what is the standard silica fume quality
What is the standard for silica fume quality? Today, Anyang Huatuo Metallurgy will share this questions. The higher the SiO2 content is, the higher the performance of the silica fume is, and the lower the content of other non-SiO2 impurities. The content of micro silica powder is ＞85%, and the carbon of micro silica powder contains adsorbing part of air en-training agent in concrete. In addition, the fineness of the micro silica powder should be controlled at 45μm, the particles are large and the sieve component is below 10%. Therefore, the micro silica is an ultra-fine powder material. The reason why micro silica can improve the strength of concrete. The key point, the micro silica can improve the bond strength between the cement paste and the aggregate as well as reduce the fresh water, prevent the water from accumulating on the lower surface of the aggregate to increase the density of the interface transition zone and reduce the thickness of the interface transition zone.
The micro silica powder has a particle size 100times smaller than the cement particles, and micro silica is filled between the voids of the cement particles.The effect is just as the cement particles filled between the aggregates so as to increase the compactness of the concrete. However, one of the prerequisites for silica fume quality is good dispersion in concrete in these effects. Micro silica powder, adding a small amount into the concrete, combines with the super-plasticizer to improve the physical and mechanical properties. For example, it can reduce the segregation and bleeding of concrete significantly, improve the pumping performance of concrete and the early and late strength of concrete effectively, reduce the penetration of chloride ions, improve the chemical corrosion resistance and wear resistance of concrete effectively. Underwater construction, the concrete is kept out of separation.
Practice has shown that ordinary concrete projects may be severely damaged in a short period of time in a harsh environment. It is easy to threatening the quality of the project and reduce the service life of the project greatly. The high-performance concrete adopting with cement, silica fume, fly ash and alkaline water agent compounding can meet all requirements has been successfully applied in various projects, which promote the advancement of shotcrete technology, reduce the efficiency of injection rebound, improve the construction efficiency, improve the concrete performance significantly. What is important, the high performance concrete let the flexibility, speed and economics of concrete construction raise a new level.