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Concrete In Australia : September 2013
Concrete in Australia Vol 39 No 3 31 e development of performance-based standards was supported by Duxson and Provis (5) for greater acceptance of low CO2 concrete in general, along with acceptance by consulting engineers. With respect to consulting engineers, architects and clients may have interest in alternative concrete, but approval by conservative and risk-averse engineers can prevent use in projects. If appropriate standards and specifications are developed at state and national levels, in addition to long-term durability data, then the obstacle presented by consulting engineers could be overcome. Inclusion of geopolymers in VicRoads standards represents significant progress in this regard. 5.2 Industry survey on pathways and applications e industry survey performed as part of the CRC work also asked participants whether particular actions would assist in overcoming barriers to implementation of geopolymer concrete and what applications are likely to see widespread use in the near future. e responses are summarised in Figures 4 and 5. e key action to overcome barriers rated by 65% of respondents was the development of standard specifications for geopolymer concrete (Figure 4). More research on engineering properties and long-term durability, inclusion in state/local specifications and development of new Australian standards specific to geopolymer concrete were rated very highly (>50%). Improving the cost competitiveness compared with conventional concrete and increased availability of suitable products were regarded by more than 40% of respondents as appropriate actions. More field demonstrations, seminars and workforce training and greater recognition of environmental reward schemes (e.g. Green Star, LEED) were of moderate importance (30.0-37.5%). Development of performance-based standards and modification of existing standards and design methods were regarded as of less importance than development of new standards. Other responses included removal of trademarks and patents, independent research, demonstration in low-risk applications (footpaths, retaining walls) and a program to help develop the product on a site by site basis. e survey also asked what applications were likely to offer highest volume use of geopolymer concrete in the near future. e responses are shown in Figure 5. Precast (60%) and non- structural applications 50%) were rated highest, along with footpaths or bike/shared paths (47.5%). Moderately rated applications (>30%) were chemical and fire resistant uses, pipes, residential slabs/driveways, bricks or masonry blocks and railway sleepers. Roads and industrial slabs received responses in the 20-30% range. Other suggested applications were mine backfill, sewerage infrastructure (pipes, manholes, digestion tanks and school/government buildings and infrastructure. From the survey and review of prior studies, it is suggested that the highest priority actions to increase the use of geopolymer concrete in Australia are: • development of standard specifications for use by engineers • development of new standards specific to geopolymer concrete that include performance requirements • provision for use of geopolymer concrete in state and local specifications • more independent research on engineering properties and long-term durability to reduce risk. ese actions should be accompanied by ongoing education and training, field demonstrations, cost reductions and greater availability. Issues relating to product variability, intellectual property, conflicting greenhouse gas data, and control by cement and concrete suppliers also need to be addressed. In the near-term, efforts should concentrate on gaining acceptance for geopolymer concrete through production in controlled environments (i.e. precast) and either low risk, non- structural applications or applications where superior properties of geopolymer concrete are advantageous. 6.0 EXAMPLES OF PATHWAYS FOR OTHER MATERIALS In discussion of new and innovative materials in general, Maine et al (10) noted the long period of gestation (typically around 20 years) before widespread acceptance and substitution. For materials proposed for substitution into a Figure 4. Responses to "What actions do you think should be taken to overcome the barriers to implementation of geopolymer concrete? (Tick all that apply)" Figure 5. Responses to "What applications do you think offer the highest volume use of geopolymer concrete in the near future? (Tick all that apply)". Response (%) 010203040506070 Seminars/workforce training Develop standard specifications Modify design methods Modify existing standards Develop new standards Performance-based standards Inclusion in state specifications Financial incentives Environmental reward schemes More cost competitive Research on properties/durability More field demonstrations Monitor in-situ performance Risk management Increased availability Improved safety Other 30.0 65.0 22.5 35.0 47.5 30.0 52.5 20.0 32.5 45.0 55.0 37.5 15.0 10.0 42.5 12.5 10.0 Response (%) 0 10203040506070 60.0 50.0 47.5 37.5 20.0 27.5 37.5 30.0 15.0 37.5 40.0 40.0 15.0 12.5 17.5 Precast Non-structural Structural Footpaths/bike/shared paths Residential slabs/driveways Industrial slabs Roads Pipes Railway sleepers No-fines concrete Fire resistant applications Chemical resistant applications Hazardous waste stabilisation Bricks, masonry blocks Other