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Concrete In Australia : September 2013
Concrete in Australia Vol 39 No 3 27 Overcoming barriers to implementation of geopolymer concrete Marita L. Berndt, Research Professor, Swinburne University of Technology and Associate, Aurecon Jay Sanjayan, Professor, Swinburne University of Technology Stephen Foster, Professor, University of New South Wales Kwesi Sagoe-Crentsil, Research Team Leader, CSIRO Manufacturing Science and Engineering and Professor, Swinburne University of Technology Craig Heidrich, Executive Director, Australasian Iron and Steel Slag Association and Chief Executive Of cer, Ash Development Association of Australia Geopolymer concrete offers potential advantages such as structural performance, reduced greenhouse gas emissions, as well as acid and fire resistance. However, despite these advantages widespread commercial use of geopolymer concrete in the construction industry has encountered numerous technical, economic and institutional barriers. With increasing concerns regarding climate change, designers are keen to use alternatives to ordinary Portland cement-based concrete, but face uncertainties regarding properties, performance and lack of compliance with AS 3600 and related standards. is paper describes ongoing work performed under the Cooperative Research Council for Low Carbon Living and pathways which need to be developed for increased acceptance and usage of geopolymer concrete in mainstream construction. Current definitions of concrete and the ways in which concrete is commonly specified are examined in order to find potential modifications to include geopolymer concrete. An industry survey was performed and this identified barriers specific to geopolymers and potential actions to overcome raised issues. Lessons from successful introduction of other alternative materials to the construction industry are also considered. 1.0 INTRODUCTION Construction of the built environment involves use of natural resources and creation of greenhouse gas emissions. As awareness of resource depletion and climate change grows, so too does the need for the construction industry to adopt more sustainable materials and technologies. Reduction in emissions can be achieved through appropriate material selection. However, widespread uptake of alternative materials has yet to occur. e Cooperative Research Centre (CRC) for Low Carbon Living aims to provide government and industry with social, technological and policy tools to overcome identified market barriers preventing adoption of alternative products and services, while maintaining industry competitiveness and improving quality of life. One component of the CRC research is to identify pathways for adoption of low CO2 emission concrete and contribute to reduction of emissions in the built environment. e objectives of this paper are to examine the current design and specification of concrete in Australia, and to consider how barriers to implementation of low CO2 concrete, specifically geopolymer concrete, can be surmounted. 2.0 CURRENT DEFINITIONS AND REQUIREMENTS OF CONCRETE IN STANDARDS AND SPECIFICATIONS 2.1 Definitions Alternatives to Portland cement concrete are being explored as a means of reducing CO2 emissions associated with construction (Gartner, 1). ese alternatives include alkali- activated slag and fly ash to form "geopolymers". In order to better understand how alternative concretes such as geopolymer materials may be integrated into existing standards and practices, it is useful to examine the conventional definitions of concrete. Traditionally, the term "concrete" is used in the engineering field to describe material using Portland cement as the binder. e definitions of concrete in commonly used standards and guides are summarised in Table 1. Salient points from Table 1 include the following: • AS3600,AS1379andAS5100,andBSEN206donot specifically nominate Portland cement. However, inclusion of water implies that the cement is hydraulic. • ASTM C 125 refers to a binding medium which could be