Sandy Curth

Biocementation is an ongoing Programmable MUD research program focused on the development of bio-engineered local materials for low-carbon construction.

How do we design with microbes?

Can we make high-performance building materials with nothing more than the ground beneath our feet?

Collaborators: Laura Gonzalez

Supported by: The Programmable Mud Initiative, Huang Hobbs Biomaker Space, MIT Biological Engineering, MIT Architecture

Additive manufacturing with earth is an emerging, though largely uncharacterized, approach to fabricating low embodied carbon structures. It is critical to establish methods for processing 3D printed, locally sourced earthen materials in different environments to validate large-scale earthen additive manufacturing as a tool to address a growing global need for housing and climate-resilient architecture. We present a set of reproducible design guidelines for sourcing, processing, and characterizing locally sourced earthen materials. Soil type, moisture and fiber content, particle size distribution, and unconfined compressive strength are determined. Additionally, novel bridging, cantilevering, and hydrostatic pressure (formwork) testing methods are developed to link design constraints for full-scale printed structures to material characteristics. Modular and conformally printed full-scale wall prototypes are printed with a 6-axis robotic system. A Life Cycle Assessment of the prototypical earth printing system is conducted, establishing a point of comparison to the climate impact of other construction systems, including rammed earth, concrete masonry units, and 3D printed mortar. We demonstrate that printing highly functional building elements with repeatable mechanical characteristics is possible using locally sourced earth mixtures. By illustrating a range of reproducible material and geometric possibilities, we expand the design space of additive earth and its applications.

Rapid global urbanization is driving governments and builders to seek paradigm-shifting technologies to speed the construction of housing and infrastructure at a low economic and carbon cost. Here, we present a novel method for fabricating materially efficient, shape-optimized, code-compliant, reinforced concrete structures cast in directly recyclable 3D printed earth formwork, hereby referred to as EarthWorks. This research demonstrates the potential of zero waste, circular formwork that can be manufactured with construction waste soils directly on site. Methods are described for formwork design and toolpathing that accounts for hydrostatic pressure, conventional reinforcement, high accuracy connections, and the fabrication of complex, 3D-shaped geometry with continuous extrusion. In addition, the building design and performance potential of the EarthWorks method are assessed and compared to existing additive formwork technologies from a carbon perspective. Case studies are fabricated demonstrating cast-in-place, tilt-up, and on-site prefab methods to produce bespoke columns, beams, and frames designed to California building code.

Additive manufacturing with earth is an emerging, though largely uncharacterized, approach to fabricating low embodied carbon structures. It is critical to establish methods for processing 3D printed, locally sourced earthen materials in different environments to validate large-scale earthen additive manufacturing as a tool to address a growing global need for housing and climate-resilient architecture. We present a set of reproducible design guidelines for sourcing, processing, and characterizing locally sourced earthen materials. Soil type, moisture and fiber content, particle size distribution, and unconfined compressive strength are determined. Additionally, novel bridging, cantilevering, and hydrostatic pressure (formwork) testing methods are developed to link design constraints for full-scale printed structures to material characteristics. Modular and conformally printed full-scale wall prototypes are printed with a 6-axis robotic system. A Life Cycle Assessment of the prototypical earth printing system is conducted, establishing a point of comparison to the climate impact of other construction systems, including rammed earth, concrete masonry units, and 3D printed mortar. We demonstrate that printing highly functional building elements with repeatable mechanical characteristics is possible using locally sourced earth mixtures. By illustrating a range of reproducible material and geometric possibilities, we expand the design space of additive earth and its applications.