The Green Wall: The Project of a Sustainable 3D-Printed Bearing Wall with Integrated Vegetation

Global warming and climate change have become critical challenges of our time, prompting international initiatives such as the European Green Deal and the New European Bauhaus to promote sustainable architectural solutions together with the implementation of digitalization to increase the efficiency of the construction process. In this context, the use of vegetation to improve the thermal insulation of buildings and biodiversity while contributing to carbon sequestration has become a popular strategy to increase sustainability. This paper aims at presenting a model of a bearing wall made of 3D printed stone ashlars with integrated greenery. Blocks are conceived to have interlocking joints, similar to the LEGO system, and have a tridimensional configuration that creates a pattern on the wall surface that recalls rusticated stone. This pattern works as a decoration and its overhangs are sufficient to obtain cavities to host vegetation. This constructive system has been designed to merge a series of characteristics such as: • a simple and fast assembly process, that makes it suitable also for emergency contexts; • a good thermal performance due to the presence of vegetation on the outer surface; • the possibility to customise the properties of the ashlars thanks to the use of 3D-printing. Blocks can have different dimensions, different overhangs or can be customised to optimise their static behaviour, their thermal performance and their weight by changing their internal porosity; • the possibility to use recycled materials like waste stone powder or debris from demolition, keeping the entire construction process greener. After an illustration of the designed constructive system, some possible architectural applications will be shown. In the end, the fabrication process of a prototype will be described. The prototype consists of a portion of the designed wall, realized through binder jetting concrete 3D-printing. This model has been realised for the international exhibition Marmomac Meets Academies 2024, curated by prof. Giuseppe Fallacara and held in Verona in September 2024, in the occasion of the international fair Marmomac.