Geopolymer concrete at Brisbane airport: 40,000 cubic metres poured without Portland cement

An airport pavement in Queensland shows what low-carbon concrete can do at full scale. In 2014, Brisbane West Wellcamp Airport used 40,000 cubic metres of geopolymer concrete made from slag and fly ash instead of ordinary Portland cement for sections thick enough to carry 747 cargo planes. The material skips the kiln step that makes cement so carbon-heavy, and the project reported roughly 6,600 tonnes of CO2 saved. More than a decade later, the pavement is still carrying scheduled freight. That matters because the hard part was never the chemistry. Building codes and supply chains are built around Portland cement, and one key ingredient, fly ash, depends on coal plants that are closing. The airport is a proof point, not yet a template.