Internal Pressure Capacity and Bending Behavior of Glass Fiber Reinforced Composite Overwrapping PVC Plastic Pipes.

Abstract

The challenge associated with the use of polyvinyl chloride (PVC) plastic pipelines is to improve their structural integrity without increasing their cost. Currently, PVC pipelines are the most cost-effective method of transporting water and sewage drainage. However, the limitations of installed PVC pipelines are well known, including their low deterioration properties (which degrade their load carrying capacity), and their low fracture toughness (which causes catastrophic failure). Both poor deterioration and mechanical properties cause significant losses and sacrifice the structural integrity of pipelines. Many types of deterioration can affect PVC pipelines, including their durability and resistance to environmental effects. Meeting the increased demand for PVC pipelines, cost-effective solutions are necessary to improve their structural integrity. Therefore, this study proposes a glass fiber-reinforced polymer (GFRP) overwrapped system to strengthen the external surface of PVC pipes, which will improve pipes pressure and flexural capacities. Accordingly, an extensive experimental program (including five phases) is developed and performed to examine the performance of GFRP composite overwrapped onto PVC plastic pipes. These phases include the fabrication process and different types of tests for evaluating the structural integrity of the GFRP/PVC pipes. The results showed that the proposed overwrapped system significantly improved the flexural carrying capability. The initial flexural failure load increased significantly, with an improvement from 64 to 1140 N. In addition, the ultimate flexural load was improved by a factor of nine. It was also found that the pressure capacity and the flexural behavior were significantly affected by changes in the fiber orientation angle. It should also be noted that as the pipe diameter increased, the pressure capacity decreased. However, as the pipe diameter increased, the flexural carrying load capacity increased. It is also important to note that the main identified failure modes for GFRP/PVC pipes were dominated by matrix cracking, fiber debonding, and fiber breakage. For the internally pressurized GFRP/PVC pipes, the failure mode was mainly dominated by fiber breakage and fiber pullout.