Dezeen Magazine has reported that Australian Researchers have created a building material where rammed earth is encased in permanent cardboard formwork, eliminating the need for cement.
Rammed earth is a construction technique that involves compacting a mixture of moist soil, sand, gravel, and clay into formwork to create solid walls. The mixture is compacted in layers until it becomes a dense, durable, and monolithic wall once the formwork is removed. This ancient method has been revived for its sustainability, aesthetic appeal, and excellent thermal mass.
The new development is to keep the compacted earth confined within lightweight cardboard tubes. This can eliminate the need for cement, creating a low-carbon, lightweight, and thermally insulating composite that could be used for low-rise and modular buildings.
By combining rammed earth with cardboard into a new material called CCRE (cardboard-confined rammed earth), the researchers believe they can further reduce embodied carbon while also providing a useful recycling pathway for waste cardboard.
In conventional rammed earth construction, soil is compacted inside temporary formworks – usually made of plywood or steel – that give the wall its shape. Once the earth hardens, the formworks are removed, leaving behind a freestanding wall.
Today, buildings and construction materials like concrete and steel contribute 37 per cent of the world’s annual CO2 emissions. The cement industry alone is responsible for 8 per cent.
This has caused a reckoning among architects and engineers, who now seek low-carbon alternatives such as Mass Timber, Adobe and rammed earth.
Mass timber is a group of engineered wood products, such as Cross-Laminated Timber (CLT) and Glued-Laminated Timber (Glulam), made from smaller pieces of wood bonded together to create large structural components like beams, columns.
Adobe is a sustainable building material made from a mixture of earth, sand, clay, water, and an organic binder like straw or dung. The material is mixed into a thick mud, formed into bricks using moulds, and then sun-dried instead of being fired in a kiln.
An “ultra-low-carbon building resource”
At the same time, the use of cardboard as a packaging material has surged with the e-commerce boom, causing mounting waste management challenges.
In 2020 and 2021, for example, cardboard and paper accounted for 7.7 per cent of all waste generated in Australia, with a staggering 2.2 million tons sent to landfill.
“This creates both an environmental challenge and an opportunity,” Dr Jiaming Liu, one of the study’s lead researchers, told Dezeen. “Repurposing cardboard for construction not only diverts it from landfill but also transforms it into a valuable, ultra-low-carbon building resource.”
Repurposing cardboard for construction not only diverts it from landfill but also transforms it into a valuable, ultra-low-carbon building resource.
Next, the researchers plan to construct full-scale CCRE columns and to experiment with formworks that move beyond simple cylindrical shapes.
They envision foldable, origami-inspired cardboard moulds that could be transported flat and quickly assembled on-site, opening the door to custom, modular, and easily deployable construction systems.
This article is extracted from the Dezeen Magazine