Evaluation of Externally Applied FRP-Concrete Bond Strength Using Non-destructive Testing Methods

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A project at the University of Texas at Arlington aims to develop guidelines to be followed to quantitatively evaluate the FRP-concrete bond strength using non-destructive methods. The proposed concept consists of using the NDE approach to obtain NDE test parameters (such as ultrasonic attenuation, velocity change, thermal dissipation, refraction angle change and amplitude change) from test samples and then to correlate the parameters with the actual bond strengths measured when these same samples are destructively examined. Each sample will include a factor that is supposed to affect the bond strength (such as adhesive type, adhesive thickness, voids, surface preparation, surface roughness, curing, FRP type and age of adhesive). A finite element model using computer software (ABAQUS) for each sample will be constructed to verify the effect of the different factors on the bond strength obtained from the experimental tests.

In order to evaluate the bond strength the following non-destructive techniques will be performed:

Infrared Camera:Two tests will be conducted using the Infrared camera. The first test will measure the rate of heat dissipation and the second test will measure the heat propagation.

Ultra-sonic device:Each sample will be scanned using the ultra-sonic device. The velocity of the sound wave will be recorded corresponding to several distances between the transmitter and the receiver and different angle of rotation of the transmitter.

Ground Penetrating Radar (GPR):Each sample will be scanned and the wave profile, the frequency and the amplitude of the wave will be recorded. The angle of refraction and the reflection of the wave through different materials are different. A comparison between different scans may lead to the identification of the parameters.