The role of silica fume in cement
keywords
Silica fume, microsilica, silica ash, cement, concrete, amorphous silica, volcanic ash activity, shotcrete ash
Profile and features
Silica ash is the dust discharged by ferrosilicon alloy factory or silicon steel plant when producing ferrosilicon and silicon steel. The dust recovered after electrostatic dust removal is mainly amorphous SiO2, and the particle size is generally less than 0.1 um, which has high volcanic ash activity, and is mainly used in high strength and high performance concrete.
Mechanisation
In terms of working performance, the spherical morphology of silica ash can make it fill the partial space between cement particles, replace the partial filling water between cement particles, and improve the fluidity of concrete. Silicon ash can fill the pores between the cement particles, while forming a gel with the hydration products, and react with the alkaline material magnesium oxide to form a gel. But the silica ash particles are too fine, resulting in large water demand, when a certain amount of the concrete mix will become sticky.
High activity
The particle fineness and chemical composition of the silica ash lead to its high volcanic ash activity. The high activity of silicon ash is very beneficial to the development of early and late strength of concrete. Its very fine particles can produce good fine filling effect, make the concrete hole structure more dense, improve the mechanical properties and durability of concrete, and also inhibit the alkali aggregate reaction.
Performance advantage
Significantly improve the compression resistance, folding resistance, seepage resistance, corrosion resistance, impact resistance and wear resistance performance.
It has the function of retaining water, preventing segregation, drainage, and greatly reducing the resistance of concrete pumping.
Significantly prolong the service life of concrete. Especially in the chlorine salt pollution erosion, sulfate erosion, high humidity and other harsh environment, the durability of concrete can be doubled or even several times.
Reduce the floor ash of shotcrete and cast material, and improve the thickness of a single spray layer.
Improve the tightness of pouring-type refractory materials. When coexisting with AI203, it is easier to generate mollite phase, which makes its high temperature strength and thermal vibration resistance enhanced.
