Tensile characterization of multi-ply fabric-reinforced cementitious matrix strengthening systems

Abstract

Fabric reinforced cementitious matrix (FRCM) is a composite consisted of high-strength fibers impregnated in a cement-based mortar, and is commonly used for strengthening reinforced concrete and masonry structures. Comprehending the tensile behavior of FRCM is important to achieve a reliable and accurate design of FRCM strengthening systems. The current paper reports on the results of an experimental study on the tensile characterization of FRCM. A total of 40 FRCM specimens (410 50 mm, varied in thickness) were prepared and tested. The tensile characterization tests were conducted according to AC 434 guidelines using clevis-grip mechanism. The tests were used to assess the effect of two parameters: (a) fabric type (carbon/glass) and (b) number of fabric plies (one/two/three/four). The results showed that the tensile strength of carbon-FRCM specimens was approximately 1.33 times that of the glass-FRCM counterparts. Three distinct failure modes were observed, namely, (a) ductile fabric slippage in carbon-FRCM (up to three plies of fabric); (b) brittle fabric delamination in carbon-FRCM with four plies of fabric; and (c) brittle fabric rupture in glass-FRCM systems. The FRCM tensile load-carrying capacity had proportionally increased with the number of fabric plies; less significant effect (within 20%) was observed on the corresponding ultimate tensile stresses (considering the net fabric area as the effective area).