Study on interfacial microstructure of superfine powders reinforced cement based composites at early age

This paper describes interfacial microstructures of hydrated products of cement and three types of superfine powders, which are fly ash, silica fume and nano-SiO₂. Hydration mechanics of these three superfine powders and cement and the improvement of interfacial microstructures are researched also; therefore a concept of secondary interface is developed. The authors believe that these three superfine powders can improve interfacial microstructures and their effect degrees are increased in the order of fly ash, silica fume and nano-SiO₂. From the analysis of the interfacial microstructures of hydrated products, the hydrated product of nano-SiO₂ is the densest and homogeneous when these three powders are used alone, and on the other hand, the hydration degree of the mixture of these three powders shows much higher.