Integral crystalline waterproofing for concrete tanks

November 8, 2004 In the News

Asian Water – Volume 20, No. 9 – November 2004

Used for more than 30 years worldwide, Integral Crystalline Waterproofing (ICW) is an innovative technology that uses a chemical reaction to turn concrete into a permanent waterproof barrier. Read on to find out how ICW offers a superior waterproofing and self-sealing properties.

The Seletar Water Reclamation plant is part of a network of Singapore water treatment plants. These facilities are key components in Singapore’s plan to become selfsufficient in water production and reduce the amount of water it imports.

Nearly 250,000 m3 of wastewater from Singapore’s sewers is processed daily through the plant, which uses reverse osmosis technology to produce water that can be used by industry in place of valuable potable water. Water generated at the Seletar plant is added to Singapore’s sewers, where, once processed through conventional water treatment facilities, it can be used as drinking water.

Recently, the Seletar Water Reclamation facility added a new post-tension water tank and needed to select an appropriate waterproofing system for the structure. In post-tension construction, steel strands are threaded through plastic tubing that runs in both directions through a concrete slab. The steel strands are then tensioned at either end of the concrete, enabling it to bear more weight, and reducing cracking. While post-tension construction offers a number of benefits, it requires reliable waterproofing protection to safeguard the steel cables from corrosion and deterioration.

In addition to providing superior corrosion protection, the waterproofing system selected for the Seletar project needed to meet several other key criteria. It needed to provide for quick and efficient installation, in order to meet the 30-hour timeline provided for the tank to be poured and set. And, since the recycled water stored in the new structure would potentially enter the country’s water supply, the waterproofing system needed to be guaranteed non-toxic.

With a wide range of waterproofing systems available on the market today, the project team had many choices, including:

• Self-adhering, rubberised asphalt sheet membranes or barriers.
• Liquid membranes that are applied by spray, roller or trowel.
• Cementitious products that are mixed with water and brush-applied.
• Built up systems, where layers of hot asphalt are alternated with perforated felt layers to form a physical barrier.
• Sodium bentonite, a clay material that is applied in panels to the outside of a structure and works by absorbing water and swelling to fill the cracks and voids in concrete.
• Integral crystalline waterproofing (ICW) systems, which create a chemical reaction within concrete that causes crystals to form and grow, filling the spaces between concrete particles and permanently blocking water.
• Integral crystalline waterproofing (ICW) systems, which create a chemical reaction within concrete that causes crystals to form and grow, filling the spaces between concrete particles and permanently blocking water.
• After weighing the various options, the Seletar plant team selected an integral crystalline waterproofing system because it offered a number of key advantages over the other alternatives.

Read more about:

• What is Integral Crystalline Waterproofing (ICW)?
• How does ICW work?
• Benefits of using ICW
• How is ICW applied?
• Is ICW right for your concrete water containment structure?
• Can ICW be used in existing concrete water containment facilities?