Reflecting on a Decade: Developments and Outcomes of Alkali-Activated Concrete Innovations in Australia

This paper reports the findings of site inspections performed on two retaining walls built with geopolymer concrete in 2013. The retaining walls are located in Melbourne, Australia, and were built as part of dedicated trials in transport infrastructure projects to generate information on the long-term performance of geopolymers exposed to outdoor conditions. While geopolymers and alkali activated binders have reemerged in the market as part of decarbonisation of the concrete sector, the majority of the data available on the long-term performance of those materials was produced under controlled conditions. The evidence provided by this investigation is to support the continuous development of standards, advance the commercialisation of geopolymer concrete and provide confidence to designers, asset owners and engineers on the performance of such materials under real exposure conditions. A visual inspection was initially performed on both structures, followed by coring and sampling for the assessment of compressive strength, carbonation depth and pH, and apparent volume of permeable voids (VPV). Overall, the walls are both structurally sound, although some cosmetic superficial erosion was observed. No critical durability issues were found in the inspected structures, providing evidence of the long-term performance of alkali-activated concrete under field conditions. This paper will also share the latest developments on alkali-activated concrete in Australia.