What is silica fume? Silica fume is a high value-added by-product of smelting industry silicon and ferrosilicon. It is often used in refractory materials and cement concrete as well as grouting and mortar. Micro-silica powder has pozzolanic reaction in concrete, silicon-rich gel formed by...Send InquiryChat Now
What is silica fume?
Silica fume is a high value-added by-product of smelting industry silicon and ferrosilicon. It is often used in refractory materials and cement concrete as well as grouting and mortar. Micro-silica powder has pozzolanic reaction in concrete, silicon-rich gel formed by hydration of micro-silica powder, higher strength than Ca(OH)2 crystal, and cement. The hydrating gel CSH works together.
Micro-silica powder has relatively high activity, and micro-silica powder is used in cement concrete to fill particle voids, increase bulk density, increase strength and reduce porosity, and play the role of water reduction. This is the working principle of micro-silica powder.
Silica fume in grouting
Silica fume has many good effects on the performance of the grout. The beneficial effects of amorphous and very fine silica fume on high performance grouting are manifested in both physical and chemical aspects: function as ultrafine filler; nucleation in early hydration and high pozzolanic activity.
1. Accelerate the hydration of the cementitious material system
Effect of silica fume on hydration heat release of cementitious materials
2, improve the strength of the grout
When silica fume is used together with high-efficiency water reducer, silica fume reacts with hydration product Ca(OH)2 to form hydrated calcium silicate gel, which fills the gap between cement particles, improves interface structure and adhesion, and forms compact Structure, which significantly increases the strength of the grout. Generally, the amount of silica fume is 5%~10%, and it can be equipped with ultra-high strength grouting material with compressive strength of 100MPa.
3, increase the density
The silica fume particles are very small and can be packed in the gaps between the cement particles. The dense packing of particles can reduce bleeding and reduce the pores and average pore size of the high-strength non-shrinkage grouting. When the amount of silica fume is 5%~10%, good doping effect can be obtained. Water reducing agents should be used to ensure dispersion of silica fume and cement.
4. Improve grout separation and bleeding performance
5. Improve the impermeability and chemical resistance of the grout
6. Effect of silicon powder on frost resistance of grouting slurry
Regarding the influence of silicon powder on the frost resistance of grouting material, a large number of studies at home and abroad have shown that in the case of equal substitution, the grouting property of the grouting material with less than 15% is basically the same, and sometimes it is improved (such as blending). When the amount is 5%~10%), the amount of more than 20% will significantly reduce the frost resistance of the silicon powder grout.
In the high-performance grouting material, from the consideration of reducing the early plastic shrinkage and dry shrinkage, the amount of silicon powder is generally controlled within 10% of the total cgm grout of the cementitious material, and the bubble pitch coefficient is reduced. Frost resistance is often improved.
7, silicon powder and alkali-aggregate reaction
The alkali-aggregate reaction is the reaction between the active silica in the aggregate and the alkali in the cement to form a water-absorbing product, which increases in volume, resulting in expansion and cracking of the grout. When silica ash is incorporated into the grout, the silica fume reacts with the alkali in the cement to prevent such excessive expansion. Practices at home and abroad have shown that silica fume is beneficial for inhibiting the alkali-aggregate reaction in the grout. In calculating the total amount of alkali in the grout, the effective alkali amount of the silica fume is calculated as 50% of the total alkali content.
Should you have any interest in our silica fume in grouting, welcome to contact us. With over 8 years experience in this field, our factory pays high attention to quality. Please rest assured to buy. Low price, fast delivery and excellent service are offered.