Effect of the end conditions on the response of glass textile reinforced cementitious composites under uniaxial tension

Abstract

Textile Reinforced Concrete is a cementitious composite with non-metallic distributed reinforcement, which could exhibit strain-hardening response under uniaxial tensile loading. The tensile behaviour must be characterized properly in order to obtain reliable and appropriate input for structural design. However, it is seen that the end conditions of the test specimen could affect the response, which is discussed in this paper by considering two extreme types of boundary conditions, with the end rotation during testing either being negated or permitted. The strains and displacements were monitored using Digital Image Correlation, along with axial extensometers. The data indicate that fixed ends result in unsymmetric cracking and non-uniform strain distribution across the lateral section of the test specimen whereas rotating ends lead to more uniform cracking and strain distributions. It was further found that the mean width of the strain localization zone is larger for rotating ends. On the other hand, ultimate stress and strain, as well as the average crack opening are comparable for both the end conditions, The maximum crack widths were in the order of 0.2 mm for about 0.8% nominal strain (i.e., close to failure), for the specimens considered. The analysis suggests that rotating end conditions be used to obtain more unambiguous response.