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

Abstract

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 technologyof additive manufacturing, geometrical freedom can instead be utilised to integrate functionalrequirements into mono-material building components. In this research, the additive manufacturingmethod of lightweight concrete extrusion and its potential for thermal performance via geometriccustomisation is explored. It investigates whether the insulating performance of wall components canbe increased through the creation of closed cellular structures, and further, whether these performancefeatures can be functionally graded by locally adapting the geometric properties. A design tool for closedcell wall geometries is created, which integrates lightweight concrete extrusion related fabricationconstraints and takes into account thermal and structural performance considerations. Through thesimulation 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 structuralcapacity during printing is validated. Finally, experimental manufacturing of 1:1 scale architecturalprototypes is executed to test the feasibility of the concept.