Immobilization of Ca 2+ by OH − ions on calcium silicate hydrates
Abstract
ions overcompensates the negative surface charge of C-S-H, originating from deprotonated silanol groups, thereby forming a surface adsorption network. This mechanism is governed by the interplay between solution pH and calcium speciation, where higher pH values favor the formation of calcium-hydroxide solution complexes. Consequently, an increase in pH leads to a higher Ca/Si ratio in C-S-H and a greater adsorption of these complexes, further increasing the effective surface charge density. Conversely, a reduction in pH promotes ion desorption, leading to a progressive decrease in the Ca/Si ratio and decrease in the effective surface charge. These findings provide new insights into the long-term compositional evolution of C-S-H in cement paste, with implications for phase stability, mechanical performance, and concrete durability.
Fields of Study & Subjects
Concrete and Cement Materials Research
Calcium Carbonate Crystallization and Inhibition
Concrete Properties and Behavior
Publication details
- Journal / source
- Physical Chemistry Chemical Physics
- Publisher
- Royal Society of Chemistry (RSC)
- Volume
- 28
- Issue
- 3
- Pages
- 2678–2688
- Publication date
- 1 January 2026
- Language
- EN