Large transport megaprojects generate material streams of a scale rarely encountered in standard construction. Melbourne’s North East Link (NEL) tunnels will produce an estimated 4–6 million m³ of spoil and 150,000–300,000 tonnes of mixed construction waste, including 8,000–15,000 tonnes of reusable timber and 400–1,200 tonnes of PPE polymers and textiles. These flows are often treated as linear waste streams despite their circular potential. This study examines how such a one-off material pulse can be redirected into lasting circular value through targeted spoil characterisation, practical reuse pathways and coordinated industry engagement.
Framing NEL as a living laboratory, the work focuses on shifting spoil and construction waste from liability to strategic input. Proposed pathways include geopolymer binders, engineered backfill, secondary aggregates, timber grading and reuse, and closed-loop PPE recovery. These are supported by geochemical and mechanical testing, life cycle assessment, QA/QC processes and digital provenance tracking. The study envisages to divert up to 30–40% of spoil and construction waste from landfill and to achieve 15–25% reductions in embodied carbon, mainly through cement substitution and reduced extraction of virgin materials.
The initiative aligns with SDG 12 (Responsible Consumption and Production) and integrates workforce development through microcredentials designed to embed circular practice into vocational and industry training. The findings will guide procurement specifications, policy settings and CRC-aligned industrial strategies that can support local manufacturing capability and reduce disposal pressures.
This paper presents a scalable framework for embedding spoil and construction waste valorisation into major transport projects in Australia and internationally, strengthening the shift toward a more circular and resource-efficient built environment.