Preliminary study of the application of thermal mortar in 3D printed concrete walls

Abstract

3D printing (3DP), as an emerging technology in the construction industry, has the potential to solve the sector’s labour shortages and low efficiency, as well as helping to reduce its negative environmental impact. On the investigative path towards new construction solutions, the thermal performance of buildings must not be compromised. In additively manufactured buildings to date, walls have been printed with cavities that are subsequently manually filled or projected with conventional thermal insulation materials, such as polyurethane and vermiculite. To bridge the gap between conventional building construction and 3DP, it is important to present feasible and effective thermal solutions that can be applied using an automatic mode. This paper explores the viability of applying a commercial thermal mortar as an insulation in 3D printed concrete walls. Therefore, a preliminary experimental campaign was carried out to assess the behaviour of the thermal mortar during and after its application. It was found that concrete walls constrain the drying process of the thermal mortar, generating stresses that lead to the occurrence of cracks. To avoid their formation, some strategies were tested, namely by adding superplasticizer to the mixture, opening joints, drilling holes or opting for an incomplete filling of the cavities.