A transformative development in 3D concrete printing promises innovation in the construction industry—with better and more environmentally friendly structures coming at a lower cost, say researchers at the University of Michigan.

Architect Mania Aghaei Meibodi and researchers Alireza Bayramvand and Yuxin Lin of the DART lab at U-M’s Taubman College of Architecture and Urban Planning, have developed a method for creating ultra-lightweight, waste-free concrete. The method reduces weight by 72% as compared to conventional, solid concrete of the same size, and is leading to new partnerships and patents beyond U-M.

Previous approaches around 3D concrete printing, or 3DCP, aim to digitize construction and reduce concrete consumption. However, the most widely used approach has geometric limitations that restrict its application to simple shapes like orthogonal walls.

“This leads to high concrete consumption and limits its application for lightweight forms that entail intricate shapes like branching and angular tubular forms, overhangs, layer cantilevers, and filament section or angle variations,” said Aghaei Meibodi, assistant professor of architecture at Taubman College.

The most widely used approach on construction sites uses a planer toolpath, parallel to the ground or along a single plane, to guide the 3DCP tool head. The tool head follows this path and extrudes mortar from the printer head, depositing it in horizontal layers.

After each layer is deposited, the extruder nozzle is raised by the height of the deposited layer. This process is repeated to create a concrete mold, which is later filled with rebars and concrete.

The U-M team’s new approach, the “Shell Wall,” demonstrates a computational design and robotic 3D printing technology that effectively combines topology optimization with 3D concrete printing. Topology optimization is a technique that generates the most efficient distribution of material based on performance criteria, such as strength or weight, for a given set of support (The Smart Takes from the Strong).

The team created a computational model that synergizes nonplanar and variable material deposition based on the shape and geometric features of the topology-optimized parts. This allows for efficient use of material by placing it precisely where it’s needed for structural purposes, “and eliminates unnecessary overbuilding with excessive amounts of materials,” Aghaei Meibodi said. “All of these factors combined mean that we can build better, more environmentally friendly structures at a lower cost.”

In the age of robots, artificial intelligence and automation in architecture, 3D printing is gaining popularity in the construction industry, particularly for its ability to create complex shapes and structures quickly and with less waste.

Overall, the construction industry is beginning to quickly embrace 3D printing as a promising tool for innovation and sustainability.

According to Bayramvand and Lin, previous research has explored nonplanar 3D printing with polymer-based materials for intricate geometries, but using concrete—a more challenging material—has received limited attention.

With these technological advancements from the DART Lab researchers, notable leaders in 3D concrete construction—the Peri Group, ICON and WASP—are beginning to take notice.

With rapid urbanization and increased demands to build infrastructure, their work is contributing to major changes in the construction industry and overall 3DCP practices—establishing new partnerships designed to improve future outcomes for architects, lawmakers, 3D concrete printing startups and the concrete industry at large.