Plastic Pipes Conference Association # 2004 Milan
In past ten years, there is a significant growth in the use of high density polyethylene (HDPE) corrugated pipes in transportation related applications in the United States. At the same time, the evaluation of stress crack resistance (SCR) of the HDPE corrugated pipes has also gone through many changes. A comprehensive SCR specification on pipe resins has been established recently; while no changes have been proposed for the finished pipes. The current SCR test on the corrugated pipe is impractical and ineffective. In this paper, the SCR of finished pipe was evaluated using the notched constant tensile load (NCTL) test. Five pipes with diameters from 460 to 900mm were tested together with their corresponding pure resins. The effects of pipe processing were investigated by testing specimens taken directly from the pipe liner and pipe crown locations at two different orientations. A large difference in the SCR was measured between the two locations. Furthermore, the SCR were affected by the orientation of the specimens and the notching position due to bending stress, residual stress and orientation of polymer chains. In all of the test configurations, the liner specimen oriented along the longitudinal direction of the pipe with an outer surface notch yielded the shortest failure time. The pipe processing decreased the SCR of the corresponding resin. The reduction factor varies from pipe to pipe ranging from 0.29 to 0.86.
Author(s) : Hsuan, Zhang, Wong
The 100-year stress crack resistance (SCR) of corrugated HDPE pipes was evaluated using a 600 mm diameter pipe. The SCR tests were performed on the finished pipe at the liner and junction locations. The notched constant ligament stress (NCLS) test (ASTM 2163) was used for the pipe liner assessment. For the pipe...
Author(s) : McGrath
Gravity flow thermoplastic pipes use profile wall geometries to provide maximum wall stiffness with minimum wall area. This practice minimizes the material used in manufacture, and thus the product cost. In the case of some thermoplastic pipe, polyethylene in particular, this practice has led to a need for design...
Author(s) : Beaver, McGrath, Scharff
Plastic pipe has been used for many years in applications to control surface water runoff by detention, retention, and infiltration. Review of deficiencies with available pipe geometries resulted in creation of a new ‘pipe’ product, termed chambers. Stormwater chambers are arch-shaped, open bottom, polypropylene...