Application of silicon powder
Silicon powder is characterized by extremely fine particles (average particle size is 0.1um, only a few hundredths of cement particles) and large surface area (15000m2/kg). When silica powder is added to concrete, its functions are as follows:
(1) Physical action. Due to its fine particles, it fills the pores between cement particles, makes the slurry more compact, improves the microstructure of cement and aggregate, and thus improves the macroscopic physical-mechanical properties (strength, impermeability, durability, elastic modulus, etc.) of concrete materials.
(2) Chemical reaction. The major component of silicon powder silica (Sio2) under the condition of alkaline excitation, the precipitation with the cement hydration Ca (OH2) react, generated with hydraulic properties of silicate gel, hydrated calcium silicate gel (also called CSH gel), the gel plugging in the capillary, the capillary pore become smaller, and discontinuity, the compactness of concrete can be enhanced greatly. And the strength of calcium silicate hydrate gel is much higher than that of Ca(OH)2 gel. Therefore, silicon powder has two advantages of volcanic ash effect and particle effect, which can improve the bleeding and cohesion of fresh concrete, and achieve the purpose of comprehensively improving the concrete quality.
