Swellseal Ultra, a Bentonite-based Membrane for Use in Seawater Applications by Neoferma

SwellSeal ULTRA® was developed by Neoferma in order to satisfy the demand for a product that would function well under conditions of seawater contamination. As a result, the design characteristics for SwellSeal ULTRA® were for a product that, when exposed to pure sea water, would have a stable and long-lasting very low permeability to water movement.

Figure 1

The capabilities of the SwellSeal ULTRA® bentonite mix have been demonstrated in extremely rigorous testing by independent engineering studies, such as those conducted by Mueser Rutledge Engineers of New York City, which qualified the bentonite mix for use on the Allied Signal Baltimore Works EPA Superfund Site project adjacent to the harbour in Baltimore, Maryland, which was required by the U.S. EPA to permanently contain the toxic and hazardous materials that had permeated the soil and groundwater at the site over its 200 years of industrial use. The bentonite component of SwellSeal ULTRA® was specified as being the only product that could be used for the permanent backfill that would enclose and contain the site.

Why use SwellSeal Bentonite Membranes*?

Independent surveys have found that using a Bentonite Membrane System in place of traditional waterproofing has significant advantages both in the speed of application and the beneficial effect on the construction programme, as well as savings in the overall cost of the waterproofing element.

Does it work?

Figure 2 illustrates the free swell characteristics of SwellSeal ULTRA® and several other bentonite products when measured in pure seawater. These results show that, while SwellSeal ULTRA® has a swelling capacity equal to or slightly higher than other bentonite products in fresh water, it has about twice the swelling capability of other bentonite products in seawater, including other supposedly salt-resistant products.

A better measure of the sealing capability of a bentonite product is through the measurement of its permeability (hydraulic conductivity) under controlled laboratory conditions. Permeability testing of a demonstration sample of a SwellSeal ULTRA® GCL (6.4mm thick layer of SwellSeal ULTRA® between layers of non-woven and woven geosynthetic fabric) together with samples of GCL products advertised as being seawater resistant was conducted by Geo- Syntech Laboratories of Alpharetta, Georgia, USA.

SwellSeal ULTRA® GCL yielded a permeability value

• 29 x lower than Commercial Salt Resistant Bentonite GCL 1 product,
• 532 x lower than the Commercial Salt Resistant Bentonite GCL 2 product,
• 61,290 x lower than the Contaminant Salt Resistant Bentonite product.

*The size of a roll of Ultra is: 7 .5 x 1.5 m, 4000 gms Mass of Bentonite per m2. Contact Neoferma today and find out how we can assist you: 1300 88 53 70 or neoferma.com

Contact Neoferma today and find out how we can assist you: 1300 88 53 70 or neoferma.com