Application of Ultrasonic Wave Technology to Evaluate the Corrosion Depth of Concrete in Acid Rain Environment

Abstract

Deterioration of concrete exposed to acid rain environment will take a significant effect on the load carrying capacity and durability of the concrete structures. To evaluate the corrosion depth of concrete in acid rain environment, an experimental study was performed with ultrasonic wave technology in the laboratory. In the experiment, sulfate and nitric acid solutions are mixed to simulate the 3 pH levels (pH 3.5, pH 2.5 and pH 1.5) acid rain environments respectively. After being exposed to the simulated acid rain solutions for certain periods, a series of tests (including ultrasonic nondestructive test, Computerized Tomography (CT) test, compressive tests, etc.) were conducted. Damage depth, mass loss, axial compressive strength, and meso-structure of the concrete specimen under different corrosion state were achieved. It was shown that ultrasonic testing is a reliable nondestructive method to measure the damage depth of concrete. A bilinear regression model is proposed to predict the damage depth of concrete, which is in good correlation with testing results from both ultrasonic testing and CT test.