AbstractThe design service life of 100 years is an essential requirement for modern corrugated high-density polyethylene (HDPE) pipe grades used in road drainage systems. Whether the recycled pipes guarantee performance and can be substituted for virgin pipes is also an issue in the process of being clarified. Furthermore, the variety of area characteristics and the specific serving conditions of the pipes significantly affect pipe service life. Therefore, the University of Sherbrooke and the Quebec Ministry of Transportation (MTQ) recently collaborated to conduct a project on the long-term performance of recycled and virgin HDPE pipes supplied by local manufacturers. This project included investigating stress-crack resistance (SCR) and predicting the service life of new corrugated HDPE pipes fabricated by Canadian manufacturers as well as corrugated HDPE pipes in field service in Quebec under natural aging. Notched specimens were cut directly from the HDPE pipe liner to evaluate their SCR. In addition, four exposure conditions were used: freeze–thaw cycles and exposure to saline, acidic, and alkaline solutions to predict the remaining lifetime of pipes. The SCR was investigated with the Florida test method in water at 3.10 MPa (450 psi) and 80°C, 4.48 MPa (650 psi) and 80°C, and 4.48 MPa and 70°C in compliance with FM 5-573. The data points at elevated temperatures were then shifted to predict the service life of pipes at lower service conditions with the Popelar’s shift method (PSM) and the rate process method (RPM), both of which are extrapolation methods. The results show that, before immersion in different solutions, the recycled could guarantee 100 years of service life as virgin pipes under service conditions of 10°C and 3.45 MPa (500 psi). After immersion, the decrease in SCR was related to the two steps of elevated temperature in the conditioned test and the Florida test, along with the harsh environment of the conditioned test. Moreover, RPM proved better than PSM, because the latter yielded nearly scattered, nonlinear data points.

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