A research team from the University of Virginia (UVA) has developed an innovative and sustainable new approach to construction that uses the power of 3D printing to create structures made of soil implanted with seeds.

The team consists of Ji Ma, Assistant Professor of Materials Science and Engineering at AVU’s School of Engineering and Applied Science; David Carr, research professor in the university’s Department of Environmental Sciences; Ehsan Baharlou, assistant professor at UVA School of Architecture; and recent UVA graduate Spencer Barnes, who earned his Bachelor of Science in Aerospace Engineering. Given the environmental benefits of integrating green spaces into buildings, the researchers wanted to investigate the possibility of developing complex structures in natural materials. themselves.

Their approach combines the speed, cost-effectiveness and low energy requirements of 3D printing with locally sourced, bio-based materials. This method breaks away from the typical linear approach to design and construction, where raw materials are discarded as end-of-life waste, for a circular approach, in which building materials can be recycled, reducing carbon emissions.

“We switched to earth-based ‘inks’ to gain additional benefits from circular additive manufacturing,” Baharlou told UVA today. “We work with local soils and plants mixed with water; the only electricity we need is to move the material and run a pump while printing. If we don’t need a part printed, or it’s not of the right quality, we can recycle and reuse the material in the next batch of inks.

Barnes was commissioned to conduct experiments with earth-based inks. He used a desktop-sized 3D printer to explore two approaches: printing soil and seeds in sequential layers and mixing seeds and soil before printing. Both approaches worked, and he produced a cylindrical prototype that looked like a Chia Pet. Baharlou then proposed to 3D print more complex structures, such as domes.

UVA Architecture graduate Leah Kirssin and MLA graduate Lizzie Needham, who participated in the project, tested how the material exits the print head without any additives to the soil mix. They found that 3D-printed soil structures can support plant growth, but are limited to plants that can survive with little water. They believe the reason behind this is due to the compactness of the soil when 3D printed, which makes the environment around the plant drier.

To identify possible plant options, Ma researched Carr, who works as director of Blandy Experimental Farm, an environmental science research station in Virginia’s Clarke County. He suggested plants that are found naturally in harsh environments, especially stonecrop, a succulent that thrives in dry, sunny locations and is commonly used in green roofs.

The results of the study, “3D printing of Ecologically Active Soil Structures”, have been published in the journal Additive manufacturing earlier this year.