Recycled concrete aggregates offer significant environmental benefits. Because they can be made with a variety of materials they can repurpose waste that would otherwise end up in landfills, reduce carbon dioxide emissions, save natural resources and contribute to the circular economy. The challenge, however, comes from producing recycled concrete that is strong enough and durable enough to replace traditional concrete in practical applications.

A new method for casting prefabricated concrete products addresses this issue. Researchers from RMIT University, Australia, and Shenzhen University, China, developed the rubberized concrete processing technology (RCP-Tech) using rubber tires and waste from construction and demolition. The result is as much as 35% stronger than traditional concrete and provides an efficient and inexpensive solution to the problem of construction waste.Source: RMIT University

"This technology can be used to significantly improve the strength, hardness and durability of any type of concrete material, such as rubber concrete, recycled aggregate concrete, and even ordinary concrete," said Professor Yufei Wu, RMIT University School of Engineering, who led the development of RCP-Tech.

To create the new concrete, a mix of coarse and fine aggregates are combined with rubber tire waste, cement and water. The mixture is compressed in a customized mold to its minimum volume using pressure.

Rubber waste, specifically from tires, is a major source of health, environmental and landfill problems globally because its chemical makeup renders it flammable and non-decomposable. In one year alone, 2015-2016, Australia generated approximately 450,000 tons of waste rubber, and 63% of that went to stockpiles and landfills.

According to Syed Kazmi, Ph.D. researcher and co-creator of RCP-Tech, the team is looking to work with the precast concrete industry to create and test prototypes of specific products such as blocks, roadside barriers, wall panels, beams and slabs.

"The technology can be easily applied in the precast concrete industry and requires very little change to existing manufacturing processes with the addition of just one extra step in the final stage of production," Kazmi said.

The research findings are published in the journal Resources, Conservation and Recycling.