MELBOURNE, Australia—Scientists from RMIT University Melbourne City have successfully replaced 100 percent of conventional aggregates in concrete—such as gravel and crushed rock—with rubber from discarded tires.
The new "greener and lighter" concrete meets building codes, while reducing manufacturing and transportation costs significantly, according to a university statement Aug. 11.
According to the report, while small amounts of rubber particles are generally used to replace concrete aggregates, efforts to replace all the aggregates with waste tire rubber have until today produced weak concretes that failed to meet the required standards.
RMIT's technique involves using newly designed casting molds to compress the coarse rubber aggregate in fresh concrete that enhances the building material's performance.
"We have demonstrated with our precise casting method that this decades-old perceived limitation on using large amounts of coarse rubber particles in concrete can now be overcome," said lead author and Ph.D. researcher Mohammad Momeen Ul Islam.
Study co-author and team leader, Professor Jie Li, said this manufacturing process will unlock environmental and economic benefits.
"As a major portion of typical concrete is 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," he said.
The manufacturing process, according to RMIT, could be scaled up cost effectively within a precast concrete industrial setting in Australia and overseas.
Following successful testing in the workshop, the team is now looking into reinforcing the concrete to see how it can work in structural elements.
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