Durability of CRM reinforcements

The use of inorganic matrix fiber-reinforced systems has been investigated and promoted in the last years for the structural repair and rehabilitation of historical masonry constructions. Fabric Reinforced Cementitious Matrix (FRCM) and Composite Reinforced Mortar (CRM) are the two families of materials that have been studied and put into practice. The high physical-mechanical compatibility with masonry and ease of installation are the key points that made these systems suitable for structural engineering practice. Durability issues related to the presence of an alkaline matrix and aggressive agents in harsh environments are the actual frontier of the research in the field. This experimental study allowed to investigate the mechanical behavior and durability of a Glass Fiber Reinforced Polymer (GFRP) grid and GFRP pultruded bar used respectively as reinforcement and connectors in a new CRM system. Tensile tests were performed before and after aging consisting of separate exposure to moisture, alkaline solutions, freeze-thaw cycles, and marine water. Different exposure times were investigated. Pull-out from different substrates and lap splice tests were also performed on the GFRP connectors. Measurements of the glass transition temperature and electronic microscopy completed the experimental protocol. The results in terms of mechanical comparison between the control and aged specimens are provided and discussed in the paper.