In the mine process, wastewater treatment, and sea water desalination industries steel tanks are being replaced by geomembrane-lined concrete basins as a cost-saving measure. Liner seals to concrete structures are made mechanically with stainless steel batten strips or by welding the liner to CPL strips embedded in the concrete. The liners are typically installed as large loose bags with metal batten bar attachments to the concrete around the top, and occasionally at intermediate heights on the wall. Unfortunately, it is difficult, particularly in floor/wall corners, to fully support the liner so it functions as intended solely as an unstressed barrier. Improved performance can be obtained by using a CPL with special corner profiles and welding integrity features. The CPL is held in place on the concrete surface.
Batten bars are often the locations of leaks and require special attention. For instance the intent is not to torque the bolts as much as possible, thereby inducing a quilted profile in the strip, but rather to compress the gaskets under the batten bar uniformly so they do not exceed the elastic deformation limit.
The use of a CPL embedment strip appears to offer a more assured seal than a batten bar. However, it is critical to have the strip fully embedded in the concrete and without any voids that can provide a leakage pathway along the underside/concrete interface. The butt joint ends and chamfered corners of the strip must be welded to avoid leakage. In both cases the CPL and batten strips should not bridge cracks in the concrete and design should ensure there are no 90⁰ corners close to the sealing strips that might cause the liner to be pulled out from under the strip, or for the weld to be sheared.
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