As part of the City of Sydney’s ongoing commitment to reduce the amount of carbon emissions in the atmosphere, a new category of concrete is being used on a trial basis in Alexandria, Sydney.

As part of a global first green road trial, a 15-metre stretch of Wyndham Street has been laid with Geopolymer concrete, culled from industrial waste produced at coal-fired power stations and steel manufacturing plants. The City is testing this sustainable mixture of concrete and recycled materials on an active busy inner-city street boasting nine sensors placed beneath the concrete for purposes of assessment and monitoring. And for comparative purposes, the street also is laid with a full 15 metres of traditional concrete.

Wyndham Street is a primary road that leads to Sydney Airport, and thus produces the elevated volume of traffic required for the trial.

UNSW Sydney researchers and the CRC for Low Carbon Living (CRCLCL) will apply all green road trial results to cultivate the premiere set of industry guidelines in regards to Geopolymer concrete.

Lord Mayor Clover Moore asserted that the City of Sydney was Australia’s first carbon-neutral local government, and as such has a firm commitment to reduce the city’s carbon footprint. The Geopolymer project, in her view, could do much to reduce carbon emissions.

Consisting of industrial wastes like fly ash and blast furnace slag, Geopolymer produces only 300 kilograms of CO2 per tonne of cement, in comparison to the 900 kilograms generated through traditional cement production. Coal and steel industries around the globe generate approximately 400 million cubic tonnes of waste, the majority of which is kept on site. The Geopolymer project presents a possible constructive use for this waste.

UNSW Sydney researchers will monitor this trial and its results for up to five years. Professor Stephen Foster, head of School of Civil and Environmental Engineering and the CRCLCL project lead, said that this trial will be conducive to change.

According to Foster, Geopolymer research has taken place since the 1990s but is just now being commercialised. Data generated during the first three months to a year of the trial will go toward confirming the success of project models and adding strength to predictions.

Industry partner Craig Heidrich, executive director of the Australian (Iron and Steel) Association and Ash Development Association, asserts that their collaboration with entities like the City of Sydney, along with the publication of the research findings, will well promote the incorporation of Geopolymer concrete in construction projects.

Dr Tommy Wiedmann, associate professor of sustainability research at UNSW, predicts that the replacement of standard concrete with Geopolymer concrete would save an average of 12,000 kilotons yearly.