Nondestructive Evaluation of Damaged Concrete due to Freezing and Thawing by Elastic-Wave Method

Abstract

The damage of concrete subjected to freezing and thawing is normally evaluated with the resonance method, which estimates the elastic properties of concrete. This method is one of several nondestructive evaluation (NDE) techniques that use elastic-wave methods. The damage is evaluated based on resonant frequencies, which are related to the dynamic properties of concrete. Because resonance is closely associated with wave motions, the ultrasonic test (UT), which measures the velocity of wave propagation, is also available for NDE of damaged concrete. Another NDE technique using elastic-wave methods that can be applied to evaluate the damage of concrete is acoustic emission (AE) measurement.
These three techniques are investigated and discussed for NDE of damaged concrete due to freezing and thawing. To theoretically clarify the dynamic behaviors of concrete specimens in the tests, numerical analysis of the three-dimensional boundary element method (BEM) were conducted.
No difference between the dynamic modulus of elasticity and the static modulus was found to exist. Compared with UT and AE, the heaviest damage was estimated by the resonance method in the freeze-thaw process. These results have to be carefully taken into account for NDE of damaged concrete.