Abstract

In recent years, using concrete to absorb CO2 in the atmosphere has attracted attention as one of the global warming countermeasures. In general, destructive methods have been used to evaluate the amount of CO2 absorption in concrete buildings and civil engineering structures. However, it needs to sample a portion of the concrete, and it is impractical to conduct continuous disruptive sampling of the structures in use. Therefore, it is necessary to develop non-destructive tests to evaluate the amount of CO2 absorption in concrete. In this study, Multi-spectral imaging, which are the methods of non-destructive tests, were used to visualize the presence of calcium carbonate with depth-axis from surface of the concrete specimen which have been the preliminary drilled holes. In addition, moistened cotton swabs were used to extract the pore solution by pressing the inner wall of the hole and to test it for determination of the distribution of pH with depth. The results indicate that Multi-spectral imaging can evaluate different carbonation depths of concrete samples. Moreover, PH of each point examined in the specimens can evaluate as the depth distribution of calcium carbonate. Results were compared and discussed with each other depending on each methodological characteristic.