Carbonation study and determination of cement to sand ratio in hardened cement mortar by X‐ray photoelectron spectroscopy

Abstract

The determination of cement and sand content in an aged cement mortar is a challenging problem for civil engineers. Techniques like x‐ray diffraction (XRD), thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS) are well established, which can give some insight of the hydrated products. The present study is an attempt to use x‐ray photoelectron spectroscopy (XPS) technique for the evaluation of ordinary Portland cement (OPC), sand (aggregate) composition and carbonation study in hardened cement mortar. Carbonation analysis and cement to sand ratio for all mortar compositions has been determined and studied in detail in the present work. The C 1s spectra of cement mortar with ratios 1:1, 1:3 and 1:6 shows carbonate formation on the surface with 21, 40 and 32 atomic percent, respectively. An increase in SiO2 content corresponding to sand is observed for all three mortar mix. The formation of silica gel due to carbonation has not been observed in the mortar samples. The cement to sand ratio for all three mortar mixes is found to be in 20–30 percent error limit due to the heterogeneous nature of the mortar system.

Incorporation and solidification mechanism of manganese doped cement clinker

“…The XPS narrow spectra of C 1s, Mn 2p, O 1s, and Si 2p for blank and 1% Mn doped CM samples are shown in Figure 3 , and the spectra of the other Mn doped CM samples are provided in Supplementary Figure S1 . The C 1s peaks identified at 284.8, 285.7, and 289.6 eV were the binding energies of contamination adventitious carbon, which accounted for the C-C, C-O-C, and O-C=O components, respectively ( Kalina et al, 2014 ; Singh et al, 2020 ). The bonding energy situated at 293.2 eV accounted for C-F, which may form due to the presence of fluorite in the RMs.…”

“…In the O 1s spectrum, the 529.8 eV peak energy was attributed to Ca-O and Mn-O, and the 532.0 eV peak energy was attributed to Si-O ( Wang et al, 2016 ). The typical peak at 102.7–102.5 eV was assigned to SiO 2 , and the peak at 101.9–101.7 eV was assigned to Si in belite ( Estokova et al, 2018 ; Singh et al, 2020 ). The other O 1s spectrum for Mn doped CM samples is provided in Supplementary Figure S2 .…”

“…The routinely used measurement techniques (e.g., X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM)) can provide chemical and physical information, such as the chemical composition, morphology, and particle size distribution ( Contessi et al, 2021 ; Polavaram and Garg, 2021 ). Additionally, X-ray photoelectron spectroscopy (XPS), can be used for the surface characterization of the clinker composition ( Kalina et al, 2014 ; Singh et al, 2020 ). The binding energy corresponding to specific elements will shift as the chemical bonding environment changes, which provides useful information for elemental analysis ( Black et al, 2003 ).…”

Investigation of glassy phase silica in low calcium content fly ash by X‐ray photoelectron spectroscopy

“…28 The energy resolution of the XPS instrument used in the present study lies in the range of 0.4-0.6 eV, and the details are mentioned elsewhere. 29 The quantification in terms of atomic concentration of the individual elements of multiple oxidation states of a particular element can be calculated according to the formula:…”