Experimental study of the effect of simultaneous mechanical and high-temperature loadings on the behaviour of textile-reinforced concrete (TRC)

Textile-reinforced mortar (or textile-reinforced concrete, TRC) may be used to repair and/or strengthen structural elements of existing construction works (buildings, bridges, etc.) or may be used as constituent elements of new structures. When structures are subjected to fire, they are simultaneously submitted to high temperatures (potentially up to 1200 °C) and mechanical loadings. The elevated temperature thermomechanical behaviour of TRC remains both poorly understood and poorly studied. This study describes the experimental identification, at the macroscale level, of the thermomechanical behaviour of two TRC composites. It shows that the thermomechanical behaviour of two TRC composites is nonlinear and progressively evolves with the increase of the temperature level. The evolution of certain characteristics (the ultimate stress, the stress corresponding to the loss of linearity of the first zone of the stress/strain curve, the stress corresponding to the start of the post cracking stage, the maximum thermomechanical strain, the initial stiffness, the stiffness of the post cracked composite) of the studied materials as a function of the temperature levels will be identified. When temperature levels vary from 100 °C to 300 °C, the main parameters (the ultimate stress, the stress corresponding to the loss of linearity of the first zone of the stress/strain curve, the stress corresponding to the start of the post cracking stage, the initial stiffness, the stiffness of the post cracked composite) of the studied materials are in general gradually decreased with the increase of the temperature level. The influence of a grid and chopped strand textile reinforcement on the cement based composite under thermomechanical loading is analysed and discussed. The experiments show a clear difference between the thermomechanical responses of two TRC composites. Additionally, the cracked specimens are examined.