|Cooling towers at a thermal power plant in Bishan, China, were built in the mid-Eighties.
The original coal tar epoxy applied to the interior wall of one of the cooling towers had failed after approximately 10 years of service.
In 2000 the original epoxy coating was removed, and another epoxy coating was applied to the interior, but this epoxy delaminated and failed completely, only after 3-4 years in service.
In 2004 the owners selected to use Cem-Kote Flex ST waterproofing for the entire interior, with a total area of 8,000 m2
There were a number of technical reasons for using Cem-Kote Flex ST cementitious flexible waterproofing instead of very low permeability epoxy system, but the main reason was the very poor performance of epoxy systems in these types of applications throughout northern China and elsewhere.
Advantages of Cem-Kote Flex ST over epoxy are its much lower applied cost of the polymer-modified cement versus the epoxy coating and speed and ease of application
The most difficult task was to remove the existing epoxy coating since only some of the epoxy was completely de-bonded and considerable areas of the epoxy remained well adhered. Rotating, mechanical, hand-held grinders were used to remove the epoxy. Due to time and economic constraints well-adhered epoxy was not removed.
Cem-Kote Flex ST was brush applied in two coats to a total thickness of 2 mm (80 mils).
The entire project, , including surface preparation & Cem-Kote Flex ST application, was completed only in 1 month.