Large-scale construction in resource-starved and harsh environments like Antarctica, the Moon, and Mars remains conceptual. A major challenge is forming load-bearing materials onsite. This thesis presents the development and optimization of a new class of concrete based on hydrogel binders, maximizing in-situ resource utilization and achieving adequate mechanical performance after curing at subzero temperatures and near-vacuum air pressure. The hydrogel-based concrete (HBC) is formed through a two-step process: mixing flowable hydrosol with inert aggregates and hardening the material via environmentally induced sol-to-gel transition. HBC leverages spontaneous water phase changes and polymer cross-linking, demonstrating notable energy and material efficiencies.

The thesis encompasses fo...[ Read more ]

Large-scale construction in resource-starved and harsh environments like Antarctica, the Moon, and Mars remains conceptual. A major challenge is forming load-bearing materials onsite. This thesis presents the development and optimization of a new class of concrete based on hydrogel binders, maximizing in-situ resource utilization and achieving adequate mechanical performance after curing at subzero temperatures and near-vacuum air pressure. The hydrogel-based concrete (HBC) is formed through a two-step process: mixing flowable hydrosol with inert aggregates and hardening the material via environmentally induced sol-to-gel transition. HBC leverages spontaneous water phase changes and polymer cross-linking, demonstrating notable energy and material efficiencies.

The thesis encompasses four main works. First, the combined effects of mix design and extreme conditioning (low temperature and air pressure) on material properties are experimentally studied, revealing the relationship between gel microstructure particle-to-particle joints and the mix design-curing scheme, establishing the methodology for manufacturing HBC. Second, a new multi-scale modeling framework quantifies the effect of gel microstructure to optimize material design. At the micro level, analytical modeling and direct tests on bonded particle joints explore and validate constitutive relationships. At the macro level, discrete element method (DEM) modeling incorporates calibrated micro-level data to simulate bulk properties of HBC. Third, biosynthetic methods enhance the gel's binding ability; specifically, genetically modified baker’s yeast generates adhesive, environmentally tolerant biopolymers to improve particle-to-particle bonds. Fourth, the feasibility of forming HBC via 3D printing (binder jetting) in situ is studied through experimental and theoretical approaches.

These findings underscore the critical role of microstructure and mechanical modeling in optimizing hydrogel-based concrete for extreme environments. The insights gained enhance our understanding of HBC and inform the development of bio-HBC with improved mechanical properties. By establishing a robust framework for modeling the mechanics of these composites, this work offers valuable guidance for future research and applications.