Tools to monitor corrosion of cement-containing water mains

Abstract

Approximately 40,000 km of the drinking water network in The Netherlands consists of asbestos cement water pipes. The number of fractures in these pipes has increased greatly in recent years. This is due to corrosion of the asbestos cement (AC) which affects the condition of the pipe. Every time a fracture occurs, the question is raised of whether the pipe in question has to be replaced or repaired. A relatively simple destructive technique and non-destructive tests are used on a large scale to assess the condition of the AC pipes in use. Not only is corrosion detrimental to the pipes themselves, it also influences the water quality. Corrosion of the inner walls of cement-containing pipes involves the leaching of hydroxides. This causes pH changes resulting in scaling in water mains and domestic installations. Monitoring techniques have been developed to determine the effects of leaching on water quality. The large-scale use of the relatively simple techniques at water companies increases insight into the condition of the drinking water network, the life expectancy of the pipes and the effects of corrosion on the water quality. Applying these techniques enables those involved to make decisions on pipe replacement and to provide solutions for reducing the effects of leaching.