Towards the assessment of the shear behaviour of masonry in on-site conditions: A study on dry and salt/water conditioned brick masonry triplets

In this paper an experimental study conducted on fired-clay brick masonry triplets built with cement- and hydraulic lime-based mortars and subjected to artificial weathering cycles is presented. A cycle is constituted by (1) a wetting phase by capillary rise of either a saline solution or deionized water and (2) a drying phase in oven. The aim of the accelerate weathering cycles is to simulate on-site conditions of masonry structures subjected to rising damp and salts attack due to daily and seasonal microclimatic changes. For comparison purposes, triplets subjected to drying cycles only were also considered. At the end of the weathering process, the triplets were shear tested in order to quantitative assess the separate and combined effect of water and salts within the pores on the mechanical behaviour. Shear parameters were interpreted on the basis of the microstructural characteristics of the constituent materials. Particular attention was given to the pore size distribution, salt amount, and distribution within the specimens after the conditioning procedure, finding significant correlations. Results show that the triplets shear behaviour is influenced by the damp/salts presence to a different extent depending on the materials involved.