Structural Performance and Durability Issues of Vernacular Schist Masonry

Stone masonry is recognized as one of the most used vernacular construction techniques around the world. Although centuries of proven resilience and high adaptability to context, stone masonry has been progressively replaced in construction industry in the last decades, namely in countries as Portugal, by industrial and concrete-based materials and building systems. Nowadays, with the lack of traditional masons, an important part of traditional stone masonry constructive know-how is endangered. In face of growing concerns regarding heritage preservation, researchers are aware of the need to scientifically know such structures. Being less studied, vernacular schist rubble masonry was selected as case study and tested to characterize its mechanical behaviour and durability parameters. The potential of retrofitting of such structures was also assessed [1]. Eighteen double-leave wallets were built following local building traditions [2] and prepared according to 3 different setups of 6 specimens each: i) non-coated; ii) coated with commercial lime coating; iii) coated with commercial lime coating and injected with lime-based grout. The experimental campaign was designed and implemented in stages for a period of three years: i) experimental characterization of stones and mortars; ii) axial compression testing of reference specimens; iii) salt-based accelerated aging following wet-dry procedures [3]; iv) axial compression testing. Damage progression was monitored by visual inspection, mass variation and sonic testing [4].