Michael Pluimer, Leslie McCarthy, Andrea Welker, Eric Musselman
Papers # 2016 Berlin
A pilot study was conducted with the Southeastern Pennsylvania Transit Authority to evaluate the performance of corrugated HDPE pipes manufactured with post-consumer recycled materials in their railroad applications. Two corrugated HDPE pipes – one manufactured with 100% virgin materials and one manufactured with 49% post-consumer recycled content – were installed underneath a main commuter rail line in October 2013 with just two feet of cover from the top of the pipe to the bottom of the rail. After nearly 3 years of service, both pipes are performing as designed, and no noticeable differences were observed between the two pipes with regards to service life relative to fatigue and stress cracking based on an accelerated laboratory study.
Corrugated high-density polyethylene (HDPE) pipes are an attractive product for culvert and drainage applications in the railroad industry due to their resistance to corrosion and abrasion, long service life, and flexibility. Railroad specifications currently require these pipes to be manufactured with 100% virgin materials. However, due to the push for more sustainable and cost-effective engineering materials and practices, the railroad industry has expressed interest in using pipes made with recycled content provided their long-term performance is equivalent to pipes made with virgin materials.
To evaluate the performance of corrugated HDPE pipes made with recycled content in rail applications, a pilot study was conducted with the Southeastern Pennsylvania Transit Authority (SEPTA). The study was funded cooperatively by SEPTA and the National Cooperative Highway Research Program (NCHRP) Project 4-39. Two 30-inch diameter corrugated HDPE pipes, one manufactured with 100% virgin materials and one manufactured with post-consumer recycled content, were installed underneath a regional commuter rail line in northeast Philadelphia with 0.6 m (2 ft.) of cover from the top of the pipe to the bottom of the railroad tie. The pipes were instrumented with strain gages and extensometers to monitor their performance over time, and a laboratory study was developed to assess the long-term durability of these pipes with regards to cyclical live loads.
The introduction to this study was presented at Plastics Pipes XVII. The study is now complete, and final data are presented in this paper. The pipes have been in service for over 3 years and are performing as designed, with no change in performance since the date of installation. This was a groundbreaking study as it included the first corrugated HDPE pipe manufactured with post-consumer recycled content installed underneath one of SEPTA’s regional commuter lines. The research project was a key component of SEPTA’s ongoing sustainability initiatives.