Concrete goes green
In a first for Australia, James Cook University engineers have swapped steel reinforcing for plastic waste and look set to drastically reduce the environmental cost of concrete.
JCU’s Dr Rabin Tuladhar found that short pieces of recycled plastic can be added as reinforcement in concrete, removing the need for steel mesh in concrete footpaths and precast elements such as drainage pits and concrete sleepers.
He said that the use of recycled plastic waste in concrete makes a huge difference towards making it more environmentally friendly.
“Using recycled plastic, we were able to get more than a 90 percent saving on CO2 emissions and fossil fuel usage compared to using the traditional steel mesh reinforcing. The recycled plastic also has obvious environmental advantages over using virgin plastic fibres.”
Dr Tuladhar’s team has conducted successful strength and durability tests on the precast concrete elements made with the recycled plastic fibres. Talks are now underway with concrete producers and local and federal governments on how to employ the new findings.
Dr Tuladhar’s work is focused making concrete production more sustainable. It includes other aspects such as replacement of natural sand with 100 percent crusher dust, a by-product of stone quarries, and the replacement of cement with up to 30 percent mining waste.
Concrete is the second most-used material on earth, second only to water.
More than 25 million cubic meters of concrete are poured annually in Australia.
Production of cement, a key ingredient of concrete, produces 900kg of CO2 for every ton of cement and is responsible for 5% of total annual global CO2 production.
The total consumption of polypropylene – the kind of plastic used in Dr Tuladhar’s tests - was around 220,000t in 2013 in Australia, from which only 21% was recycled.
Dr Rabin Tuladhar
College of Science, Technology & Engineering
P (07) 478 15381