It has been well known that corrosion is the predominant mechanism for the deterioration of cast iron pipes, leading to the reduction of pipe capacity and ultimately the collapse of the pipes. To develop a cost-effective and risk-informed maintenance or replacement strategy, it is imperative to understand the mechanisms of pipe deterioration and, based on this understanding, to develop a model for the prediction of the deterioration so that it can be used by engineers and asset managers as a tool for asset management of cast iron pipes. To ensure the safety and reliability of cast iron pipes in service, maintenance and targeted replacement for the deteriorated pipes are necessary. The problem can be further complicated by the diversity in production quality in both cast iron material and pipes and the wide range in the diameter and wall thickness of the pipes. Depending on a variety of factors, including the type of cast iron materials, local geology, and operation conditions, cast iron pipes deteriorate at different rate. Buried cast iron pipes age and deteriorate during the service due to various aggressive environments surrounding the pipes. As a result, a large proportion of water transport and distribution pipes were predominantly made of cast iron in the past although they are being phased out by the introduction of new materials. IntroductionĬast iron has been used extensively in many industrial applications, such as water industry, for more than 150 years. The paper concludes that long-term tests on corrosion behaviour of cast iron pipes can help develop models for corrosion-induced deterioration of the pipes for use in predicting the remaining service life of the pipes. It has also been found that the microstructure of cast irons is a key factor that affects the corrosion behaviour of cast iron pipes. It has been found in the paper that localised corrosion is the primary form of corrosion of cast iron water pipes. In this paper, a comprehensive experimental program is presented in which the corrosion behaviour of three exservice pipes was thoroughly examined in three simulated service environments. The present paper intends to fill the gap regarding the long-term corrosion behaviour of cast iron pipes in the absence of historical data. Although many studies have been carried out to determine the corrosion behavior of cast iron, little research has been undertaken to understand how cast iron pipes behave over a longer time scale than hours, days, or weeks.
In order to assess the remaining service life of corroded cast iron pipes, it is imperative to understand the mechanisms of corrosion over a long term and to develop models for pipe deterioration. It is well known that corrosion is the predominant mechanism for the deterioration of cast iron pipes, leading to the reduction of pipe capacity and ultimate collapse of the pipes.
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