Research on the influence of the Reactive Powder Concrete Mechanical Properties by Nano-Silica

Reactive powder concrete(RPC) is a new type of cement composite material with high mechanical properties,which is designed according to the maximum density theory.Nano-SiO2 is smaller than the diameter of each component in RPC,it not only can fill the tiny gaps physically but also has high pozzolanic activity.The base mix of RPC is selected through orthogonal design of L9(34)by considering the water-cement ratio,silica fume and slag.Then,by adding different contents of nano-SiO2.It is found that the flexural strength,compressive strength and splitting tensile strength is enhanced when the content of nano-SiO2 is between 0.5% and 1% by analyzing the strength values of 7 d and 28 d.If combined with SEM,you can find that the nano-SiO2 makes the cement matrix respond more fully and improve the interface structure and reduce the structural defects of cement paste which shows the mechanism nano-SiO2 enhance its mechanical properties from the micro.