Repair and strengthening of hollow concrete block masonry walls using textile-reinforced mortar (TRM)

Abstract

The use of a Textile-Reinforced Mortar (TRM) system, as a retrofitting technique, for Maltese unreinforced hollow concrete block (HCB) walls, has been experimentally investigated. Nine half scale masonry HCB wall panels were subjected to racking load tests to determine their response to in-plane loading. This study investigated and compared the behaviour of unreinforced wall samples, with wall samples reinforced using a basalt textile, and two types of mortar matrices. One mortar matrix was commercially available, and the other composed of a sand-cement mixture. Application of TRM to one face of wall samples was compared to application to both faces of wall samples. The omission of mesh reinforcement from TRM strengthening was also considered. Furthermore, the effectiveness of TRM as a repair technique was investigated by testing pre-damaged wall samples. The structural response of each wall sample was assessed by analyzing crack formation and propagation, patterns of displacement with time, and load attainment. Results indicate that TRM is very effective at enhancing in-plane load resistance, especially when applied to both wall surfaces, both for walls as-built-strengthened, and for walls pre-damaged-repaired. ln these cases, failure was almost always dictated by transverse block splitting. Although to a lesser extent, one sided strengthening also resulted in substantial strength gain, whilst failure was more ductile. Despite still registering a large strength enhancement, the application of a mortar matrix and omission of mesh reinforcement led to a very brittle failure mode.