Composites have seen increased usage for repair of pipelines. The performance of the entire metalcomposite
system has not been extensively addressed with regard to corrosion of the substrate and
adhesion loss when the conditions are wet and the substrate is cathodically protected. In this work we
have investigated the influence of corrosive environments on the performance of composite repair
systems for pipelines. Earlier in this work we used FEA models to evaluate a composite patch for
pipelines and the present research includes the experimental results for both patch and full-wrap
composite repairs in simulated and field environments. The effect of impacts, cathodic protection, long
term immersion, and soil corrosivity have been investigated by monitoring variables related to potential
and conductivity of the electrolyte. We have also tested mechanical properties via four point bend on
specimens intentionally exposed to ASTM cathodic disbondment tests. We have also evaluated the
performance of these repairs in a modified ASTM G8 cathodic disbondment test with the addition of
high pressure cyclic loading. By monitoring these variables, loss of adhesion and integrity in the
composite-metal system is addressed.
Keywords: Composite repair, cathodic disbondment, nonmetallic repair, carbon fiber, fiberglass,
mechanical testing