The University of Sydney states that its researchers have poured ‘green’ cement pavement consisting of fly ash, and waste materials such as ground glass and gaseous carbon dioxide.
In comparison with traditional concrete, the basic pour of the slab salvaged:
- 52kg of sand from being dredged
- 327kg of carbon dioxide being released into the atmosphere.
- (during production) the equivalent energy of 1,000 cups of coffee or driving a car over 1,800km.
Across the globe, concrete is the most frequently utilised human-made product because of its use as a structural material in buildings and infrastructure.
Its advantages include durability; resistance to fire, weather and flood; sound thermal performance; flexibility and prospects for reuse and recycling.
Yet the material bears an extensive carbon footprint because of the carbon intensive nature of cement manufacture.
And its creation involves sand and aggregate dredging, which plays a major role in erosion and environmental degradation.
Director of the Waste Transformation Research Hub and School of Chemical and Biomolecular Engineering researcher, Professor Ali Abbas , stated that the cement was designed to counteract the ecological effect of conventional concrete construction.
Abbas said that he—in partnership with Delta Electricity and IQ Renew, construction materials and industrial minerals supplier Morgan Ash: an Adbri Company, to develop a less energy intensive alternative to concrete.
The concrete is culled from a cement that includes fly ash – a by-product of coal combustion – and waste glass, which is energy-intensive to recycle.
According to Abbas, about 12 million tonnes of fly ash are produced annually in Australia. In the green concrete, fly ash serves as a cement replacement.
Glass has conventionally been a costly and energy-intensive material to recycle. Less than half of the 1.4 million tonnes of glass created yearly in Australia is recycled. When crushed, glass can take the place of sand and aggregates in green concrete.
The team also is testing an algorithmic intelligence technique that adapts the concrete blend to particular applications.
Gaseous carbon dioxide is sequestered or “locked” into the concrete in a stable mineral state, which keeps greenhouse gases from penetrating the atmosphere.
The researchers said more environmental benefits could be derived when put into place on a larger scale. They plan to install two additional eco-pavements on campus with different blends to advance their trial studies.
Over the next year the team will watch the concrete’s performance, with the aim to make the technology commercial and get it on the market as an alternative to conventional concrete.
Fly ash can be reused under the NSW resource recovery plan.