Study on behaviour and strength of SFRC under combined action of compression and shear

Steel fibre reinforced concrete (SFRC) has been gaining popularity in load-carrying members because of its positive contribution to both concrete strength and energy absorption capacity. This paper presents both experimental and theoretical study of the fibre reinforcing effect on the concrete failure mechanism. The compression/shear tests of cubic steel fibre reinforced concrete specimens with fibre volume fractions of 0%, 1.5% and 3% are conducted in the wedge shear apparatus. Their failure patterns are analysed at macro-and meso-scale levels. Subsequently, these experimental data are analysed by a twin-shear strength theory. One concise compression/shear failure criterion is then developed for SFRC. It is found that the predicted results by this criterion agree well with those by experiments. Finally, the changes of concrete twin-shear strength parameters with the fibre volume fraction are explored.