Maximizing fiber content in 3D-printed earth materials: Printability, mechanical, thermal and environmental assessments

Abstract

Earth building materials are experiencing a new renaissance with novel avenues in advanced manufacturing methods such as 3D printing. However, current mix designs are still limited to little to no fiber reinforcement, which can improve ductility and thermal resistivity of the fabricated building assemblies. This research develops 3D printable earth-fiber composites while maximizing natural fiber content for low-carbon and high-performance materials in additive manufacturing. A range of mix designs are formulated and characterized for their printability, mechanical, thermal, and environmental carbon storage performance. The results of this work present successfully developed novel earthen mixtures with natural fiber content ranging from commonplace “cob” (2%wt fiber) to newly developed “light fiber clay” (up to13%wt fiber content and 49% by total volume), incorporating a range of agrowastes products, including wheat straw, hemp, banana, and kenaf fibers. The performance assessment results showcase meaningful improvement of the fiber-reinforced mix designs as opposed to the earthen counterparts, with up to 125% higher compressive strength and up to 86% lower thermal conductivity. The significance of this work lies in the advancement of sustainable and circular materials and assemblies for future manufacturing of socially equitable built environments.