Green roof tiles made of Coal ash and glass waste cut CO2 by 13%

RMIT University engineers, in collaboration with Bristile Roofing, have developed sustainable concrete roof tiles made from coal ash and recycled glass waste, two abundant Australian industrial byproducts that typically end up in landfills. By replacing 10% of cement with pond ash from coal-fired power stations and 10% of river sand with unwashed glass waste, the team produced lighter, fire-resistant roof tiles that meet Australian standards for strength and durability. A full life cycle assessment revealed these tiles reduce carbon dioxide emissions by 13% compared to conventional tiles, covering the entire production and disposal process. The project addresses significant waste challenges, as Australia produces around 12 million tonnes of coal ash and 1.3 million tonnes of glass waste annually. The innovative mix also demonstrated improved dimensional stability, reduced shrinkage cracking, and ongoing strength gain, making it suitable for roofing applications in Australia’s climate. Beyond roof tiles, the researchers adapted the mix to create eco-friendly bricks containing up to 35% waste materials,