NCHRP Report 870, Field Performance of Corrugated Pipe Manufactured with Recycled Polyethylene Content, was recently published by the National Academy of Sciences. NCHRP Report 870 summarizes the research conducted in NCHRP Project 4-39, a 3-yr. $600,000 research project awarded to TRI-Environmental and Crossroads Engineering Services. Dr. Pluimer of Crossroads Engineering Services served as co-Principal Investigator of the study and primary author of the report. Other key authors and contributors included Joel Sprague, PE, Jay Sprague, Mario Paredes, Sam Allen and Rick Thomas from TRI-Environmental (Rick was also the PI and primary author of NCHRP Report 696, the predecessor to this research project); Dr. Leslie McCarthy, Dr. Andrea Welker, Dr. Eric Musselman and Jeffrey Cook of Villanova University; Dr. Shad Sargand and Ehab Shaheen of Ohio University; and Kevin White, PE, of E.L. Robinson Engineering.
The report summarizes groundbreaking research that included the development of multiple new ASTM and AASHTO specifications and test methods for pipes manufactured with recycled materials. The research resulted in the incorporation of post-consumer and post-industrial recycled materials into AASHTO M 294, the primary specification for large-diameter corrugated high density polyethylene (HDPE) pipes used for highway culvert and storm drainage applications, allowing states the option to choose and specify a more sustainable and resilient pipe for these critical components of our transportation infrastructure. Pipes manufactured with recycled materials in accordance with the new AASHTO M 294-18 specification were shown to have a service life in excess of 100 years.
A key component of this research was the development of a new test method, the Un-notched Constant Ligament Stress (UCLS) test, published as ASTM F3181-16. The UCLS test is a simple short-term tensile test conducted on test specimens taken directly from the pipe wall and compression-molded into a plaque. When conducted at several different elevated temperature and stress conditions, the relatively short-term test can be used to predict the long-term performance of pipes in various service conditions. Dr. Pluimer and his research team developed a service life prediction model that predicts how long these pipes will last in the field based on their performance in the UCLS test. The service life prediction model was validated on multiple full-scale pipes in both the field and the laboratory. The result was the development of a true performance-based specification (incorporated into AASHTO M 294-18) for corrugated HDPE pipes manufactured with recycled materials, a first for the pipe industry. The test requirements in the new AASHTO M 294-18 specification are designed to ensure that corrugated HDPE pipes manufactured with recycled materials will last in excess of 100 years in highway culvert and storm drainage applications.