Innovative and Sustainable Composite Material for the Seismic and Energetic Retrofit of Masonry Infill Walls

The damage caused by recent seismic events has directed the research to develop increasingly innovative materials for the strengthening and repair of existing buildings with problems of obsolescence and vulnerability. In addition to structural problems, in most cases there is also the presence of significant thermal bridges resulting from the lack of adequate insulation. Conventionally, energy and structural improvement interventions for residential buildings are addressed separately using different methods and protocols. This paper proposes a retrofit solution integrated with a new composite material to reduce the seismic vulnerability of existing reinforced concrete buildings, respecting the principles of compatibility, sustainability and reversibility. This study focused on the selection of natural and sustainable materials suitable to improve the mechanical and thermal proprieties of the secondary elements as the masonry infill walls. The mixture consists of natural hydraulic lime and cork in granules, with various weight proportions ensuring desired mechanical and thermal properties. The mortar with the most favorable mechanical and thermal properties was reinforced subsequently with a basalt fiber net. Results show how the new composite material guarantees excellent ductility and can be considered a promising alternative to traditional cement plaster systems.