The root cause of water pipeline failures stems from the cracking of external concrete. When this outer layer of concrete cracks, it allows water to seep through, initiating the corrosion of the prestressing steel wires wrapped around the inner steel pipeline. These wires are critical, as they maintain the pressure balance within the pipeline. As the steel wires corrode and eventually break, and the pressure exerted by the fluid inside the pipeline overwhelms the weakened structure. This catastrophic chain reaction of uncontrollable events leads to the serious pipeline leaks.
During a conversation with Jeff Bishop, the Quality Assurance Manager at Suncor Energy Services Inc., he emphasized that the most significant challenge facing the pipeline industry today is external concrete cracking. This issue is pervasive, affecting both water and energy pipeline systems, with cracking setting off a chain of events that ultimately leads to pipeline failure.
Currently, one of the mains solutions employed by the pipeline industry to reduce the likelihood of concrete cracking is the use of rebars (reinforcement bars) inserted into the concrete, much like how nails are hammered into a piece of material. There are many types of rebars that the industry uses.
The idea behind using rebars is to strengthen the structural integrity of the concrete, ensuring it remains durable in harsh environmental conditions, which would otherwise lead to cracking over time.
However, this approach has its own limitations. While rebars improve the concrete’s tensile strength and resistance to corrosion, they do not address the ROOT cause of cracking, such as environmental stresses like temperature fluctuations, ground movement, or the natural degradation of both concrete and steel.
Cathodic protection is an electrochemical technique that is used to prevent metal surfaces from corroding by converting them into the cathode of an electrochemical cell. We’ll summarize the two main types of cathode protection: