FMRG: Eco: Process-Structure-Property Relationships of 3D Printed Earth Materials and Structures

This Future Manufacturing Research Grant (FMRG) EcoManufacturing project will comprehensively characterize optimal mix designs for 3D printed earth materials and structures, linking microstructural development and soil science with material and structural property characterization and optimization of 3D printing methods. Earth materials are an emerging, sustainable alternative to cementitious materials because of their low embodied carbon, affordability, safety, and thermal characteristics. By using minimally processed materials and sourcing raw materials from the construction site, 3D-printed earth structures could substantially reduce transportation, chemical treatments, excess manufacturing, warehouse storage, and intermediary storages that are inextricably intertwined with cementitious materials. Using a range of bacterial and biopolymer binding agents, as well as bio-based fibers and nano-fibers reinforcing additives, this project will characterize printable mixtures of earth- and bio-based building materials—modernized versions of ancient technologies—as a critical step for climate-friendly digital manufacturing of the built environment. In addition to creating new scientific knowledge for additive manufacturing using nonconventional materials, this project supports education and diversity by developing a graduate earth-based technology course and an extracurricular experience for students from marginalized communities that includes hands-on materials assessment, digital fabrication of an earth-based shelter, and community activities.

Through a comprehensive series of optimized mix design development, fresh- and hardened-state properties characterization will produce an effective and sustainable framework for improved shape stability and interlayer properties of the final printed earth structures. The proposed research links, for the first time, the following multi-scale investigations to advance the science and engineering of 3D printed earth materials and structures: (1) establishing the soil characterization and microstructural design methodologies of 3D printable earth mixtures, (2) elucidating the process-structure relationships of 3D printed earth materials and the effects of additives, including a range of biomineralizing microbes and biopolymers, on fresh-state properties, (3) characterizing the hardened-state properties with a focus on alternatives to stabilization, and (4) advancing the processing science of small- and large-scale 3D printed earthen structures. This research and educational effort will contribute to a broader interdisciplinary scope on quantitative and qualitative expertise related to the automated construction, mechanical, thermal, and environmental impacts of earth materials, a critical future in low-carbon and affordable buildings.

This Future Manufacturing project is jointly funded by the Divisions of Civil, Mechanical and Manufacturing Innovation (CMMI), Engineering Education and Centers (EEC), and Industrial Innovation and Partnerships (IIP) in the Directorate of Engineering, and by the Division of Materials Research (DMR) in the Directorate for Mathematical and Physical Sciences (MPS).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.