What is the role of microsilica in concrete?
Jun 12, 2024
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After microsilica is added to concrete, it can be fully dispersed and filled in the gaps between cement particles, making the slurry more compact. The volcanic ash activity index of microsilica can reach 110, and the effective substitution coefficient can reach 3-4. In particular, it has a strong absorption capacity for Ca(OH)2 generated after cement hydration, forming a well-developed calcium silicate gel, which greatly improves the strength of concrete.
1. Increase strength: When the addition amount is 5-10%, the compressive strength of concrete can be increased by 10-50%, and the flexural strength can be increased by more than 10%.
2. Increase density: When 10% is added, the impermeability is increased by 5-8 times, and the carbonation resistance is increased by more than 4 times.
3. Increase frost resistance: After 300-500 freeze-thaw cycles, the relative dynamic elastic modulus of concrete mixed with 10% microsilica is reduced by 1-2%, while the relative dynamic elastic modulus of ordinary concrete has been reduced by 36-73% after 25-50 cycles.
4. Increase early strength: The compressive strength of the control group R1 increased by 30%, and R3 increased by 40-50%.
5. Increase abrasion resistance and cavitation resistance: Microsilica concrete has 0.5-2.5 times higher abrasion resistance and 3-16 times higher cavitation resistance than ordinary concrete. It is the best material for anti-wear repair and surface protection of hydropower stations, reservoirs and dams.
