In the aftermath of major earthquakes, wars, or other disasters – and as aging buildings and infrastructure are replaced – heaps of concrete are often taken to landfills or turned into rubble for road construction.

For a more sustainable approach, experts from Flinders University and the University of Melbourne are developing a ‘value-added’ for old broken concrete to ‘recycle’ coarse aggregate to produce strong, durable, and workable concrete using a small amount of a secret ingredient: graphene.

The innovative method is gaining ground as new graphene deposits are discovered and extracted, driving down the cost of this raw material as the cost of cement and aggregates continues to rise, say the researchers.

They have tested results using a weak solution of graphene in recycled aggregates to produce potentially superior concrete to untreated recycled aggregates in cement-based mixes.

These methods are urgently needed in waste management, as demolition and construction products are expected to increase to nearly 2.6 billion tonnes by 2030 worldwide. At the same time, concrete production is contributing to climate change as greenhouse gas emissions and extraction methods increase ecological impacts.

Improving the quality of recycled concrete aggregates will also play a vital role in the quality, performance, and workability of recycled concrete aggregates, while reducing the environmental footprint.

«This new form of treated recycled concrete aggregates may be more expensive to produce at this time, but considering the circularity and life cycle of materials, costs are quickly decreasing,» states Dr. Aliakbar Gholampour of Flinders University, lead author of the new article in Resources, Conservation and Recycling.

Dr. Gholampour, Associate Professor of Civil and Structural Engineering at Flinders, says the success of the new method could also help meet the growing demand for construction materials worldwide.

Dr. Gholampour has filed a patent for the approach, along with co-author and lead researcher from the University of Melbourne, Dr. Massoud Sofi, Deputy Director (Research) of the Centre for Resources Recovered (CoRR).