Microsilica powder, also known as silica fume, is formed at high temperature with oxidation. The particles are very fine, shaped as glass spheres under the microscope, amorphous and amorphous, with excellent physical and chemical properties.
Role of Silica fume powder in concrete:
Silica fume mixed into concrete can be fully dispersed and filled between the gaps of cement particles, making the paste more dense, silica fume volcanic ash activity index of up to 110, effective substitution factor of 3-4, dragon its is a strong absorption of Ca (OH) 2 generated after hydration of cement, the formation of a well-developed calcium silicate gel, greatly improving the strength of concrete.
1. Increase the strength: When the amount of admixture is 5-10%, the compressive strength of concrete can be increased by 10-50% and the flexural strength by more than 10%.
2. Increase density: When mixed with 10%, the impermeability will be increased by 5-8 times, and the anti-carbonation ability will be increased by more than 4 times.
3. Increase frost resistance: Concrete mixed with 10% microsilica powder has a 1-2% reduction in relative dynamic elastic modulus after 300-500 freeze-thaw cycles, while ordinary concrete has a 36-73% reduction in relative dynamic elastic modulus after 25-50 cycles.
4. Increase early strength: The compressive strength of R1 in the control group is increased by 30%, and that of R3 is increased by 40-50%.
5. Increase anti-abrasion and anti-cavitation: Silica fume powder concrete is 0.5-2.5 times more resistant to abrasion and 3-16 times more resistant to cavitation than ordinary concrete. It is the best material for hydropower stations, reservoirs and dams for anti-abrasion repair and surface protection.