CRC-LCL impact pathway 2 summary report: delivering low carbon materials, products and designs

Building materials Embodied carbon Emission reduction Australia

Global warming is considered to be an issue of national and international significance and, if left unattended, a threat to future standards of living as well issues such as biodiversity and adaptability of the planet’s sensitive eco-systems. Realising the severity of this issue, nations came together and agreed to act quickly to mitigate the worst of these effects through the Paris Agreement and set out clear and decisive targets for decarbonising so as to keep the global average temperature rise to well below 2 degrees Celsius above pre-industrial levels. Building and construction materials contribute one third of global greenhouse gas emissions (GHGE) and, despite having only 0.33% of the world’s population, Australia has one of the highest per capita pollution and emission intensity levels.

Buildings produce a significant amount of carbon in their day-to-day use, with operational emissions from the built environment contributing an estimated 20% towards Australia’s annual national total. Carbon mitigation strategies and standards developed by industry and government generally focus on these ‘direct emissions.’ Another important part of the picture is the carbon emissions created during other stages of a building’s life, such as in the production of materials and in construction. This ‘embodied’ carbon contributes an additional 18% towards Australia’s overall emissions, making it an important focus for new research and an enormous opportunity to boost built environment carbon reductions. Reduction in emissions can be achieved through appropriate material selection. As awareness of resource depletion and climate change grow, so too does the need for the construction industry to adopt more sustainable materials, technologies and practices. However, widespread uptake of alternative materials has yet to occur.

The Cooperative Research Centre for Low Carbon Living (CRCLCL) was launched in 2012 and aimed 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.

As part of the CRCLCL Program 1: Integrated Building Systems, Impact Pathway 2 aims to lowering the embedded carbon in buildings through developing low-carbon-lifecycle building construction components or materials. With these objectives CRCLCL undertook several projects to lower the embedded carbon in built environment. Its outputs target next generation construction practices, where step-change emission cuts are required and use of alternative carbon neutral materials needed. The Integrated Carbon Metrics (ICM) project aimed to build knowledge about both the direct and indirect carbon emissions in the building process and to better inform those making decisions about our future built environment. The ICM project developed carbon accounting tools that can scale to the building, precinct or city level, to provide a holistic picture of the carbon lifecycle in the Australian built environment. Carbon value engineering (VE) project verifies the current VE practices and has developed new method for carbon VE that account for entire life cycle of building materials. Other projects have successfully developed sustainable building materials from waste materials.

Portland cement is a major contributor to the total embodied emissions of building materials and thus recent research has been directed at improving the sustainability of cement-based products such as concrete and mortar. The use of supplementary cementitious materials such as fly ash and granulated ground blast furnace slag to improve properties and reduce the CO2 impact of concrete is now well established. Further reductions in emissions are feasible with the use of alternative binders to Portland cement. One such binder is based on aluminosilicates and commonly termed ‘Geopolymer’ or ‘Alkali Activated Binders’. One component of the CRC research was to identify pathways for enhancing the commercialisation opportunities of low CO2 emission concrete and contribute to reduction of emissions in the built environment.

This report summarises the CRCLCL projects relevant to Impact Pathway 2- lowering embodied carbon, highlights the outcomes of each and draws relevant interconnections.

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