As an admixture, silica fume has been widely used in the preparation of high-strength concrete. It can reduce the use of cement clinker. Because of the strong activity of silica fume, pozzolanic reactions and micro-aggregate filling effects can occur in the concrete. The incorporation of silica fume in high-strength concrete can improve the strength, impermeability, frost resistance and chemical resistance of concrete, as well as inhibit or reduce the reaction of alkali aggregates. The application prospect is very broad.
Due to the low density of silica fume, which is about one tenth of the density of cement, it has a great disadvantage in storage and transportation. As a result, silica fume manufacturers use densified technology to increase the bulk density of the original silica fume and become densified microsilica.
The role of the densified silica fume in the pulp and concrete (porosity characteristics, microscopic morphology, etc.):
1. The incorporation of densified silica fume will reduce the compressive strength of the pulp, but it will increase the compressive strength of the concrete;
2. densified microsilica fume increases the porosity of hardened paste;
3. The clustering phenomenon of the densified silica fume in the paste hardened paste is very obvious, but it is difficult to find the cluster phenomenon in the concrete.