The failure of waterproofing membranes has resulted in considerable damage to concrete structures, hence the proper selection of such a membrane has an important impact on the longevity of a building, says Radcrete Pacific, an Australian supplier of a range of products for the waterproofing and protection of concrete.

“It is not only problems with the concrete itself that can cause the need for repairs to a concrete structure,” says the company’s managing director, Ed Byrne. “The failure of waterproofing membranes on exposed car-park slabs is a common problem, with trafficable surfaces exposed to high-thermal stress conditions.”
The repair of a failed waterproofing membrane – and subsequent possible damage to the concrete surface – can be a laborious and expensive exercise. It can involve removing thousands of square metres of material and then the laying of another membrane, followed by the application of a further protective topping screed.
Radcrete's products were recently used on a 20-year-old car-park slab that necessitated major repairs to the surface of the slab. The car-park is situated in a busy office and shopping complex, which meant that the repairs could only be done at night and on weekends.
“In this case, the owners elected to use an alternative method of repair by removing the existing membrane and then spraying Radcon Formula 7 to the surface of the slab.
“Whereas most membranes are placed on top of the surface, Radcon is a liquid, which penetrates up to 20 mm into the concrete, thus forming a waterproof membrane inside the concrete itself,” explains Byrne.
Radcrete Pacific claims that its product has been repairing cracked concrete for the past 30 years and one of its unique characteristics is that it stays active in the concrete, re-sealing any future hairline cracks upon contact with water.
The owners of the car-park project chose Radcon for several reasons, according to Byrne: “Radcon is fast to apply, so it is able to be done at night and on weekends if that is necessary. It also increases the hardness of the concrete to the same as granite and it does not require a protective screed, so it lowers the overall project cost.”
“Radcon is the preferred treatment for concrete repairs because it seals the cracks all the way through, not just at the top or the bottom like crystal growth and water-repellent products,” he says. “It also accommodates the movement associated with high thermal stress and maintains a passive alkali environment for steel reinforcement protection.”
The contractors used a gas-powered pump unit and a mechanical pump with extended boom sprayer in order to increase application efficiency and consistency in the low light conditions. They completed the application of 3,000 sq m in about four hours.
The product has been used on bridge decks, water-holding vessels and commercial buildings worldwide, including applications such as the Zama city car-park in Japan, which is subjected to constant earthquake activity.
Radcon 7 has been used by several companies on projects in Saudi Arabia and Kuwait. Radcrete has already appointed a distributor in Saudi Arabia, where it is represented by the Jeddah-based Isam Kabbani Group and is currently in discussions with a number of companies in the UAE, Qatar and Kuwait and expects to appoint several distributors in the coming months. It later hopes to break into the Bahrain and Oman markets.