There is much room for improving the sustainability of the construction industry through the use of new materials. Texas A&M University researchers maintain that an environmentally acceptable substitute for concrete production, which accounts for 8% of global carbon dioxide emissions, is available everywhere. Schematic representation of a proposed process flow for in situ soil utilization. Source: Aayushi Bajpayee et al.Ordinary soils, particularly those with high clay content, could be processed to yield a material with properties similar to concrete.

A new class of construction materials could be produced on-site using local soils as additive manufacturing feedstock. A process is outlined in Forntiers in Materials to modify naturally sourced materials to be extrudable, compactable and cross-linkable with rapid strength gain as needed for construction of load-bearing structures.

The researchers optimized a common local clay for extrusion from a 3D printer by creating a cross-linked siloxane framework that could bind clay particles together. The benefit of such material is that it could reduce the carbon footprint of transporting construction materials long distances. The technology was also demonstrated by harvesting acidic boreal soils for road construction in Alberta, Canada, and synthesizing clay-incorporated concrete for oil-well cementing.

The material produced is currently best suited for nonstructural elements, but efforts are underway to optimize the approach and produce stronger materials that can flow through giant 3D printers while keeping the industry’s carbon footprint in check.