Modelling the performance of a corroded pipe section repaired with three-parts epoxy grout and with three-parts epoxy grout plus nanofiller

Abstract

Steel pipelines have been used for the transportation of oil and gas for more than a century. With exposure to the harsh condition of the environment, steel pipelines are subjected to corrosion that deteriorates their function through metal loss. To remedy this, several repair techniques have been developed to extend their service life, particularly, techniques that do not interrupt the flow of the oil and gas. There are three main components in a Fibre-reinforced Polymer (FRP) composite repair which are (1) FRP composite wrap, (2) infill material, and (3) interlayer adhesive. Past research had looked at enhancing the infill material, which is usually an epoxy grout, with the aim to reduce or remove the number of FRP composite wrap layers. One of the ways to enhance the infill material is to add Graphene Nanoplatelets (GNPs) to the epoxy grout. This was proven by carrying out different mechanical tests on a neat three-part epoxy (Infill A) and a three-part epoxy with 0.1% GNPs added by weight (Infill B). With the mechanical properties obtained for both infill materials, the pipe sections were then modelled with a finite element software to determine the repair performance without the use of FRP composite wrap. The difference of failure pressures between the pipe repaired using Infill A and Infill B over the unrepaired pipe were 2.7% and 4.2% respectively. The failure of the repair was due to the debonding of the infill materials from the pipe section. However, this research has provided significant information in understanding the properties of the infill materials as well as the numerical modelling on a repaired pipe section.