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.