A New and Improved Way to Detect Corrosion in Reinforced Concrete

Giatec's iCOR™ device is a compact and comprehensive non-destructive testing (NDT) tool for detailed corrosion evaluation of reinforced concrete structures. It is unique in its ability to perform three-in-one measurement of the rebar corrosion rate, the half-cell corrosion potential, and in-situ electrical resistivity of concrete without the need to drill a hole to connect to the rebar directly.

These measurements are critical to the success of rehabilitation projects or to the repair of concrete structures. Getting all three measurements with one device is not only a huge time saver, but it also reduces the overall cost and resources needed in the condition assessment of concrete structures.

This is my first experience performing corrosion detection and I am very happy with iCOR™. All the results obtained from iCOR™ have shown consistent results compared with other non-destructive testing methods. The application is very user-friendly, providing me very clear and useful information on-site, which allows me to perform time effective measurements.

– Milad Moghaddas, QuakeWrap Inc., United States

This wireless technology is able to perform directional rebar corrosion measurement in both X and Y axis independently. As such, it communicates the results wirelessly to a custom Android application, which then processes the information and outputs the results in a very user-friendly interface. iCOR generates real-time corrosion contour maps, which you can then save as a PDF report or CSV file and share with everyone on your team via email or Dropbox.

Because of this, iCOR is in high demand in countries like Japan where wireless technologies ensure that critical structures (e.g. nuclear facilities) do not get damaged during the performance of these measurements.

Corrosion Detection in Reinforced Concrete

The Science Behind iCOR

iCOR measures the electrical response of the rebar inside the concrete using four probes placed on the surface of the concrete. The patented Connectionless Electrical Pulse Response Analysis (CEPRA) technology used to measure electrical resistivity and corrosion rate does not require a connection to the rebar, making iCOR the first product of its kind.

The technique is based on the different voltage responses that the corroded and non-corroded rebar have at low frequency impendence. Note that electrical impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied. In other words, it is the complex ratio of the voltage to the current in an alternating current (AC) circuit.

The iCOR method consists of applying narrow DC/AC pulse currents through two outside electrodes and subsequently measuring the voltage response through the two outside electrodes. Note that the voltage response of a corroding rebar is different from that of a non-corroding rebar.

The voltage of a non-corroding rebar increases in the low frequency zone of the plot but is almost invariable for a corroding rebar.

This concept has been utilized in iCOR technology to detect the corroding areas of reinforced concrete structures from the surface of concrete. By using the input current, the recorded voltage value and a very complex algorithm, the iCOR device is able to calculate the state of corrosion in the reinforcement.

How It Works

Non-Destructive Corrosion Detection in Concrete - iCOR

iCOR is an easy-to-use NDT tool for detecting corrosion in reinforced concrete

Here's how iCOR works from a user standpoint:

  1. Define a grid on the reinforced concrete structure.
  2. Create a grid on the Android iCOR™ app and input information about the rebar size and cover thickness.
  3. To take measurements, press on the point for which you want to perform the measurement and press Run. The device takes only 3 to 10 seconds to output the result.

Research and Statistics

To date, there is no standard in place for corrosion rate measurement. The only standard that is available for corrosion detection is for the Half-Cell Potential test (ASTM C876). This being said, Giatec is currently collaborating with various university research groups in order to compare iCOR results with the real mass loss testing, which will hopefully lead to the creation of a new standard for corrosion rate measurement.

Other researchers in the field have shown iCOR's superior spatial accuracy when compared to various devices and measurement techniques on the market today. Unlike other NDT technologies, iCOR's results were not affected by a very closely spaced reinforcement. The device has thus proven to be very efficient in localizing low/passive corrosion in reinforced structures.

Moreover, iCOR does not polarize the reinforcement that it is analysing so you are able to perform multiple measurements over the same point one right after the other. With other techniques, on the other hand, you have to wait hours before being able to take a new reading over the same location.

Why Choose iCOR for Concrete Corrosion Detection

Still not convinced of iCOR's superiority over other devices on the market? Let's review all the reasons why you should choose iCOR for your corrosion detection and concrete condition assessment needs.

1. No connection to the rebar required.

Unlike any other device available, iCOR does not require a connection to the reinforcement, making it one of the most convenient corrosion rate measurement devices in the field as well as an innovative research tool in laboratory studies.

2. Wireless, non-destructive technology

The iCOR device sends data straight to your tablet, where it can then be stored, analyzed, and shared visualized.

3. Fast and easy to use

Making the switch to iCOR is fast and easy. Minimal training is required.

4. User-friendly app

The iCOR Android app that comes pre-installed on the tablet is a powerful post-processing tool and an easy way to share results with other members of your team. All data is saved on the app for reviewing and sharing at any time.

5. Time savings and cost reduction

iCOR can significantly save time, human resources, and costs in the condition assessment of concrete structures. Furthermore, since iCOR™ is an application-based device, any improvements or upgrades can be easily implemented through the upgrade of the application itself.

6. Comprehensive condition assessment of concrete

This unique NDT device allows engineers to have a comprehensive understanding of concrete quality and corrosion activity, helping them make timely decisions regarding the rehabilitation of and required repairs for concrete structures.

Try iCOR out today! Full details about iCOR available here.

Authors note: A special thanks goes out to Western Exteriors Magazine for publishing this guest editorial in their February 2017 edition