Non-Destructive and Quantitative Evaluation of Rebar Corrosion by a Vibro-Doppler Radar Method

Abstract

It is well known that evaluation of rebar corrosion is important for the maintenance of reinforced concrete structures, but, it is difficult to simply, quickly and quantitatively evaluate the amount of corrosion of rebars embedded in concrete by conventional non-destructive evaluation (NDE) methods such as electrical, electromagnetic and mechanical method. This paper proposes a vibro-Doppler radar (VDR) measurement method to quantitatively evaluate rebar corrosion by measuring the vibration ability of the rebar forcibly vibrated in concrete by an excitation coil. It is experimentally demonstrated in RC test pieces that the rebar vibration displacement obtained by developed VDR method is valid and is less affected by the moisture in the concrete. In addition, simultaneous monitoring of the rebar vibration displacement of the test pieces is performed through an electrolytic corrosion test and the measured vibration displacement is compared to the rebar corrosion loss evaluated. As the results, it is cleared that the rebar vibration displacement starts to increase from slightly before the occurrences of corrosion crack on the concrete surface as the corrosion loss increases. It is also shown that the rebar vibration displacement becomes 4 times higher than that in initial condition at the rebar corrosion loss of 250 mg/cm2. This implies that the VDR has potential to nondestructively and quantitatively evaluate rebar corrosion in concrete.

Impact of Magnetization on the Evaluation of Reinforced Concrete Structures Using DC Magnetic Methods

“…Only methods that use an electromagnetic and mechanical wave can be effectively used for direct reinforcement assessment. The following methods can be distinguished in the mechanical group: high-frequency, active ultrasonic testing methods [ 3 , 4 , 5 ]; low-frequency-active mechanical methods [ 3 , 6 ], and passive-acoustic emission (AE) [ 7 ].…”

“…Results can be really accurate and relatively easy to interpret. Lower excitation frequencies may be used in some versions of the magnetic flux leakage (MFL) and the magnetic force induced vibration evaluation MFIVE method [ 3 ] or in the method similar to MFIVE described in [ 6 ]. Both of these methods use low-frequency magnetic waves to induce rebar vibration.…”

Magnetic Particle Inspection Optimization Solution within the Frame of NDT 4.0

“…As digitalization evolves from year to year, many processes or industries are unable to cope with this progress [1,2]. Technological processes precede the progress of digitalization, and thus Industry 4.0 was later developed, which also led to the development of processes such as NDT, where we can now see a lot of digitalization, improvements and optimizations in terms of Industry 4.0 [2][3][4]. Despite this, the development of Industry 4.0 comes with changes in terms of the user-equipment interface, and any change involves the unknown, which can bring about reluctance or lack of confidence in the user in the displayed result.…”

“…It aims at an improvement and optimization in this generation of both repair processes and overhauls and the maintenance throughout the life of the equipment. Another need for the development of the NDT 4.0 industry is the cause of depletion of natural resources and environmental pollution; here, we refer to the sustainable development of NDT processes that develops digitalization while also eliminating human error [1][2][3][4]. Sustainability is the field that in recent year has attracted the most attention in production research from various industries and is an important factor not only in technological development but also in the innovation of sustainable systems.…”

Sensing Advancement and Health Monitoring of Transport Structures

“…Miwa [10] proposes a vibro-Doppler radar (VDR) measurement method to quantitatively evaluate rebar corrosion in reinforced concrete specimens. The author provides measurements of the rebar vibration ability forcibly vibrated in concrete by an excitation coil.…”