Influence of Wall Thickness on the Thermo-Mechanical Properties of Aging HDPE Pipes Under Freeze–Thaw Cycles in Quebec Province, Canada

The present study addresses the question of what effect wall thickness would have on the thermo-mechanical properties of corrugated HDPE pipes aging under freeze–thaw cycles in Quebec province, from the surface to its interior. Five commercial corrugated HDPE pipes for transportation infrastructure applications aging within 14 years from different locations in Quebec province (Canada) were examined. The impact of wall thickness (4.50, 7.00, 7.80, 8.90, and 10.40 mm) on decomposition, thermal properties, and long-term modulus of pipes was reported by thermal analysis techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Dynamic Mechanical Analysis (DMA). The antioxidant depletion at the exterior and interior walls of pipes was investigated by oxidation induction time (OIT) measurements. The results indicate that all investigated pipes meet a minimum 20-min OIT requirement where the antioxidant content is sufficient to withstand oxidation. The antioxidants extraction process occurred through the wall thickness which explains the significant difference in the thermal properties of pipes at the exterior and interior walls. However, the change of long-term modulus to variable wall thickness is relatively small.