Coherent diffraction study of calcite crystallization during the hydration of tricalcium silicate

Abstract

The aim of this work is using Bragg coherent X-ray diffraction imaging (BCDI) to study the calcite crystallization during carbonation of hydrated tricalcium silicate (C3S). Portland cement is a very complex synthesized product whose 50~70% mass is composed of C3S, which is the most important phase to produce calcium silicate hydrates and calcium hydroxide. Hence, its hydration contributes greatly to the hydration of cement and later to the carbonation of cement products when it reacts with CO2, often from the air, to form calcium carbonates. BCDI has emerged in the last decade as a promising high-resolution lens-less imaging approach for characterization of various samples. It has made significant progress with the development of Xray sources and phase-retrieval algorithms. BCDI allows for imaging the whole three-dimensional structure of micro-and sub-micro-crystalline materials and can show the strain distribution at the nanometer spatial resolution. Results show that calcite crystallization follows a through-solution reaction and the growth model of the calcite crystal can be explained by using "phase domain" theory. During carbonation, calcite crystals grow by increasing the number of phase domains within them while the domain size remains at about 200~300nm.

Sol–Gel Synthesis of Endodontic Cements: Post-Synthesis Treatment to Improve Setting Performance and Bioactivity

“…In fact, there is an endodontic cement on the market, MicroMega-MTA, with a reduced setting time of 20 min, and the manufacturer claims this reduction due to the addition of CaCO 3 [ 44 ]. Ca(OH) 2 but also C-S-H and unhydrated cement components C3S and C2S can consume CO 2 and get involved in the carbonation process [ 45 ]. It is reported that carbonation leads to reduction in porosity and consolidate the microstructure of the hardened cement paste resulting in an increase of strength [ 45 , 46 ].…”

Physicochemical and Biological Properties of Mg-Doped Calcium Silicate Endodontic Cement

“…After hydration of calcium silicate cement, various by-products were formed according to the hydration duration. Although the hydrated by-products are the same in both C3S and C2S, different reaction processes were provided [ 33 , 35 , 44 , 48 ].…”

“…The CaCO 3 is derived from the surface carbonation of the CH and C-S-H with CO 2 , and these reactions were revealed at Equations (4) and (5) [ 48 ]. According to these processes, calcium carbonate is the last by-product during hydration.…”

“…It is associated with densification and an increase in mechanical strength [ 24 , 33 ]. Also, because the CH has a lower molar volume, the formation of CaCO 3 (which has a higher molar volume) hardened the cement [ 45 , 48 ]. Thus, the mechanical properties of cement getting increased with hydration time [ 45 ].…”

Oxidation-induced three-dimensional morphological changes in Ni nanoparticles observed by coherent X-ray diffraction imaging

“…In most cases, the spatial resolution of the 3D CXDI is still limited to tens of nanometres which is far from resolving individual atoms (Gallagher-Jones et al, 2016). However, 3D CXDI has demonstrated great potential in investigating materials processes involved in catalytic reactions, alloying, dewetting and so forth in a non-destructive manner (Robinson et al, 2016;Liu et al, 2018;Kim et al, 2019Kim et al, , 2020.…”