Finding substitutes for portland cement has recently emerged as one of the most widely investigated means for raising the sustainability and efficiency of concrete production.
Instead of replacing portland cement, however, researchers from James Cook University have teamed up with Queensland's Fibercon to create a process for converting industrial plastic waste into an effective substitute for the steel matrices used in reinforced concrete.
"We've produced recycled polypropylene fibres from industrial plastic wastes," said Dr. Rabin Tuladhar, who supervised the development of the technology by JCU PhD student Shi Yin. "With our improved melt spinning and hot drawing process we now have plastic fibres strong enough to replace steel mesh in concrete footpaths."
The new technology solves two major environmental challenges in a single fell swoop; it disposes of industrial plastic waste by recycling it in concrete, which in turn dramatically reduces the carbon footprint of the world's most widely used building material by dispensing with the need to produce energy-intensive steel.
"Using recycled plastic, we were able to get more than a 90 per cent saving on C02 emissions and fossil fuel usage compared to using the traditional steel mash reinforcing," said Tuladhar. "The recycled plastic also has obvious environmental advantages over using virgin plastic fibres."
According to a comprehensive life cycle assessment conducted by the researchers, the use of recycled plastic fibre results in 90 per cent less carbon dioxide emissions than production of the equivalent steel amount while also dramatically reducing water pollution in the form of eutrophication.
The technology has already earned plaudits from local industry, winning the Manufacturing, Construction and Innovation category at the 2015 Australian Innovation Challenge.
The JCU researchers are currently looking at other substitute materials that could be used to raise the sustainability of concrete, including the partial replacement of portland cement with the pitchstone dust generated by mining in the North of Queensland.