Hydration and carbonation of monoclinic C₂S and C₃S studied by Raman spectroscopy

Abstract

We present a micro-Raman study on the hydration and carbonation of the main silicate phases of Portland cement, i.e. monoclinic dicalcium silicate (C 2 S) and monoclinic tricalcium silicate (C 3 S). We investigate the reaction products and the loss of crystallinity induced by hydration on these two compounds. In the CO 2 -contaminated pastes we find that calcite, aragonite, and vaterite are inhomogeneously formed. We study sample cross sections to evaluate the maximum depth at which CaCO 3 is formed. We find that carbonation is limited to the first 500-1000 µm from the surface in the C 3 S pastes, while in C 2 S pastes CaCO 3 is formed well beyond this depth. Our results show the great potential of Raman spectroscopy in the study of the chemistry of cements.

Use of micro‐Raman spectroscopy to study reaction kinetics in blended white cement pastes containing metakaolin

“…More specifically, no references can be found on the use of Raman spectroscopy to track the pozzolanic reaction. Earlier papers identified clinker, [7] anhydrous, [8,9] or hydrated [10] cement phases, but the technique has never been applied to identify the phases formed in metakaolin-blended Portland cement hydration. For that reason, the present study used Raman spectroscopy to explore the effect of curing temperature and MK content on the reaction kinetics of MK-blended cement phase systems.…”

Characterisation of carbonated Portland cement paste with optical fibre excitation Raman spectroscopy

“…In contrast, under the fingerprint characterisation capacity of Raman spectroscopy [10,11], the reaction products of various deterioration mechanisms, such as calcium carbonate polymorphs (e.g., calcite, vaterite and aragonite) [12][13][14][15][16][17][18][19] from carbonation and sulphatebearing products (i.e., gypsum, ettringite and thaumasite) [20][21][22][23] from sulphate attack , can be clearly differentiated by their unique vibration bands (wavenumber in cm -1 ) and this can effectively overcome the limitations of ES. Moreover, as Raman spectroscopy works on the principle of intrinsic vibration of molecules, the chemical dyes as employed in the FOS is no longer needed which can totally eliminate the long-term instability and irreversibility issues facing FOS.…”

Confocal Raman Microscopy: new perspective on the weathering of anhydrous cement

“…1095 cm -1 assigned to CaCO3 spectrum and another more intense Raman band located at ca. 992 cm -1 [4]. The Raman bands associated with CaCO3 are not abundant and therefore their presence in the average Raman spectrum is low when compared with the main Raman bands.…”

“…The use of Raman spectroscopy in the characterization of the various cements and supplementary cementitious materials (SCMs) has been investigated over the last four decades [1][2][3][4]. However, in 2013, Schmid et al [5] published the first successful and to date only Raman imaging study on cementitious materials.…”