Additive Manufacturing of Thermally Enhanced Lightweight Concrete Wall Elements with Closed Cellular Structures

Building envelopes incorporate a multitude of functions, such as structure, room enclosure, insulation, and aesthetic appeal, typically resulting in multi-material layered constructions. With the technology of additive manufacturing, geometrical freedom can instead be utilised to integrate functional requirements into mono-material building components. In this research, the additive manufacturing method of lightweight concrete extrusion and its potential for thermal performance via geometric customisation is explored. It investigates whether the insulating performance of wall components can be increased through the creation of closed cellular structures, and further, whether these performance features can be functionally graded by locally adapting the geometric properties. A design tool for closed-cell wall geometries is created, which integrates lightweight concrete extrusion related fabrication constraints and takes into account thermal and structural performance considerations. Through the simulation of heat transfer, generated wall geometries are analysed for their thermal performance. By calculating the layer cycle times and determining the overhang during extrusion, the structural capacity during printing is validated. Finally, experimental manufacturing of 1:1 scale architectural prototypes is executed to test the feasibility of the concept.