Bridges

Cover of Geopolymer Green Concrete: Reducing the Carbon Footprint - The VicRoads Experience
Geopolymer Green Concrete: Reducing the Carbon Footprint - The VicRoads Experience
  • Publication no: ABC-SAS005-11
  • Published: 31 October 2011

Geopolymer concrete consists of the normal components of fine and coarse aggregate, any required admixtures and aluminosilicate based industry byproducts such as fly ash and ground granulated blast furnace slag which can be activated with a concentrated solution of alkali-based chemicals such as sodium hydroxide and sodium silicate in water to form the binder (glue) in this new material. Geopolymer concrete was developed in the old Soviet Union in the 1950’s and used in the form of soil cement, alkali activated cement and acid cement. The name geopolymer was first applied to these materials by Joseph Davidovits in France in the 1970s.

Over the past 10 to 15 years, significant amounts of research on geopolymer concrete has also been undertaken at a number of Australian universities particularly in Victoria and Western Australia mainly under laboratory controlled conditions without any significant on-site field work. In more recent times, the need to reduce the carbon foot print in the construction sector is helping with the marketing, manufacture and supply of geopolymer concrete in some parts of Australia, particularly for low risk general paving works.

In an effort to obtain a greater understanding of the practical potential of geopolymer concrete VicRoads has over the past two years undertaken a small number of trials which include the in-situ construction of landscape retaining walls at a bridge site, precast footway panels on a bridge and construction of a significant length of footpath. These trials form part of a strategy to generate a greater understanding on long term performance particularly with respect to higher risk structural applications, which includes visual inspection, sampling and testing and monitoring of embedded probes. At this stage VicRoads has gained sufficient confidence with regards to low risk general paving works (i.e. footpaths, driveways, kerb & channel and other concrete surfacings) and has incorporated geopolymer binder concrete into its general concrete paving specification Section 703 as an equivalent product to Portland cement concrete.