EarthWorks: Zero waste 3D printed earthen formwork for shape-optimized, reinforced concrete construction

Abstract

Rapid global urbanization is driving governments and builders to seek paradigm-shifting technologies to speed the construction of housing and infrastructure at a low economic and carbon cost. Here, we present a novel method for fabricating materially efficient, shape-optimized, code-compliant, reinforced concrete structures cast in directly recyclable 3D printed earth formwork, hereby referred to as EarthWorks. This research demonstrates the potential of zero waste, circular formwork that can be manufactured with construction waste soils directly on site. Methods are described for formwork design and toolpathing that accounts for hydrostatic pressure, conventional reinforcement, high accuracy connections, and the fabrication of complex, 3D-shaped geometry with continuous extrusion. In addition, the building design and performance potential of the EarthWorks method are assessed and compared to existing additive formwork technologies from a carbon perspective. Case studies are fabricated demonstrating cast-in-place, tilt-up, and on-site prefab methods to produce bespoke columns, beams, and frames designed to California building code.