Description
This paper presents experimental and analytical investigations about the bond behaviour between different types of FRCM systems (basalt, steel and Polypara-phenylene-benzo-bisthiazole (PBO) FRCM) and masonry substrates. Single lap direct shear tests (DS) were performed on single layer FRCM-clay brick masonry joints after a preheating process at temperatures ranging from 100 ºC to 500 ºC (measured at the interface FRCM/substrate). As expected, the variation with temperature of the bond properties (strength, stiffness and slip at the peak stress) is strongly dependent on the type of strengthening system considered. The results obtained showed that the FRCM systems comprising basalt and PBO fibres presented a greater sensitivity to temperature than those reinforced with steel. For instance, after being exposed to 500 ºC, the specimens strengthened with PBO and Basalt-FRCM presented significant bond strength reductions (more than 50% of ambient temperature values), whereas those reinforced with steel-FRCM exhibited bond strength retentions of ~ 70%. Finally, the suitability of empirical models to predict the variation with temperature of the FRCM bond properties was assessed. The results obtained, evidenced that the predictions of the empirical models are relatively in good agreement with the test results, proving their suitability for design purposes.