Topic: Lower Carbon & Cost in Sprayed Concrete Tunnelling
Date: Thursday, September 18, 2025
Presenter: Ontario TAC Committee
Location: Lone Star Texas Grill (930 Dixon Rd, Toronto, Ontario)
Time: 5:30 p.m. (Registration) 6:00 p.m. (Presentation)
Registration Cost:
- $10 - TAC Members
- $20 - Non-members
- $10 - Government Employees
Presentation Overview:
This presentation offers a perspective on advancing sustainability in sprayed concrete tunnelling. While sprayed concrete is essential for safe and rapid ground support, its production is carbon-intensive due to high cement use, steel reinforcement, diesel-powered machinery, and waste from over-excavation and over-spraying. To address these challenges, a holistic approach is needed, combining material innovation, equipment electrification, and digitalisation.
On the materials side, progress is being made with low- and ultra-low carbon mixes, enabled by cement replacement strategies and chemical accelerators that provide early-age strength. Laboratory-scale spraying systems now allow rapid testing and scale-up of new binder technologies for tunnel applications.
Electrification of tunnelling equipment, particularly battery-electric vehicles, offers more than 95% reductions in CO₂ emissions when powered by renewable energy. These technologies also improve health and safety by removing diesel particulates and heat, while reducing operational costs.
Digital tools, including smart scanning, automated spraying, and digital twins, further enhance efficiency by ensuring accurate profiles, reducing waste, and supporting a future optimising real-time monitoring and operator assistance.
Case studies from Norway, the UK, India, and Australia demonstrates innovative approaches such as spray-applied waterproof membranes and thin lining systems. Ultimately, carbon and cost reduction go hand in hand, making sustainable tunnelling both environmentally and economically viable.
