MID-INFRARED SPECTRA OF CHLORIDE ION IMMOBILIZED ON CEMENT
Keywords:Mid-infrared spectroscopy,, Infrared spectrum, Bound chloride ions in cement
A strategy based on infrared spectroscopy is prospected to be used as a novel nondestructive inspection method to assess the risk of chloride attack on reinforced concrete (RC) structures. The characteristics of the infrared spectra of bound chloride ions in cement in the mid-infrared region were investigated in this study to examine the concentration of chloride ions on the surface of the concrete using the mid-infrared spectroscopic camera. The reflection FTIR technique was used to measure the infrared spectra of cement paste samples with varying chloride ion concentrations. Furthermore, multivariate statistical methods were applied to the obtained mid-infrared spectra to critically examine the wavelength bands of the peaks with characteristic values reflecting differences in chloride ion concentrations. As a result, if we can develop an instrument that can measure around 7300 nm, the wavelength that reflects the difference in chloride ion concentration maybe around 7300 nm.