Feasibility of Application for the SHG Technology of Longitudinal Wave in Quantitatively Evaluating Carbonated Concrete

The ultrasonic transmission detection method is used to investigate the applicability for second-harmonic generation (SHG) technology of longitudinal wave quantitatively assess carbonated concrete. principal this use piezoelectric lead zirconate titanate (PZT) patch detect waves during concrete carbonation process and extract non-linear parameters from observed signals. Non-linear concretes with two water–cement ratios (CI (w/c=0.47), CII (w/c=0.53)), moisture contents 0%, CI-W 100%), three incident frequencies (50 kHz, 75 100 kHz) were measured in study. Results experiment demonstrate that high (75 exhibit a better resolution regarding changes microstructure. Moisture 100%) has little effect on rate (CI: 62.73%, CI-W: 60.25, depth: 15 mm) change relative same depth (w/c=0.53)) can be well reflected by parameters. Furthermore, there exists good fit between process. feasibility quantitative assessment carbonation.