The Issue
CK-Tech Ltd was contacted by the joint venture who were delivering the west section of the Thames Tideway Tunnel, to carry out injection work on the tunnel secondary lining in the Frogmore Connection Tunnel constructed as part of their works.
It was reported that several cracks had formed shortly after casting the secondary lining and were deemed as early age shrinkage cracks where the cracks ranged between 0.1- 0.5mm wide. Following the specification, it was a requirement to inject all the cracks above 0.3mm.
The Solution
CK-Tech Ltd successfully injected all of the cracks by injecting Sikadur-52 Injection Normal using a 1-component pump. To eliminate the need for additional drilling into the lining to accommodate steel packers, Desoi surface adhesive packers were installed along the length of the crack using MC-DUR Kleber PU-47 as an adhesive. The remainder of the crack was sealed to allow the build-up of pressure leaving a 20mm vent gap in each crack to monitor if the product was travelling along the crack.
The Result
Following removal of the sealant, the cracks greater than 0.3mm in width all appeared to have been successfully injected and filled with epoxy resin.
