Advanced manufacturing of waste-integrated concrete roof tiles: Scaling up to TRL 6

This research examines the integration of pond ash and unwashed glass sand in concrete roof tiles. After successfully completing a laboratory-based trial with the optimal composition of 10 % pond ash and 10 % glass sand, a manufacturing trial was conducted in collaboration with a leading Australian roofing manufacturer to produce the concrete roof tile specimens. The optimized roof tiles met AS 2049–2002 standards for roof tiles, including transverse strength, water absorption, permeability, and salt attack. The waste-integrated concrete roof tiles were up to 5 % lighter and exhibited better performance under fire exposure compared to conventional roof tiles. Roof tiles incorporated with waste and exposed to 120 °C and 300 °C showed up to a 6 % increase in transverse strength, attributed to additional C-S-H formation. Although strength decreased at 600 °C and 800 °C under fire exposure due to thermal expansion incompatibility and a loss of bonding strength in the interfacial transition zone between the aggregates and matrix, waste-integrated roof tiles retained 11–13 % of their original strength, whereas conventional roof tiles retained only 6 % of their unexposed strength. The inclusion of pond ash increased alumina products, promoting additional Si-O-Al bonds and resulting in additional C-A-S-H formation. Pond ash also helped refine pores due to its micro filler effect and pozzolanic activity. However, incorporating more than 10 % recycled glass reduced performance, as its smooth surface weakened the bond between the cement matrix and the glass aggregates. Overall, the roof tile product explored in this study demonstrates strong potential as an eco-friendly concrete solution, offering notable advantages by mitigating the environmental impact of unwashed glass sand and pond ash. This waste-integrated concrete roof tile was successfully demonstrated in a real-world setting, achieving a Technology Readiness Level (TRL) of 6. • Integration of pond ash and unwashed glass sand in roof tiles were achieved. • Concrete roof tiles were produced and achieved a Technology Readiness Level of 6. • Concrete roof tiles met Australian standard and all product specifications. • Waste-integrated roof tiles was 5 % lighter than conventional tiles. • Waste-integrated roof tiles withstand up to 600 °C fire exposure.