Sikaplan® - Waterproofing Membranes

To avoid the cost of producing and installing custom made formworks for concrete lining at tunnel widenings, shotcrete can be used instead. In this method sprayed concrete is applied directly onto the polymer waterproofing membranes.

To minimize shotcrete rebound, fine wire meshes are laid over the installed polymer waterproofing membranes and fixed with special anchors.

The polymer waterproofing membranes themselves are fixed to a sealing carrier layer made of sprayed concrete. This sealing carrier layer has to level the rough and uneven substrate surfaces in order to enable the waterproofing membranes to be laid without creases and tight to the substrate. There are some important technical requirements for the sealing carrier layer: free from protrusions (no steel fibers), maximum aggregate size ≤ 8 mm, compressive  strength class C25/30 and minimum layer thickness ≥ 50 mm.

FlexoDrain W and Sika® Shot-3

FlexoDrain W half sections are primarily designed for use in tunnelling works where they collect and drain water from the rock. In combination with other drainage components such as branch pipes and collectors, a water drainage system of any size can be formed behind the internal surface and finish of the tunnel shell itself. The FlexoDrain W sections are fixed to the substrate with steel-bolts and the area can also be easily lined with the shotcrete layer.

Lower levels of water intrusion can be sealed using Sika® Shot-3. Sika® Shot-3 is a ready-mixed mortar with an extremely high early strength. This special pre-bagged waterproofing gunite mortar is applied by the dry spray process.

FlexoDrain W sections can also be fixed directly to the rock with sprayed Sika® Shot-3 mortar.