DEVELOPMENT OF BAYER GEOPOLYMER PASTE AND USE AS CONCRETE

The Centre for Sustainable Resource Processing (CSRP) (www.csrp.com.au/) had a vision of sustainable minerals processing, where global material needs are satisfied with significantly reduced impacts. One legacy of that vision has been the establishment of the Geopolymer Alliance (www.geopolymers.com.au/) and the continued development of geopolymers utilising industry co-products. Of particular interest here is the utilisation of bauxite refining co-products within geopolymer production.

Collaborative research between Alcoa of Australia Limited and Curtin University of Technology (Curtin) set out to investigate the use of Bayer process materials for the production of geopolymers. Secondly, if incorporation was possible, could the resulting paste be utilised as binder for concrete formulations.

Research was conducted over several years with the following outcomes.

• Sodium silicate activation solution could be replaced by a Bayer sodium aluminate solution without detrimental impact upon compressive strength.
• “Bayer Geopolymer” paste was refined from an oven cured product to ambient cure, with compressive strength in excess of 30 MPa.
• The ambient setting paste was applied to a concrete mix design, with resultant compressive strength in excess of 25 MPa.

Clearly there is opportunity for signifi cant synergy between the Bayer Industry and the Geopolymer Industry, with both having the potential to benefit. There is now also potential for other Bayer products (Mud, Sand, Lime etc.) to be included within the concrete mix design.