Thermo-hygrometric behavior of hempcrete walls for sustainable building construction in the Mediterranean area

Abstract

Abstract Recent studies have demonstrated that the use of natural materials represents one of the pathways to achieve energy efficiency and environmental sustainability in buildings. In the framework of Circular Economy policies aimed at reducing the consumption of raw materials, shives, as an agricultural by-product of hemp cultivation, have gained a renovated life in the construction sector. Among all the building products made of hemp, hempcrete blocks are the most innovative, because they represent the solution to the needs of new and traditional buildings, offering a high energy saving, combined with the sustainability of materials and products, while remaining, in terms of shape and size, very close to the culture and the construction systems best known by professionals. In order to assess the potential benefits of hempcrete in the construction sector, its environmental performances were evaluated using the LCA methodology, following the international standard ISO 14044:2006+A1:2018 and in compliance with the European standard EN 15804:2012+A1:2013. To this purpose, four non-loadbearing walls were compared in the “cradle-to-gate” scenario, one made with hempcrete blocks and the others with more “traditional” materials. This research aims to be a basis for the development of future guidelines at national and international level in order to guarantee the maximum diffusion of this type of product also in the Mediterranean area. For this reason, it is important to identify the performance characteristics essential for hempcrete products studying their behavior not only as defined in the UNI EN ISO 12571, 2013 standard, but also in the Mediterranean climate. To achieve these objectives, some tests have been carried out to verify the thermo-hygrometric behavior. A 1 m2 of hempcrete wall was submitted to tests in a climatic chamber which simulated the environmental conditions typical of the south of Italy, in terms of temperature and moisture, in order to evaluate thermo-hygrometric behavior of hempcrete. Sensors and thermo-flowmeters for parameter analysis were applied on the wall. On the same material was carried out hygroscopic sorption tests as defined in the UNI_EN_ISO12571,2013 standard. The behavior detected by the experimental measurements on the masonry was compared with the simulated numerical behavior using WUFI software.