Comparison of detection methods for carbonation depth of concrete

This paper presents comprehensive research of the advantages and applicability of various concrete carbonation detection methods. Employing a combination of Phenolphthalein indicator (PI), Thermogravimetric analysis (TGA), X-ray phase analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and Quantitative calcium carbonate analysis (CA), a detailed comparison to determine the carbonation depth in the partial carbonation zone of concrete specimens is conducted. Among the quantitative analysis methods, CA measures CaCO₃ content based on chemical reactions, while TGA obtains the concentration distribution of Ca(OH)₂ and CaCO₃. Among qualitative analysis methods, XRD tested the intensity distribution of Ca(OH)₂ and CaCO₃, while FTIR traced the characteristic peaks of C-O functional groups in a specific spectral range to determine the depth of carbonation of concrete. Results indicate that the depth of carbonation values measured by CA, TGA, XRDA, and FTIR are 2-3 times higher than those measured by PI. This research may provide valuable insights for the design of carbonation detection in concrete.