New lifetime prediction techniques for buried polymer pipes

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Polymer (i.e. plastic) pipes are vital components of Canada's municipal buried infrastructure for stormwater and drinking water applications. Design of these buried structures requires consideration of both the soil and the polymer structure, as well as the soil-structure interactions that develop between the two. But, just how long will they last? Currently, no one can say with certainty. Polymer materials are used with the expectation that they will last at least 75 years', often based on limited data obtained under idealized conditions or educated guesses. While a reasonable first step, Canadian municipal engineers and city planners need more. Whether a polymer water pipe will last 75 or 150 years has billion-dollar ramifications for our ageing and growing urban centres. The overarching vision of this Discovery research program is therefore to create new fundamental engineering science knowledge, train 15 highly qualified personnel, and develop rational predictive techniques all to evaluate how long the polymer components of Canada's municipal buried infrastructure will last. For the first time, long-term soil-structure interactions will be simulated using full-scale physical experiments at elevated temperature, conducted on actual structures in their buried configurations, and where polymer degradation has been accelerated. This highly-original approach will allow us to remove the speculation and finally identify the failure mechanism, the time it occurs, factors affecting it, and what can be done to prolong lifetime. This would be a groundbreaking advancement in how Canadian municipalities, and cities world-wide, manage our vast and ageing sewer and water pipe networks. Knowing how pipes can fail and having tools to predict how long a new pipe will last, or the remaining life of an existing pipe, are essential inputs to management plans that engineers use to increase longevity of these public assets and optimize investments in repair and replacement. The new lifetime prediction techniques will also be used by manufacturers and engineers to investigate specific classes of buried structures. Equipped with new understanding of the underlying mechanisms controlling service life, geometry refinements or materials improvements can be developed to extend the service life of newly built infrastructure. Manufacturers and users will, for the first time, have rational estimates of service lives, replacing index values and judgement'. This will allow utilities to choose products more wisely, and Canadian manufacturers to develop and market products internationally more effectively. This Discovery research program will also provide exceptional training opportunities for 15 highly-qualified personnel (5 PhD, 5 MASc, 5 BASc) with buried infrastructure expertise that is in very high demand by geotechnical and civil engineering consultants.