(591c) Geopolymer Technology and the Search for a Low-CO2 Alternative to Concrete

One of the largest single-industry contributions to worldwide anthropogenic CO₂ emissions is due to the manufacture of Portland cement, which releases around 0.8 tonne CO₂ per tonne of cement production. Various means of reducing this impact have been proposed, in particular the use of high-volume supplementary cementitious materials (SCMs ? usually coal fly ash or blast furnace slag). However, the replacement of up to 40% of the Portland cement content of concrete with ash or slag tends to have deleterious effects on the properties of the material, with slow strength development being a common drawback. Geopolymer concrete, synthesized at 100% SCM content by the use of an alkaline activator solution, provides a very attractive alternative to Portland cement concrete due to its comparable physical and mechanical properties and rapid, controllable strength development. Furthermore, the CO₂ emissions due to geopolymer synthesis are approximately 80-90% lower than traditional Portland cements. Recent developments in the commercial-scale production and utilization of geopolymer concrete as a means of enhancing the sustainability of the Australian construction industry will be presented, as well as significant technological advances in this field.