mechanism of action of silicon powder in concrete-pg电玩城

in concrete, internal bleeding is blocked by aggregate particles and accumulates under the aggregate to form a porous interface. more ca(oh)2 is formed in the filtration zone of the aggregate interface than in other regions. the ca(oh)2 crystal grows larger and has a stronger orientation parallel to the aggregate surface. large ca(oh)2 crystals parallel to the aggregate surface are more susceptible to cracking and weaker than hydrated calcium silicate gel (c-s-h). the interfacial filtration zone between the cement slurry and the aggregate becomes a weak zone of strength inside the concrete due to the porous and large ca(oh)2 crystals aligned. in hpc, due to the incorporation of a certain amount of micro-silica powder, its strength is significantly improved compared with ordinary concrete (no silicon powder).

   the average particle size of the produced silicon powder is 0.1um, which is only a few percent of the average particle size of the cement. after being mixed with cement concrete, it can be well filled in the voids of the cement particles to make the slurry denser. the silicon powder also has a pozzolanic reaction. after the silicon powder contacts the mixing water, the silicon-rich gel is first formed and the water is absorbed. the gel accumulates between the cement particles which have not been hydrated, and gradually wraps the cement particles and hydrates the product ca ( oh) 2 reacts with the surface of the above silicone gel to form a c-s-h gel having a higher gel strength than ca(oh) 2 crystals. the production of c-s-h gel is mostly in the pores of cement-hydrated c-s-h gel, which greatly increases the structural density of concrete. therefore, it has excellent pozzolanic effect and particulate effect, which can improve the bleeding and cohesiveness of fresh concrete.

  the main functions are as follows: 1 increase the strength: use silicon powder instead of part of the cement to add to the concrete, increase the density and cohesion, so that the concrete compressive and flexural strength is greatly enhanced, blending 5%~10% silicon powder, compressive strength it can be increased by 10% to 30%, and the flexural strength is increased by more than 10%. 2 increase the density: silicon powder can be uniformly filled in the voids of cement particles, making the concrete more dense, overcoming the common voids of concrete, testing the water permeability and carbonization depth, the results show that the impermeability can be improved by 5~ 18 times, the carbonization resistance is increased by 4 times or more. 3 frost resistance: the test shows that the silica fume concrete undergoes rapid freezing and thawing cycles of 300 to 500 times, and the relative dynamic elastic modulus is reduced by 1% to 2%, while ordinary concrete only passes 25~. 50 cycles, the relative dynamic modulus decreased by 36% to 73%. 4 early strength: after the silica powder is added to the concrete, it combines with the free ca(oh)2 to reduce the concentration of ca 2 and oh-, shorten the induction period, promote the hydration of c2s, and show that the silicon powder makes the concrete stronger. the characteristics, there is information, silicon powder can increase the strength of concrete by 30% in 18 hours. 5 anti-wearing and anti-cavitation: more than 60% of china's hydraulic structures are damaged by various degrees of erosion and cavitation. tests have shown that silica fume concrete is 0.5 to 2.5 times more resistant to ordinary concrete and 3 to 16 times more resistant to cavitation.