Australian engineers create reusable building material emitting just a quarter of concrete’s carbon footprint

Engineers in Australia have unveiled an innovative building material, termed cardboard-confined rammed earth, comprised solely of cardboard, soil, and water. This new material eliminates the need for cement, reducing emissions to about one quarter of those from traditional concrete, while costing under a third as much.

The method works by compacting a soil-and-water mixture inside cardboard formwork, which can be produced on site and reused or recycled. Because heavy transport of conventional building materials is reduced, the approach is especially promising for remote or resource-limited regions.

In related experiments, the researchers combined carbon fibre with rammed earth and achieved strength comparable to high-performance concrete. The design also leverages the thermal mass of earth materials, naturally regulating indoor temperature and humidity-particularly suitable in hot climates.

Cement and concrete account for roughly seven to eight percent of global CO2 emissions, driven by the calcination chemistry of cement production and the sheer scale of built-environment construction. Alternative materials that can reduce embodied carbon at meaningful cost parity - as cardboard-confined rammed earth appears to - matter more strategically than their apparent simplicity suggests.

The design also embeds circular-economy principles: cardboard formwork can be produced on-site, reused across pours, or recycled at end of life. Combined with the earth's natural thermal-mass performance, the material offers a plausible pathway for lower-carbon construction in hot, remote or resource-constrained contexts - geographies where conventional concrete supply chains are both carbon-intensive and logistically costly.

For real estate, infrastructure and construction clients working toward Scope 3 or embodied-carbon commitments, Cognitud's circular economy and climate action teams help assess alternative-material portfolios, model embodied-carbon savings against LCA-based benchmarks, and structure procurement standards that give suppliers a clear commercial pathway to lower-carbon construction - moving embodied carbon from a reporting metric to an active procurement lever.