Stress–strain relationship of steel-fibre reinforced reactive powder concrete at elevated temperatures

This paper presents the stress–strain curves of reactive powder concrete (RPC) specimens in compression tested at increasing temperatures to study the fire resistance of RPC. Stress–strain tests were conducted at various temperatures (20, 200, 400, 600 and 800 °C), and the decomposition phases and microstructure changes were identified using X-ray diffraction and a scanning electron microscope (SEM). The results indicate that RPC with steel fibres exhibits ductility at temperature beyond 400 °C. The compressive strength and elastic modulus of RPC with steel fibres decrease with temperature, whereas the peak strain increases. The energy absorption capacity increases at increasing temperature below 400 °C, but decreases above 400 °C. The steel fibre content does not affect compressive strength and elastic modulus. The SEM images show distinct structural changes corresponding to the deterioration of RPC at elevated temperatures. Property predictive models defined in this paper can be used as input data for computer programs to evaluate the structural fire response at elevated temperatures.

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