One of the advantages of corrugated HDPE and PP pipes over traditional materials such as steel and concrete is their durability in a vast variety of service conditions. Plastics are known to be resistant to abrasion and corrosion; as a result, their service life can often exceed that of competing materials.
For example, the first known cross-highway corrugated HDPE culvert pipe was a 24 in. (600 mm) diameter pipe installed by the Ohio DOT in Noble County in September 1981.
It was chosen due to the aggressive soil conditions (abrasive and acidic mine drainage conditions with pH levels ranging from 2.5 to 4.0.) which were rapidly deteriorating the other traditional culvert materials, causing them to fail within a few years.
The corrugated HDPE pipe is still performing nearly 40 years later with no discernible wear or changes in performance. Another example that demonstrates the durability and strength of corrugated HDPE pipe is the Pennsylvania deep bury study, in which a 24 in. (600 mm) diameter corrugated HDPE pipe was installed in 1987 underneath Interstate I-279 north of Pittsburgh.
The test installation consisted of 576 feet (160 m) of pipe length with a maximum fill height of 100 feet (30.5 m). It has been the subject of numerous studies and evaluations and is still in place
today, demonstrating the capability of the pipe to perform in extreme conditions.
This article will first identify some of the factors that influence the durability of corrugated HDPE and PP pipes and will conclude with procedures for determining the service life of corrugated HDPE pipes manufactured with virgin materials, corrugated HDPE pipes containing recycled content, and corrugated PP pipes.
Factors Influencing Durability
The primary factors that influence the durability of corrugated HDPE and PP pipes include the following: stress cracking (also known as slow crack growth), ultraviolet (UV) radiation, oxidation, chemical attack, abrasion and wear, effects of extreme temperatures, rodent attack, and flammability.
Of these factors, the first three (stress cracking, UV radiation, and oxidation) are the primary factors that govern the service life of corrugated HDPE and PP pipes. The remaining factors may have more intermittent or localized effects on the durability of the pipes, but they do not typically factor into the service life protocols for the overall pipe system. Read Full PDF