Have you ever been driving over a bridge and wondered who is in charge of making sure it is safe? Or how do they test for rust and corrosion? Or maybe you have some knowledge of corrosion testing methods but are not sure of the best assess it. Maybe you do not know what NDT methods are all about. No matter the circumstances, we are here to help. In this blog, learn the importance of corrosion assessment, how to do it, and the differences between destructive and non-destructive concrete testing (NDT).
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Why Is Corrosion Assessment Important?
ASTM International defines corrosion as “a chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties.” In simple words, they summarize it as, “The deterioration of a metal caused by the reaction of the metal with the environment.” Corrosion is a natural process and is visible in everyday life. You can even see it on a cast iron pan. However, there are many types of corrosion. When large concrete structures with steel rebar begin to corrode it can create serious hazards for the bridges, highways, and buildings we use every day. This type of corrosion can often go unnoticed for a long time, which is one of the reasons regular testing is important. By the time you see corrosion of the rebar coming through a concrete structure, it may be too late to repair.
How to Test Concrete for Corrosion?
There are so many ways to test for corrosion. Some common methods for testing damage and deterioration on rebar include:
- Visual Inspection
- Infrared/Thermal Imaging Inspection
- Coring and chipping
- Ground-Penetrating Radar (GPR)
- Half-cell potential test
Each of these methods has its own pros and cons. Some are destructive methods and others are difficult to implement. For example, the Ground-Penetrating Radar (GPR) technique requires an expert for data interpretation. In addition, some of these methods can be ineffective or inaccurate. In particular, the visual inspection method is only a starting point to determine immediate repair needs. But, it cannot provide a proper assessment.
Destructive vs. Non-Destructive Concrete Testing Methods for Corrosion
As the name suggests, destructive testing – such as coring and chipping – damages the concrete in such a way that it needs repair after testing. The idea is that by breaking off or destroying a piece of concrete, you can easily examine it using a variety of methods. However, this has obvious side effects. If the results reveal that the rate of corrosion is not of concern, you have damaged the structure for no reason.
On the other hand, non-destructive concrete testing methods, such as Infrared/Thermal Imaging Inspection allow engineers to test a concrete structure safely, without damaging it. Overall, these methods allow you to gather results quickly. If the concrete is performing well you can leave it as is. These methods are often simple, and there is no need to worry about performing them too frequently, as your concrete structure will not be negatively affected by using the device. However, it is important to note that some of these methods are more accurate than others.
An Award-Winning NDT Device for Concrete Corrosion Monitoring
If are on the lookout for a non-destructive concrete testing device to monitor corrosion, we highly recommend our iCOR® device. iCOR is a unique, wireless option for NDT corrosion detection in reinforced concrete structures. iCOR uses patented CEPRA technology which allows the device to estimate the corrosion rate of rebar without requiring a physical connection to the rebar (as most other devices do). This makes iCOR the most convenient and only wireless corrosion rate measurement device that may be used in the field or the laboratory. For further details, check out our iCOR FAQ page.
**Editor’s Note: This post was originally published in July 2020 and has been updated for accuracy and comprehensiveness in July 2022.