CAREER: Fungal Mycelial Improvement and Mud Dauber-Inspired 3D Printing for Sustainable and Durable Earthen Buildings

This Faculty Early Career Development (CAREER) award will support research to develop fungal mycelial improvement and mud dauber-inspired 3D soil printing to strengthen, waterproof, compact, and additively print soil for sustainable, durable, and cost-effective earthen buildings. One-quarter of the global population resides in earthen buildings constructed using unsaturated soil.

Earthen buildings are affordable, recyclable, fire-resistant, and have low carbon footprints due to the inexpensive, locally sourced, and environmentally sustainable nature of soil compared to fired brick, steel, and concrete. However, enhancing the resiliency and durability of earthen buildings often requires soil stabilization using energy-intensive binders (e.g., Portland cement) and labor-intensive compaction.

These methods increase carbon footprints, consume energy-intensive resources, and result in waste-intensive, high-cost, and prolonged construction processes, which conflict with the eco-friendly and cost-effective credentials of earthen buildings. This CAREER project aims to address these challenges by developing innovative fungal mycelial soil improvement and mud dauber-inspired 3D soil printing techniques.

These advancements have the potential to (1) address the affordable housing challenge posed by the significant increase in world population and (2) contribute to a sustainable building industry using eco-friendly materials and reducing greenhouse gas emissions. The integrated education and outreach program aims to (1) increase interest and retention among African American and female students in engineering and (2) raise public awareness about the benefits of earthen buildings and bio-mediated and bio-inspired geotechnics in addressing global challenges linked to climate change mitigation and decarbonization of the building industry.

The research team will engage local parish residents, undergraduate and graduate students, and underrepresented middle and high school students in education and research through activities such as a citizen science project, a 3D soil printing lab module, a capstone design course, outreach demonstrations, and summer research opportunities.

Fungal mycelium can improve the shear strength, erosion resistance, and durability of earthen building walls by binding soil grains, increasing capillary cohesion, and waterproofing soil surfaces. Unlike energy-intensive binders, fungal mycelium is self-grown rather than manufactured. Many fungal mycelia are non-pathogenic and self-healable in soil, ensuring their use in earthen walls is practical and durable.

Mud dauber nest construction can inspire improvements in extrusion-based 3D soil printing by controlling soil type and moisture content, incorporating vibratory compaction, harnessing drying to improve soil shear strength, and printing tubular cellular elements to optimize soil use and improve structural stability. The research objectives include: (1) investigating the hydro-mechanical behavior of fungal-treated soil under wetting-drying processes, (2) developing mud dauber-inspired 3D-printing processes, (3) producing mud dauber-inspired 3D printed cellular wall elements enhanced by fungal mycelium, and (4) assessing the durability of earthen walls assembled with the cellular wall elements.

These innovative techniques are anticipated to eliminate the need for energy-intensive binders and labor-intensive compaction, expedite earthen construction, minimize material waste, and ultimately lead to green, durable, and cost-effective earthen buildings.

This project is jointly funded by the Engineering for Civil Infrastructure program and the Established Program to Stimulate Competitive Research (EPSCoR).

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.