Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/30748
Title: Hydrated Calcium Silicate Erosion in Sulfate Environments a Molecular Dynamics Simulation Study
Authors: You, M
Yin, X
Sun, Y
Wu, H
Li, J
Zhou, X
Keywords: hydrated calcium silicate;sodium sulfate erosion;molecular dynamics;micro-mechanisms
Issue Date: 7-Dec-2024
Publisher: MDPI
Citation: You, M. et al. (2024) 'Hydrated Calcium Silicate Erosion in Sulfate Environments a Molecular Dynamics Simulation Study', Materials, 17 (23), 6005, pp. 1 - 16. doi: 10.3390/ma17236005.
Abstract: To investigate the micro-mechanism of the erosion of hydrated calcium silicate (C-S-H gel) in a sulfate environment, a solid–liquid molecular dynamics model of C-S-H gel/sodium sulfate was developed. This model employs molecular dynamics methods to simulate the transport processes between C-S-H gel and corrosive ions at concentrations of 5%, 8%, and 10% sodium sulfate (Na₂SO₄), aiming to elucidate the interaction mechanism between sulfate and C-S-H gel. The micro-morphology of the eroded samples was also investigated using scanning electron microscopy (SEM). The findings indicate that the adsorption capacity of C-S-H for ions significantly increases with higher concentrations of Na₂SO₄ solution. Notably, the presence of sulfate ions facilitates the decalcification reaction of C-S-H, leading to the formation of swollen gypsum and AFt (ettringite). This process results not only in the hydrolysis of the C-S-H gel but also in an increase in the diffusion coefficients of Na+ and Ca^{2+}, thereby exacerbating the erosion. Additionally, the pore surfaces of the C-S-H structure exhibited strong adsorption of Na^{+}, and as the concentration of Na2SO₄ solution increased, Na^{+} was more stably adsorbed onto the C-S-H pore surfaces via Na-Os bonds. The root-mean-square displacement curves of water molecules were significantly higher than those of SO₄²-, Na^{+} and Ca^{2+}, which indicated that SO₄²- could co-penetrate and migrate with water molecules faster compared with other ions in the solution containing SO₄²- , resulting in stronger corrosion and hydrolysis effects on the C-S-H structure
Description: Data Availability Statement: The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.
URI: http://bura.brunel.ac.uk/handle/2438/30748
DOI: http://dx.doi.org/10.3390/ma17236005
Other Identifiers: ORCiD: Xiangming Zhou https://orcid.org/0000-0001-7977-0718
6005
Appears in Collections:Dept of Civil and Environmental Engineering Research Papers

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