Compressive and tensile properties of reactive powder concrete with steel fibres at elevated temperatures

This paper presents the effect of temperature on the compressive and tensile properties of reactive powder concrete (RPC). The influence of temperature, steel fibre content, hold time, dimension of specimens and explosive spalling in the temperature range of 20–800 °C are examined. The experimental results indicate that 2% steel fibres (volume content) can prevent explosive spalling of RPC and significantly enhance the compressive and tensile strengths. Cube compressive strength decreases at 100 °C, increases at temperatures from 200 to 500 °C, and decreases at temperatures above 600 °C. Below 300 °C, the cube compressive strength of RPC increases as the fibre content increases, but decreases above 300 °C as the fibre content increases. The tensile strength of RPC with steel fibres decreases at temperatures below 200 °C, increases at temperatures ranging from 200 to 300 °C, and decreases at temperatures above 300 °C. Distinct changes in the microstructure of RPC reveal mechanical properties from a macroperspective. Data generated from tests are utilised to develop relations for expressing the mechanical properties of RPC as a function of temperature.

► The temperatures, fibre content, hold time, dimension and spalling are investigated.
► Explosive spalling occurs in temperature ranging from 260 to 520 °C.
► 2% steel fibres prevent spalling and significantly increase mechanical properties.
► High content of steel fibres has little effect on mechanical properties.
► The tensile strength of RPC suffers more loss than the compressive strength.