Characterization of corrosion morphologies from deteriorated underground cast iron water pipes

Abstract

Following the completion of the Advanced Condition Assessment and Pipe Failure Prediction project in Australia, it has emerged that cast iron pipes normally experience corrosion damages extending over the large spatial area that resemble a patch, and structural failures are commonly associated with these patches. In this study, we defined a corrosion patch as a cluster of individual defects within or less than the one-wall-thickness distance of each other and conducted a morphometric study on patches from several deteriorated cast iron pipes. It was found that the size parameters, viz., the patch length, width, area, and volume potentially attain steady-state progression over long-term deterioration and are consistent with current understanding in underground corrosion. The rectangularity, convex deficiency, and solidity shape parameters were found to be related to each other and could be described by power-law functions. Moreover, the analysis of two-dimensional (D 2D ) and three dimensional (D 3D ) fractal dimension parameters revealed that they serve as useful proxies for different patch properties. In particular, the D 3D revealed linear trends with the patch aspect ratio and an ability to delineate between failed and in-service pipes. It is expected that the results from this study will serve as important baseline information for future works aiming to generate and implement realistic corrosion patches for pipe structural integrity analysis. K E Y W O R D Scast iron, corrosion patch, fractal dimension, long-term corrosion, morphology

Investigation of Soil Physicochemical Effects on the Corrosion of Buried Iron Pipes

“…The work of several scholars shows the identification of soil corrosivity status depends on the specific location and pipe materials suitability where the installation is performed. Corrosion damage of buried water pipe surfaces results from a chemical and electrochemical reaction with a function of time process at soil/pipe interface [6]. The effect of soil on the ferrous metals needs to be studied and predicted the service life before mass production of the items to be buried to create the chance of design modifications.…”

Corrosion Characterization at Surface and Subsurface of Iron-Based Buried Water Pipelines

“…Corrosion damage of water pipes starts from both internal and external surfaces and continues towards the subsurface depending on the exposure time and environmental factors. The formation of external corrosion scales on the surface of buried water pipes is caused by electrochemical reactions between pipe and soil materials [ 13 ]. Characterization of corrosion scales is the best technique to determine surface deterioration and corrosion morphology.…”