Experimental Study On The Mechanical Properties And Explosive Spalling Of Reactive Powder Concrete Exposed To High Temperatures

Reactive powder concrete (RPC), developed in the late1990s, is known as an advanced concrete-based composite with ultra-high strength and outstanding performance. In this paper, based on the laboratory testing and theoretical analysis, the mechanical properties and explosive spalling of RPC exposed to temperatures are probed. By compressive and three-point bending testing, the tendency of compressive strength, split tensile strength, flexural tensile strength of RPC200with the increment of volumetric content of steel fibers have been investigated, the contribution of steel fibers to improve the crack-resistant capacityand toughness with various deformation mechanisms have been analyzed. Based on SHPB testing data, the properties of failure model, strength of RPC with varied fiber volumes and impact strain rates are analyzed. The deterioration of compressive strength, elastic modulus of RPC under high temperature are analyzed, and the explosive behaviour and the changing regularity of temperature field with time and space are analyzed by high temperature testing. The thermophysical properties of RPC, such as thermal conductivity, thermal diffusivity, specific heat capacity et al, with different steel fiber volumetric fractions are investigated by means of high temperature tests. Adopted by the mercury injection method, the effect of temperature on pore structure characteristics such as porosity, pore volume of RPC are investigated. The variation of vapour pressure in RPC under temperature is disclosed. This study attempts to provide an important reference to scientific evaluate the mechanical properties, develop a kind of high temperature resistance and high performance concrete, and promote the research and application of RPC.