Environmental durability of FRCM strengthening systems and comparison with dry fabrics

Fiber Reinforced Cementitious Matrix (FRCM) composites have been recently introduced for repairing and strengthening masonry structures. Even if they proved to be an effective solution for structural applications, their durability is still an open issue, which is fundamental to guarantee the long-term effectiveness of the strengthening intervention. In fact, FRCMs may be subjected to a combination of different environmental conditions that may affect their performances: humidity, rainfall, freeze/thaw cycles, exposure to saline and alkaline environments are some of the conditions that may promote deterioration over time. In order to investigate FRCMs durability, an extensive experimental campaign has been carried out on different FRCM systems (basalt, glass and steel fibers) through tensile tests on conditioned and unconditioned samples. Tests have been performed both on FRCM coupons and on dry fabrics, with the aim of analyzing the effect of the matrix in terms of mechanical behavior and external protection of the fabric under aggressive environments. The creation of an experimental database on the effects of environmental conditions is a first step to analyze long-term properties of these composite materials and to suggest appropriate strength reduction factors to be taken into account for the design of durable retrofitting interventions.