The influence of high temperature exposure on the tensile and cracking behavior of crimped-textile reinforced mortar composites (TRMs)

Abstract

The use of textile reinforced mortar/concrete composites (TRM) in strengthening applications and new constructions necessitates understanding its behavior after exposure to high temperatures. Therefore, in this study, the residual tensile and cracking behavior of carbon based TRMs was studied. A total of 96 TRM samples were tested in the temperature range of 25–450 °C. The main parameters studied were the textile crimp, textile orientation, textile coating, multiple textile layers and hybrid reinforcement. The hybrid TRM was formed with a combination of uncoated and styrene butadiene (SBR) coated textile layers. This study served as one of the first experimental campaigns to use digital image correlation (DIC) for understanding the residual crack opening behavior of TRMs. The results demonstrated that the properties of the TRMs were noticeably influenced by temperature exposure of 450 °C. Unlike the uncoated or hybrid textile TRMs, the SBR coated textile TRMs demonstrated curvature and cracking after 450 °C exposure. The study showed that the load aligned crimped yarn TRMs were always associated with larger deformation irrespective of the exposure temperature. The crack openings also increased significantly after exposure to 450 °C. Whereas the presence of heat formed cracks caused higher initial rate of crack openings. The evolution in the crack spacing with increasing temperature fluctuated due to the possible relative degradation of cracking strength vs interfacial mortar textile bonding. Finally, the proposed empirical equation showed a good fit to the residual average crack opening vs. stress relations.