The Use of Carbonation Depth Techniques on Stabilized Peat

Abstract

The phenolphthalein indicator method, the pH of slurries method, X-ray powder diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FTIR) are all commonly associated with evaluating the carbonation front depth in concrete. Recent research (using a closed chamber method) has indicated that stabilized peat is a net sink of carbon dioxide (CO2) (at least in the short term), as the binder takes in CO2 both from the atmosphere and any CO2 released by oxidized peat. Therefore, the application of carbonation depth techniques to stabilized peat are of interest and are explored in this paper for the first time as a precursor to developing a greater understanding of the carbonation process in this material. The carbonation fronts obtained by XRD, loss on ignition, and FTIR all arose at similar depths, as these methods all identify the depth at which the calcium carbonate concentration is elevated with respect to the baseline (i.e., the maximum advancement of the carbonation front). In contrast, the phenolphthalein method underestimated the carbonation front considerably. The pH of the stabilized peat slurries method gave the depth at which leaching of calcium hydroxide and calcium ions occurred, rather than a carbonation depth, and exceeds the depths determined from the other techniques. Advantages and disadvantages of all techniques are discussed.

Application of Fourier Transform infrared spectroscopy (FTIR) coupled with multivariate regression for calcium carbonate (CaCO3) quantification in cement

“…In this context, it is essential to: (i) quantify the carbonation reaction products, (ii) control the carbonation process and (iii) understand its effects on the cement integrity and properties. Thus, techniques such as phenolphthalein test, X-ray florescence (XRF), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray microtomography (MicroCT), thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy are widely applied in the literature to characterize carbonated cementitious materials and their composites [32,[35][36][37][38]. Among the characterization methods, the analysis of CaCO 3 in cementitious materials can be performed in the following way: (i) qualitative, by means of phenolphthalein, TEM and SEM methods, (ii) semi-quantitative, using the IR, MicroCT, XRD and XRF instruments and (iii) quantitative, through TGA analysis [11,[35][36][39][40].…”

“…Thus, techniques such as phenolphthalein test, X-ray florescence (XRF), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray microtomography (MicroCT), thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy are widely applied in the literature to characterize carbonated cementitious materials and their composites [32,[35][36][37][38]. Among the characterization methods, the analysis of CaCO 3 in cementitious materials can be performed in the following way: (i) qualitative, by means of phenolphthalein, TEM and SEM methods, (ii) semi-quantitative, using the IR, MicroCT, XRD and XRF instruments and (iii) quantitative, through TGA analysis [11,[35][36][39][40]. In addition, XRD, SEM, IR and TGA can be applied, with their respective limitations, to identify the presence of different CaCO 3 polymorphs (amorphous carbonate, vaterite, aragonite and calcite) [31,[41][42].…”

The Influence of Water/Binder Ratio on the Mechanical Properties of Lime-Based Mortars with White Portland Cement

“…This method, although not very precise, was chosen as the fastest and easily visible. Other more precise methods for measuring the carbonation depth (X-ray Diffraction Analysis, Fourier Transform Infrared Spectroscopy, Thermo-gravimetric Analysis and Loss on Ignition, Dust digestion [34] required special equipment and trained professionals for the application, to which the authors had no access.…”

Evidence of Stabilized Peat as a Net Carbon Sink

“…This confirms that CO2 was being absorbed by the cement throughout the experiment. An in-depth review of the application of carbonation depth techniques to stabilised peat is provided by Duggan et al (2017).…”