Hempwerks : non-corroding concrete reinforcing made with natural fiber and thermoplastics

Abstract

Infrastructure has been deteriorating for decades and climate change and urbanization are acceleratingtheir degradation. Much of our infrastructure is built with reinforced concrete, whose steel reinforcement can become a liability if allowed to corrode. This thesis explores the development of a non-corroding reinforcing alternative made from natural fibers and thermoplastic. The impact of natural fiber composite (NFC) reinforced concrete has been investigated at multiple scales of performance: structural, processing, and environmental. Structural and environmental performance has been calculated based upon material database values, while processing performance has been observed though the production of multiple NFC samples. The structural performance calculations reveal that flax reinforced composites can match the tensile strength of steel with a fiber volume ratio between 44% and 50% and match the elastic modulus of GFRP with a fiber volume ratio between 46% and 49%. The processing performance experiments reveal the “jacket” commingling method results in better fiber saturation than the “parallel” or “twisted” methods. The environmental performance results reveal that given a constant fiber volume ratio, PLA matrix composites demand only 50%-51% the embodied energy of GFRP, regardless of the selected natural fiber reinforcing.