In concrete and refractory materials, often use silica fume as admixture, so as to improve the performance of materials, usually in concrete mainly to improve the role of strength, in refractory materials can improve refractory strength and refractory temperature, but sometimes silica fume can not be used alone, then in different application scenarios silica fume and what together is better?
Silica Fume + high efficiency water reducing agent
Silica fume when mixed into the concrete, will fill the pores between the cement particles, increase the density of concrete, has a strong segregation, which leads to a large number of cracks in the concrete later, especially with the increase in the amount of microsilica powder, the more serious this phenomenon, so in the traditional method will be changed by changing the water-cement ratio, so as to reduce the cracks, but this will inevitably change the other properties of concrete use. Therefore, when mixing silica fume, at the same time mixing water reducing agent, can effectively reduce the late cracks in concrete without changing the water-cement ratio.
Silica Fume + fly ash
Although silica fume has the ability to improve the performance of concrete, but alone it is difficult to use concrete to achieve the effect, and fly ash as another concrete admixture, although the ability to improve the strength of concrete is not as good as microsilica powder, but it can effectively improve the construction performance of concrete, so when the two compound, it can make the concrete better performance.
Silica Fume + fly ash and slag powder
Silica fume, fly ash and slag powder compound, the main role is to ensure that the concrete particle gradation, so that the concrete in the pore less, the composition is more dense, especially in the ultra-high strength concrete, a variety of mineral admixtures are required to compound. Slag powder particle size is mainly distributed between 1 to 100μm, concrete with slag powder after grinding, the particle size should be distributed in 5μm, while 80% of the particles of silica fume are in 1μm, the average particle size in 0.1μm to 03μm, they can fill the concrete pores as well as very small pores, so that the strength of ultra-high strength concrete is higher, better seepage resistance and other properties They can fill the larger pores of concrete as well as the very small pores, making the UHPC stronger and more resistant to seepage.
