From used coffee cups to building rubble and everything in between, recycled waste has been utilised to create concrete products that promise several environmental benefits. While recycled concrete aggregates contribute to reducing landfill and CO2 emissions, save natural resources and boost the circular economy, challenges still remain in matching the strength and durability of traditional concrete, hindering their practical application.
The concept of ‘sustainable concrete’ just got a major boost with RMIT researchers developing a new technology to produce stronger, more durable and sustainable concrete products from a mix of rubber tyres and construction and demolition waste. Prefabricated concrete products cast using the new technology are up to 35% stronger than traditional concrete.
Professor Yufei Wu from RMIT’s School of Engineering, who led the development of the Rubberised Concrete Processing Technology (RCP-Tech), explained that it offered an efficient and inexpensive solution 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.
The method involves combining a mix of course and fine aggregates with rubber tyre waste, cement and water, and then compressing the mix to its minimum volume using pressure in a customised mould.
“By enhancing the properties of the recycled waste without the use of any additional materials, we have developed a feasible and practical solution that addresses the performance issues affiliated with waste recycling in concrete,” Wu said.
Used and discarded tyres are a major cause of significant health, environmental and landfill problems worldwide, owing to the rubber waste’s chemical, flammable and non-decomposable nature. From 2015-16, Australia generated around 450,000 tonnes of waste rubber, 63% of which was sent to stockpiles or landfills. Victoria alone produces the equivalent volume of the Eureka Tower every four years.
The RMIT research team is exploring partnerships with the precast concrete industry to manufacture and test prototypes of products such as blocks and roadside barriers, wall panels, beams and slabs, says PhD researcher and RCP-Tech co-creator, Syed Kazmi.
“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,” he said.
Kazmi and fellow PhD researcher Muhammad Munir presented the game-changing technology at the City of Melbourne Open Innovation Competition 2020 where they were finalists. They were also awarded the RMIT LaunchHUB prize for their work.