Sustainable adobe bricks with seagrass fibres. Mechanical and thermal properties characterization

There is an incipient necessity and interest of generating sustainable materials for application in green buildings. In this study, the capability of Posidonia Oceanica seagrass, a biomass by-product from the Mediterranean coastlines, is analysed as a reinforcement material in adobe bricks. For this purpose, earthen specimens with these sea-plant fibres were compared with the most traditional additives for this purpose, i.e. straw-based adobes. Both biomass fibres were included with different lengths and quantities. First, to understand their behaviour, the fibres were evaluated; water absorption and tensile strength tests were performed. Test specimens themselves were subjected to mechanical and thermal tests as well as measuring dimensional changes. Tested as fibres, straw presented higher tensile resistance and water absorption than seagrass; but tested within adobe specimens, straw containing samples had worse mechanical behaviour than those containing seagrass. Specially, adobe with Posidonia Ocenaica seagrass fibres with their natural long length showed to be the most suitable in terms of mechanical behaviour. Furthermore, good thermal conductivity results were achieved with this level of biomass reinforcement, generating a sustainable and value-added construction product.This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31). The authors of this paper would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. Dr. Pisello thanks Fondazione Cassa di Risparmio di Perugia for supporting her research on bio-materials and circular economy (Project SOS CITTA’ – 2018.0499.026)