Terrestrial in-situ resource utilization of geopolymers as sustainable construction materials

• Conner Nelms, Chemical Engineering, University of Delaware

• Norman Wagner, Chemical and Biomolecular Engineering, University of Delaware

Modern concrete production is a leading contributor to global climate change, responsible for approximately 10% of anthropogenic CO2 emissions and consuming massive volumes of freshwater. Geopolymer cement presents a highly promising, sustainable alternative, offering a zero-emission, net-water-neutral process. Synthesized from aluminosilicates sourced from clay, fly ash, and other sustainable feedstocks, geopolymers are also highly relevant for in-situ resource utilization (ISRU). However, to demonstrate structural viability, the production mechanism must be scaled from standard 1x1cm ASTM testing cubes to full-size bricks. This research focuses on formulation optimization and incremental tests to achieve this scale-up. Specifically, the compressive strength of an in-house geopolymer cement was evaluated utilizing a 1:2:3 volumetric aggregate mixing ratio. Additionally, further formulation optimization was completed to evaluate the efficacy of additive manufacturing techniques . By analyzing testing datasets against ASTM standard guidelines, this work advances the scalable production and 3D printing capabilities of geopolymers, paving the way for their implementation as a primary, eco-friendly construction material.