Effect of using multiple fabric plies on the tensile behaviour of carbon textile reinforced mortar

Abstract

Recently, textile reinforced mortar (TRM) has emerged as a viable strengthening material for reinforced concrete (RC) and masonry structures. Understanding the TRM tensile behaviour is important to achieve an accurate design for TRM strengthening systems. This paper investigates the tensile properties of carbon-TRM composite with multiple fabric plies. Twenty TRM specimens (410 x 50 mm), which varied in the number of fabric plies (one/two/three/four), were prepared and tested in accordance with AC 434 provisions (clevis-grip mechanism). The results revealed a significance of the number of fabric plies on the tensile capacity as well as the failure behaviour of the TRM composite. The failure mode had changed from ductile fabric slippage (associated with up to 3 fabric plies) to brittle fabric delamination in carbon-TRM specimens when using 4 layers of fabric. As expected, the TRM tensile capacity had proportionally increased with the number of fabric plies. The effect of the number of fabric plies was less significant (within 20%), though, on the ultimate tensile stresses of the impregnated fabric. The results verified the established bilinear trend for TRM tensile stress-strain relationship that indicates two sequential phases, namely, noncracked/stiff and cracked-section phases. However, the TRM cracked tensile modulus had somewhat increased with an increase in the number of fabric plies.