete are: fly ash, granulated blast furnace slag, silica fume, limestone powder, steel slag powder, phosphorus slag powder, zeolite powder, and composite mineral admixtures.

Adding mineral admixtures to concrete can improve the mechanical properties of hardened concrete, improve the workability of mixing concrete, and improve the durability of concrete.

Under the premise of improving the performance of concrete, the admixture in the mining area can replace 30% to 50% of the cement, greatly reducing the amount of cement. 

The adsorption of water by the particles on the surface of the mineral admixture plays a role in water retention and significantly improves the cohesion. 

Concrete mixed with mineral admixtures can form a relatively dense structure, and significantly improve the bleeding properties of fresh concrete, avoid the formation of connected capillary pores, and improve the impermeability of concrete.

Advantages And Disadvantages Of Mineral Admixtures In Concrete

Fly ash has small shrinkage and good crack resistance, but has low chemical activity, low early strength and poor carbonization performance.

The chemical activity of slag powder increases significantly with the increase of the surface area, the carbonization performance is slightly better, but the shrinkage is large, and the crack resistance is poor. When the surface area is too large, it is not conducive to the control of concrete temperature rise.

Silica fume can improve the early and late strength of concrete, but it has large self-drying shrinkage and is not conducive to reducing the temperature rise of concrete.

Limestone powder can significantly reduce the viscosity of the fluid, but when the component is in a corrosive environment containing sulfate, in the presence of water and the temperature is lower than 15 ℃, it will generate non-gelling wollastonite gypsum to soften the concrete.