What are the application conditions of concrete silica fume must pay attention?

Although the micro-silica fume of concrete can effectively improve the microstructure of hardened cement paste and concrete, due to the small particle size and large specific surface area of the micro-silica fume, the cement paste and concrete mixed with micro-silica fume, with the increase of the amount of micro-silica fume, the water demand increases, the self-shrinkage also increases. Therefore, the dosage of silica fume is generally limited to 5% ~ 10%, and the water demand is adjusted with high-efficiency water reducing agent. At the same time, there is a compatibility problem between cement, silica fume and admixture. Therefore, attention must be paid to its application conditions when using silica fume. Because the concrete mixed with silica fume may lead to the autogenous shrinkage of concrete, and the concrete mixed with silica fume is generally concrete with special requirements, therefore, the use of silica fume in concrete has a beneficial effect on hardened cement paste and concrete performance, while the adverse effects brought by the concrete silica fume must be minimized, the most effective way to solve this problem is to add microsilica while adding other pozzolanic materials or other substances, so that they can learn from each other to achieve better technical and economic results.