Taking a decisive step towards a circular economy in the construction industry, a team of engineers from RMIT University used rubber from discarded tires to create a new type of concrete. The new, greener and lighter concrete uses recycled tire rubber to replace all conventional aggregates such as gravel and crushed stone.
The study, published in the journal Resources, Conservation & Recycling, reveals that green concrete not only meets building codes, but also promises to significantly reduce manufacturing and transportation costs.
While small amounts of rubber particles from tires are already used to replace concrete aggregates, efforts to replace all aggregates with rubber produced weak concretes that did not meet required standards, the team said. .
According to lead author and doctoral researcher from RMIT University’s School of Engineering, Mohammad Momeen Ul Islam, their precise casting method demonstrates that the perceived limitation of using large amounts of coarse rubber particles in the concrete can now be overcome.
“The technique involves using newly designed casting molds to compress the coarse rubber aggregate into fresh concrete which improves the performance of the construction material,” Islam said.
Study co-author and team leader Professor Jie Li said this manufacturing process will unlock environmental and economic benefits.
“As much of the typical concrete is made up of coarse aggregate, replacing all of this with used tire rubber can significantly reduce the consumption of natural resources and also address the major environmental challenge of what to do with used tires,” did he declare.
The RMIT team’s study highlights the importance of finding a solution to the growing problem of scrap tyres, not just in Australia but around the world. Used tires in Australia cannot be exported, making new methods of recycling and reprocessing locally increasingly important.
With significantly reduced manufacturing and transport costs, the new concrete will benefit a range of developments, including low-cost housing projects in rural and remote parts of Australia and other countries around the world, said Li.
The team’s manufacturing process could be cost-effectively scaled up in an industrial precast concrete environment in Australia and overseas, Islam added.
The research team is now working on concrete reinforcement to see how it can work in structural elements.
The RMIT research team also includes Prof. Yu-Fei Wu, Dr. Rajeev Roychand and Dr. Mohammad Saberian.
Image: Concrete mix using recycled tire rubber particles as a complete replacement for traditional coarse aggregate. Credit: Mohammad Islam, RMIT