Place the Waste: Designing with Reclaimed Concrete

Recognising the high rate of structurally sound concrete discarded as demolition waste, this study suggests a novel workflow for designing funicular structures using reclaimed concrete. The workflow is centred around a Voussoir Stacking Algorithm, created using COMPAS, which stacks quadrilateral voussoirs on a funicular thrust surface. Three design principles underpin the algorithm. First, opposing voussoir faces are aligned parallel to the force flow. In contrast, the remaining pair, which represents the load-transferring faces, is aligned perpendicular to it to prevent sliding failure. Second, the thrust surface is confined within the middle third of the voussoir to avoid the formation of hinges and cracks. Third, voussoirs are cut into hexagonal shapes, and staggering is ensured among neighbouring voussoirs to create an interlocking geometry. To validate the algorithm, 12 structures were made using different stocks, deployment strategies, and thrust surfaces. Since trimming the concrete elements is permitted by the algorithm, it was measured that, on average, 47% of the volume per voussoir is retained in the final structure. Finally, suggestions are made to improve the retained volume by expanding the criteria used to select the voussoir of best-fit to include distance-to-staggering, a local radius of curvature, and the surrounding voussoir dimensions.