Experimental and analytical investigation of bond behavior in glass fiber-reinforced composites based on gypsum and cement matrices

In this paper, an innovative composite, formed by a glass fiber net embedded in a gypsum-based matrix and aimed at strengthening masonry structures, is proposed. Experimental and analytical investigations on composite systems with gypsum- and cement-based matrixes, both coupled with a glass fiber net, are illustrated. Bond tests between brick and composite systems were carried out on different bond lengths. The gypsum-based composite (FRGM) showed higher peak loads and a more brittle behavior compared to the response of the standard FRCM system. In the framework of mode-II fracture mechanics, analytical modeling of the tested behavior was undertaken based on local cohesive laws derived from experimental evidence. Both short- and long-bond lengths were modeled, and the results well agree with the experimental behavior of the cement-based system.