PROBABILISTIC DAMAGE EVOLUTION IN MASONRY STRENGTHENED WITH FRCM SUBJECTED TO AGGRESSIVE ENVIRONMENT

This paper concerns applications of advanced Fiber Reinforced Cementitious Matrix (FRCM) systems on existing masonry structures. At the state of the art, it turns out that the FRCM-to-masonry bond is affected significantly by substrate properties and environmental conditions. To this purpose, an experimental campaign was realized recreating different experimental scenarios, and the results thus achieved were critically and comparatively discussed. In particular, specimens constituted of two types of fired-clay bricks (either with a single brick or a running bond masonry) were reinforced with a carbon mesh, externally glued by means of a cementitious or a lime-based matrix, and then exposed to salt crystallisation induced by capillarity along months. Visual observation combined with laser profilometer measurements revealed progressive deterioration of the surface in terms of loss of material and even bulging activated at the composite-to-masonry interface. Pull-off tests on deteriorated samples confirmed progressive weakening of the bond in terms of nominal strength at peak. To interpret the amount of data, a novel probabilistic model was proposed, apt to predict possible damaging effects over the surface of reinforced masonry elements.