Measurement of chloride ion concentration in concrete structures using terahertz time domain spectroscopy (THz-TDS)

摘要

We have employed terahertz time domain spectroscopy (THz-TDS) to investigate the chloride ion (Cl~) concentration in concrete structures. Cement paste and mortar samples with different Cl~ concentrations were prepared and their absorption coefficients were measured in the sub-terahertz frequency range. In both cases, the absorption coefficient increases with the increase in Cl~ concentration and a good linear relationship between them is observed. Our results demonstrate that the THz-TDS could be a valuable tool to monitor and inspect the Cl~- concentration in concrete structures.