ORCID
- Niall Holmes: 0000-0002-1374-2594
Abstract
Leaching from cement can lead to a loss in performance and durability and can also have an environmental impact. Therefore, it is an important aspect to consider when new cements are being developed and where concrete is to be placed that could lead to the contamination of groundwater. Calibrated thermodynamic models can provide very useful predictions in a matter of seconds for any cement-based material. However, such models need to include accurate representations of the solid-solution nature of the C-S-H gels that are included for the incongruent dissolution of calcium and silica. This study presents the calibration of a thermodynamic model employing the pH-REdox-Equilibrium geochemical software 3.8.7, written in C (PHREEQC 3.8.7), to model the change in the pH and the leaching of calcium (Ca) and silica (Si) from cement against the Ca/Si ratio and over time. The predicted concentrations of Ca and Si and the pH in the leachate were calculated using three solid-solution C-S-H gel models that were taken from the cemdata18 database, namely, CSHQ, CSH3T, and tobermorite–jennite, which have not been analysed before and show good agreement. The calibrated model was used to predict leaching from a CEM II/A-L cement and a blended CEM I + fly-ash with a cement replacement level of 35%. The effect of a sulphate environment (Na2SO4) was also analysed.
Keywords
leaching, cement, calcium, silica, thermodynamic modelling, PHREEQC
DOI Link
Publication Date
2025-01-01
Volume
15
ISBN
2076-3417
Deposit Date
2025-07-28
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.
Additional Links
Recommended Citation
Holmes, Niall and Tyrer, Mark, "Modelling Leaching Using C-S-H Solid Solutions: Applied Sciences" (2025). Research Outputs: 2025-Present. 3.
https://arrow.tudublin.ie/stcero/3