Sunscreen for roads

Rubber from used tyres acts like sunscreen for roads and halves the rate of sun damage when mixed with bitumen, new research has found.

RMIT University engineers collaborated with Tyre Stewardship Australia (TSA) to reveal a bitumen blend that is both UV-resistant and withstands traffic loads, with the potential to save governments millions on road maintenance annually. Unlike much outdoor infrastructure – such as playground equipment and outdoor furniture – roads are not designed with any sun protection, making them prone to cracking and potentially unsafe to drive on. Australian states and territories spent nearly $2.9bn on road maintenance in 2019–2020, according to the National Transport Commission. The invention also provides a promising sustainable solution to Australia’s used-tyre crisis. Used tyres in Australia have been subject to an export ban since December 2020, which means new methods for recycling and reprocessing them locally is increasingly important. While research efforts have focused on improving the durability of roads in terms of traffic load, thermal ageing and weather-related events, sun damage has received little attention – until now. The new study led by Associate Professor Filippo Giustozzi at RMIT University provides a sustainable solution to UV protection for roads, with results published in the Journal of Cleaner Production. “We found that the ageing trend is actually slowed down when you add crumb rubber, which is recycled from scrap tyres, into the top layer of a road,” Giustozzi said. “This acts so effectively as a sunscreen for roads that it actually makes the surface last twice as long as regular bitumen. We knew that UV would be a factor in road degradation, but not by what degree or how to protect against it, as nobody has really been looking at this aspect.” RMIT is one of the few universities in Australia to have a UV machine for asphalt studies, which can simulate weather-related ageing and is usually used for testing outdoor furniture paints. Giustozzi’s team used this machine to simulate the long-term effect of solar degradation in the lab on bitumen with different concentrations of crumb rubber: from a low concentration of 7.5% to a medium of 15% and a high of 22.5%. After a month and a half of continuous exposure in the UV machine – equivalent to about a year of Melbourne’s UV radiation – they measured the changes in bitumen’s chemical and mechanical properties. Giustozzi said bitumen mixed with the high concentration of crumb rubber from recycled tyres showed 50% less UV damage compared to regular bitumen. While using more rubber was better in terms of UV resistance, Giustozzi said it was also important to balance this with mechanical performance. “You don’t want something that is UV resistant but not truck resistant,” he said. “We found adding between 18% and 22% of crumb rubber generates an ideal balance in terms of improving rut and fatigue resistance to traffic loads, while resisting UV ageing.” A sustainable solution to Australia’s used tyre crisis Used tyres in Australia cannot be exported, making new methods for recycling and reprocessing them locally increasingly important. But TSA CEO, Lina Goodman, said while Australia produced around 450,000 tonnes of end-of-life tyres in 2021, only around 70% of those were recycled or reprocessed, making it a critical problem to solve. “We are encouraged by the research in showcasing the viability and benefits of using crumb rubber from end-of-life tyres, not only in roads and civil infrastructure, but across multiple sectors,” Goodman said.

Associate Professor Filippo Giustozzi is a leading road engineer focused on delivering practical and readily implementable research outcomes. Credit: RMIT

The UV machine used during testing. Credit: RMIT

“We’re excited to collaborate on this project with industry and leading researchers at RMIT University. A multi-organisational approach paves the way for innovation and the opportunity to turn this resource into a value-added product.” Giustozzi said an added advantage of crumb rubber was that it was already widely in use, including in some roads, but that the councils and state authorities using it were not aware of this ‘sunscreen’ effect revealed in the research. “We hope this research will change that and open new opportunities,” he concluded.

tyrestewardship.org.au

Capral makes solid climate pledge

Capral has committed to reach net zero emissions by 2050. This target will be based on achieving net zero Scope 1 and Scope 2 emissions and is underpinned by emerging and breakthrough technology options.

The scientific community has clearly stated the need to reach net-zero global CO2 emissions by mid-century to limit global warming to 1.5°C and to reduce the destructive impacts of climate change on human society and nature. As a major aluminium supplier, Capral’s buying strategies and corporate activities will demonstrate the goal for Capral to work towards sustainability best practice underpinned by a commitment to the United Nations SDGs. Capral recognises that in the world in which we all live, the company must act wisely to protect the environment and the broader society while working in the interests of stakeholders and customers. “We have an absolute commitment to our staff, customers, stakeholders and the communities within which our facilities operate to ensure we are eliminating sources of emissions within the value chain of our business,” says Michael O’Keefe, General Manager – Marketing & Technology, who oversees Capral’s National Sustainability Committee and roadmap. Organisations around the world are recognising that this is a decision that cannot wait any longer and Capral is no different, we are proud to make this commitment and confident in our ability to achieve it.” O’Keefe explains that Capral’s Net zero commitment will in the first instance focus on Scope 1 and Scope 2 emissions. Scope 1 emissions are direct emissions from company-owned and controlled resources. In other words, emissions released into the atmosphere as a direct result of a set of activities, at an operational level. Scope 2 emissions are indirect emissions from the generation of purchased energy, from a utility provider. In other words, all Green House Gas (GHG) emissions released in the atmosphere, from the consumption of purchased electricity and gas. “Our focus is very much on eliminating the source of emissions. We intend to do this by improving our plant and equipment, implementing new technologies and embracing more sustainable practices across our organisation. Working with our upstream supply partners we will continue to look for options to incorporate more low carbon aluminium in our value chain and where feasible embrace circularity principles,” says O’Keefe. Reaching net-zero emissions will also require neutralising Capral’s residual GHG emissions with an equivalent amount of carbon removals. Capral recognises that an effective neutralisation strategy involves removing carbon from the atmosphere and storing it for a long-enough period to fully neutralise the impact of any GHG that continues to be released into the atmosphere. As an overarching safeguard, Capral also recognises the United Nations Sustainable Development Goals (SDGs) as a shared blueprint for peace and prosperity for people and the planet. “In recognising the UN SDGs, we implement environmental and social safeguards in our operations and decision-making process to ensure we continue to develop our position as a socially and environmentally aware organisation,” O’Keefe adds. Capral recognises that robustness and transparency are essential to the net zero 2050 commitment and will continue to disclose environmental impact and progress towards achieving their Net Zero target publicly as part of their annual and midyear reporting cycles.

capral.com.au

Zinc-bromine flow batteries

Redflow is pleased to announce that after extensive testing, their zinc-bromine flow battery energy storage solution can be used with Sol-Ark’s hybrid inverters.

Sol-Ark, based in Texas, USA, is a solar and energy storage technology company building innovative inverters that effectively manage solar panels and batteries used to create reliable on and off grid applications. Sol-Ark’s product line is UL-1741-SA certified, fully approved for grid connection in the US including meeting the demanding grid connection standards that apply in California. The integration testing was completed at the Redflow Integration and Testing facility in South Australia by Redflow’s Battery Management System architect, Simon Hackett and demonstrates complete compatibility between Redflow’s ZBM3 zinc-bromine flow battery and Sol-Ark’s product line of advanced hybrid inverters for solar PV and energy storage. Redflow CEO and Managing Director, Tim Harris said he was pleased that Sol-Ark’s North American codeapproved products are now certified to be integrated with their energy storage system and believes that this is an important step in the execution of their US growth strategy. “Integration with Sol-Ark’s well established product line enables Redflow to deploy its zinc-bromine flow batteries in the United States SME and C&I markets, creating exciting opportunities for Redflow and Sol-Ark to work together to deploy new smaller scale systems across the US, and deliver sustainable and environmentally friendly renewable energy storage solutions," Harris said. The Sol-Ark 5K, 8K, 12K and 15K products integrate solar PV arrays, 48V DC battery storage, grid and generator connections in a single cost-effective, outdoor-capable, wall-mounted device. For larger storage systems, up to 12 Sol-Ark devices can be clustered together to service large site deployments, like manufacturing plants or offices. Tom Brennan, founder, CEO and CTO of Sol-Ark is pleased to see the successful completion of integration testing as he sees the potential role of flow batteries to be an important part of the future energy storage eco-system. “Our compatibility with the innovative Redflow zinc-bromine flow battery demonstrates just how adaptable and powerful our platform is. From small to large commercial installations, our innovative product range is the enabler of scalable and sustainable renewable energy deployments in this rapidly growing market,” Brennan said. Redflow’s 10 kWh 48V ZBM3 is the world’s smallest production zinc-bromine flow battery. It is non-flammable, can operate at high temperatures, and uses easily sourced and fully recyclable components. It can be charged to 100% and discharged to 0% every day. With the ability to easily combine in parallel multiple ZBM3’s to deliver any required energy storage size. “The integration testing between Sol-Ark’s product line and Redflow’s batteries was simply seamless. With a simple CANBus connection between the Redflow BMS and the Sol-Ark inverter, everything just … works,” Hackett said. sol-ark.com