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How Does Silica Fume Improve The Frost Resistance Of Concrete?

silica fume concrete in highway

The chemical composition of silica fume is silicon dioxide (SiO2), which is an inert substance and does not react chemically with most acids and alkalis.

Silica fume has great use in water conservancy, highway and bridge projects. Concrete has very harsh requirements for abrasion resistance, scour resistance, corrosion and frost resistance, so it is very necessary to mix micro-silica fume. Silica fume can be evenly distributed and covered on the surface of the object, effectively improving the frost resistance of concrete. So, how does silica fume improve the frost resistance of concrete?

The silica fume accumulation density is small

Silica fume as a polymer filler material, less than other mineral filler products, loading weight is small, saving the amount of polymer, so it can reduce the cost of concrete products, improve the degree of hydration of the cement, and Ca (OH) 2 secondary hydration reaction, increase the number of hardened cement paste in the C-S-H gel, to improve the performance of the traditional C-S-H gel, so as to improve the performance of concrete.

The relative elastic modulus of silica fume is small

Silica fume after 300-500 cycles of rapid freezing and thawing, the relative modulus of elasticity is lowered by 10-20%, while the relative modulus of elasticity of ordinary concrete is lowered by 30-73% through 25-50 cycles. Therefore, it can be seen that silica fume can effectively improve the frost resistance of concrete. Silica fume and its secondary hydration products to fill the harmful holes in the concrete, cement stone in the macroscopic macroporous and capillary pore porosity is reduced, while increasing the gel holes and transition holes, so that the distribution of pore size changes greatly, the reduction of macroporous, small holes increased, and uniform distribution, thus changing the pore structure of concrete, improve the frost resistance of concrete.

Small particle size of silica fume particles

Due to the small particle size of silica fume, the average particle size of about 0.1μm, about 1/100 of the particle size of silicate cement particles, at the same time, the specific surface area of silica fume is very large, the specific surface area of silica fume determined by nitrogen adsorption method is up to 20m2/g, so the silica fume is very easy to form a group, so it can be used as a nucleus required for the hydration of the cement when the cement hydration, so as to accelerate the hydration of the cement. At the same time, due to the fine particles of silica fume, it can fill the small pores in the concrete and reduce the porosity of the cement paste, which in turn makes the concrete denser and stronger, and at the same time, enhances the performance of the concrete to resist the deformation of the external force, so as to minimize the creep and dry shrinkage of the concrete.

In addition, on the storage of silica micropowder, it is recommended that it should be stored in a dry, rain-sheltered, sun-shaded environment. Silica fume caking activity loss in water. Prohibit prolonged exposure to sunlight, so as to avoid bag weathering, product spillage.

HSA Silica fume

HSA has been a global supplier of high-quality silica fume since 2001. We have established long-term and stable cooperation with many concrete construction companies around the world to provide our customers with high-quality silica fume with different contents and different uses, fully satisfying all kinds of concrete project needs.

If you have any needs for silica fume, please feel free to contact us!


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