10 important functions of silica fume in concrete

Silica fume can fill the pores between cement particles, and at the same time form a gel with the hydration product, and react with the alkaline material magnesium oxide to form a gel. Adding an appropriate amount of silica fume to cement-based concrete, mortar and refractory castables can play the following roles:

1. Significantly improve the compression resistance, flexural resistance, impermeability, anti-corrosion, impact resistance and wear resistance.

2. It has the functions of water retention, preventing segregation and bleeding, and greatly reducing the resistance of concrete pumping.

3. Significantly prolong the service life of concrete. Especially in harsh environments such as chloride pollution erosion, sulfate erosion, high humidity, etc., the durability of concrete can be doubled or even several times.

4. Significantly reduce the ground dust of sprayed concrete and castables, and increase the thickness of a single spray layer.

5. It is a necessary component of high-strength concrete, and has been used in engineering applications of C150 concrete.

6. It has about 5 times the effect of cement, and it can reduce costs and improve durability when used in ordinary concrete and low-cement castables.

7. Effectively prevent concrete-alkali-aggregate reaction.

8. Improve the compactness of castable refractories. When it coexists with Al2O3, it is easier to form mullite phase, which enhances its high temperature strength and thermal shock resistance. 9. It has a very strong volcanic ash effect. When mixing concrete, it can undergo secondary hydration reaction with cement hydration product Ca(OH)2 to form a gelled product, fill the cement stone structure, improve the microstructure of the slurry, and increase the Mechanical properties and durability of hardened bodies.

9. Silica fume is amorphous spherical particles, which can improve the rheological properties of concrete.

10. The average particle size of silica fume is relatively small, which has a good filling effect and can be filled in the gaps of cement particles to improve the strength and durability of concrete.