Asbestos encapsulation between precast segments.
The newest of the two road tunnels running beneath the River Mersey, the 2.2 kilometre long Kingsway dates from the early 1970’s.
The tunnel bore is lined by precast concrete segments and the joints were sealed with a caulking material found to contain asbestos. With the passage of time, water ingress and general contamination and had conspired to undermine the integrity, causing breakdown within the joint and the release of potentially harmful asbestos fibres into the invert which is the main source of ventilation. An asbestos encapsulation system was needed which would be both effective and safe to use in the working environment.
Working under strict safety conditions, the joints were raked out and reinstated with Fastfill. Two coats of Cemprotec E942, reinforced with Cemprotec Scrim were then applied to seal the joint and encapsulate any residual asbestos fibres. The non-hazardous nature of both products was a crucial factor in the material selection process – Fastfill and Cemprotec E942 are water-based, yet they can be applied to a damp substrate, forming a waterproof seal which is resistant to 10 bar.