• A Charles Sturt researcher and colleagues have found that using clay can significantly improve the strength of stabilised peat
• Their study found that stabilising peat with clay in building foundations can significantly reduce the amount of cement used by more than 40 percent
• It confirmed that clay can partially replace cement for effective and eco-friendly peat stabilisation, lower carbon emissions and will inform engineering practice

A Charles Sturt University academic has been part of a world-leading research team that has identified a way to replace carbon-intensive cement by using clay as a lower-carbon replacement in construction.

Senior Lecturer in Civil Engineering in the Charles Sturt School of Computing, Mathematics and Engineering Dr Miao Li (pictured inset) said, “This study is the first step to help tackle one of the world’s biggest polluters ─ cement ─ and it will inform engineering practice for peat stabilisation to help contribute to the global target of carbon neutrality by 2050.”

Dr Li explained that using cement for peat and soft soil foundation stabilisation has been a traditional engineering practice, however cement production is a highly energy-intensive process and causes significant carbon emissions.

“Our study describes a series of laboratory experiments that demonstrate the benefits of using clay as a natural and environmentally-friendly material to partially replace the use of cement for peat stabilisation and thus reduce carbon emissions,” Dr Li said.

“We are very proud that we came up with this idea of using clay to partially replace cement in peat stabilisation, and we were able to devise experiments to test its feasibility.”

Dr Li said using only cement to stabilise peat would require 20.8 per cent of cement, but by adding 40 per cent of clay, the cement consumption is reduced to 12 per cent ─ a 42.3 per cent saving ─ to stabilise the same peat.

“Even though this engineering application is not highly relevant for applications in Australia, since we don’t build on peat in Australia because we have so much land we don’t need to, it is applicable elsewhere,” she said.

“It shows what research can do to help achieve the UN Sustainable Development Goal (SDG) 13: climate action.”

Dr Li said she and her research colleagues are exploring other innovative ways for a broader range of application and expect more practical findings.

“This is a developing stage of a project that focuses on reducing carbon emissions in cement in foundation treatment.

“The next stage of research is to work with clay and a large number of soils that are considered to be problematic in engineering, for example collapsible soils, expansive soils, peat, silty soils, and liquefiable soils.”

The research, ‘Incorporating clay as a natural and enviro-friendly partial replacement for cement to reduce carbon emissions in peat stabilisation: an experimental investigation’, is published in the journal Construction and Building Materials (Volume 353, 24 October 2022, 128901) (which is ranked 8th out of 193 construction engineering journals worldwide). Dr Li is based in Bathurst, and her fellow researchers are based at the Kunming University of Science and Technology in China.