Expansion Joint Sealing Products from Bayset

Hydro Tasmania - Fisher Flume

Products:
SCUBAPOX 1715 Brushable Heavy-duty Coating
SCUBAPOX 5335 Flexible Underwater Sealant
SCUBAPOX 9120 Polymat Patch Repair Material

The Problem
In typically inclement, fluctuating weather conditions that can see a mild 27°C day followed by a wet 4°C day, Hydro Tasmania was seeking a highly tolerant product to seal the expansion joints in 2,700 lineal metres of their Fisher flume. The flume is an integral part of the overall hydroelectricity scheme as it helps channel the large volumes of water required to generate the electricity. Because of its crucial role, shutdown had to be minimised and repair work performed with a product that wouldn't be affected by the characteristically temperamental weather. Also, the fluctuating temperatures meant the product had to be flexible and remain flexible in all conditions, including extreme cold.

The Solution
With the application requiring a field-friendly, tolerant and flexible product in all conditions, NMP proposed a tailored system centred around SCUBAPOX 5335. The process started with a water blast of the concrete joints to basically clean the surface. Establishing a profile was not a priority in this particular instance as the concrete had a very rough texture, chiseled out over time by exposure to water currents. In fact, the high profile of the concrete forced a slight adjustment to the original plans with applicators using a sand-filled SCUBAPOX 1715 mortar to re-level and prime the surface, ready for SCUBAPOX 5335 to applied over the top. Once the mortar had been trowelled into place, the joint system was prepared. To achieve a thorough seal, good flexibility and for maximum wear characteristics, SCUBAPOX 5335 was used in combination with a polymer repair material, SCUBAPOX 9120.

This particular product consists of strong, smooth, waterproof polymer sheet with a tightly woven fibre backing - ideal for applications requiring tenacious adhesion and overall toughness. SCUBAPOX 5335 was liberally applied to the fibre backing (approximately 2 Litres/square metre), fully wetting out all the fibres before the strip was placed and rolled over the joint to complete the seal.

Notes/Comments
The composite joint material formed a tough, wear-resistant, waterproof seal with the required flexibility to handle the natural movement of the concrete structure. The field-friendly, all-weather products enabled the work to be completed on schedule, saving Hydro the large costs associated with waiting for "just right" conditions needed by other systems.