Experimental behavior of glass-FRCM Composites Applied onto Masonry and Concrete Substrates

The use of Fiber Reinforced Polymer (FRP) composites has become a popular solution for retrofitting and strengthening of existing concrete and masonry structures. However, some drawbacks of this technique, mainly associated with the use of organic resins, have been reported. To overcome such drawbacks, the development of composite materials in which the organic resins are replaced with inorganic matrices has recently caught the attention of the civil engineering industry. Among these newly developed systems, Fiber Reinforced Cementitious Matrix (FRCM) composites, which are comprised of high strength fibers embedded within an inorganic matrix, have shown promising results. However, research on this topic is still limited and important aspects, such as the bond behavior between the composite and the substrate, are not fully understood and require further study. This paper presents the results of an experimental campaign aimed at investigating the influence of the type of matrix and substrate on the bond behavior of FRCM composites. Glass-FRCM composite strips were applied onto concrete and masonry substrates and then tested by means of a classical push-pull single-lap direct-shear test set-up. A cementitious and a lime-based matrix were employed to apply the same type of fiber on concrete and masonry substrates, respectively. FRCM-concrete and FRCM-masonry joints reported the same failure mode. However, higher values of the peak load were obtained for the lime-based glass-FRCM composite applied onto masonry substrates than with the cementitious glass-FRCM composite applied onto concrete substrates.