Bentonite Waterproof Liner
Bentonite is a popular choice for SuDS liners due to it being a naturally-derived solution that has intrinsic environmental credentials. It also offers cost savings and reduces construction time.
It is a composite product consisting of sodium bentonite clay sandwiched or needle punched between woven and non-woven geotextiles. Once hydrated and confined, it expands to create an impermeable layer.
VOLTEX
CETCO manufactures bentonite waterproofing sheet membranes called Voltex and Voltex DS. They can be used under concrete slabs, shotcrete, and lagging walls. The membrane is installed before the concrete or other wall Bentonite waterproof liner materials are poured. This allows the contractor to waterproof the project even if the walls will not be poured for some time.
The bentonite clay swells when hydrated and forms a strong mechanical bond to concrete. It can also self-seal small cracks caused by ground settlement, concrete shrinkage or seismic action.
Unlike traditional geotextiles that can degrade with the action of water, bentonite sheet membranes are non-degradable. This is important for applications such as foundation walls where the waterproofing must last as long as the structural integrity of the wall.
Voltex is a bentonite geotextile with an added polymer liner. The polymer liner, bonded to the outside of the bentonite, provides very low permeability for water vapor transmission. This combination makes Voltex an excellent choice for waterproofing concrete structures and for use in saline or contaminated conditions.
It is important that the contractor installs VOLTEX under sound, structural grade concrete. The concrete should be free of debris, oil, grease, cement laitance and other foreign matter that can impair the performance of the waterproofing system. The contractor should also ensure that existing and forecasted weather conditions are within the manufacturer’s guidelines for application.
VOLTEX DS is an advanced waterproofing material designed for use under reinforced concrete slabs 100 mm thick or more on a compacted earth/gravel substrate. It is not recommended for use on masonry block foundation walls or split-slab plaza deck construction.
The advanced waterproofing capabilities of VOLTEX DS are further enhanced with the addition of a polymer-treated sodium bentonite, which offers protection in low to moderate saline or contaminated groundwater conditions. The contaminant-resistant bentonite is able to protect the concrete and reduce the impact of chlorides, nitrates, phosphates, lime and organic solvents.
Like the Voltex DS, the VOLTEX CR is a bentonite geotextile membrane with an added polymer liner. The patented polymer liner combines with the bentonite to provide exceptional waterproofing and very low permeability for water vapor transfer. It is an ideal waterproofing membrane for concrete, shotcrete, and saline or contaminated soil conditions.
In this project, Brisk Waterproofing was hired to apply approximately 100,000 sq. ft. of below grade waterproofing to the walls and floor of the MBTA transit tunnel. For the walls, the Fish farm lining geomembrane company used Cetco’s Volclay Ultraseal SP bentonite sheet waterproofing membrane. It was selected for the project due to its ability to withstand the high-pressure from the shotcrete being pumped and not tear or separate along the seams. The project was built adjacent to the Baltimore Convention Center, so the excavation footprint was extremely limited.
As the leading bentonite waterproofing company in the world, Cetco has a wide range of products to meet the needs of projects of all types and sizes. In addition to their popular Volclay Panels, they also offer the bentonite/geotextile product called Voltex DS and Ultraseal CR, which is a bentonite/polyethylene mix.
