Evaluation of the Stress Crack Resistance of Corrugated High Density Polyethylene Drainage Pipes

As the use of corrugated high density polyethylene (HDPE) pipes increases in transportation applications, the requirements on their long-term properties pipes becomes more rigorous. Recently, the Florida Department of Transportation required all drainage pipes in critical applications to have a design life of 100 years. Thus, a research project was initiated to assess the long-term properties of corrugated HDPE pipes. This paper presents the stress crack resistance (SCR) part of the project. The evaluation of SCR in this study is focused on the finished pipe and not the HDPE resins that are the focus of the AASHTO M 294 specification. As a result, manufacturing stresses are included in the results. SCR tests were developed to replicate pipe locations that have shown cracking in the field. Results from the preliminary test confirmed that the junction and longitudinal profiles of the corrugated HDPE pipes are most susceptible to stress cracking. An interim specification is established using an incubation environment of 80°C in water under an applied stress of 1.72 mPa (250 psi) for a minimum duration of 155 days. The testing protocol for the full specification is on-going to confirm and refine the extrapolation methods.