Experimental characterisation of hygrothermal properties of a 3D printed cementitious mortar

3D printing (3DP) presents great potential for automation, sustainability, and quality control in the construction sector. However, research on 3DP in Construction has been carried out primarily from a structural standpoint, and information on the thermal performance, comfort and energy efficiency of these solutions remains very limited. Given the importance of assessing how printed walls perform when subjected to hygrothermal solicitations, this work experimentally analyses a cement-based mortar specially developed for 3DP. An extensive laboratory campaign was carried out and the following set of physical, hygric and thermal properties were obtained: the dry bulk density, saturation moisture content, specific heat capacity, porosity, water absorption due to capillary action, water vapour permeability, thermal conductivity (dry and moisture-dependent), and the sorption isotherm. The results show that the 3D printed cement-based mortar, which presents a dry density of 2060 kg/m3 and a thermal conductivity of 1.33 W/(m∙K), has a hygrothermal performance comparable to that of traditional cast concrete. This indicates that additional thermal insulation materials are required to obtain appropriate thermal performance through the building envelope. Moreover, this detailed hygrothermal characterisation is suitable for design purposes, allowing the use of the obtained properties in future numerical simulations, important for studying the hygrothermal performance of printed building elements in service.