Work

Influence of gypsum and KOH on the hydration of pure triclinic C3S

Year: 2025

Type: article

Abstract: This work focuses on the isolated and combined influence of gypsum and KOH on the hydration of pure triclinic C 3 S. The addition of gypsum shows a prolonged induction period and increased maximum reaction rates during C 3 S hydration. These effects are further enhanced when KOH is added. Pore solution composition from ICP-OES measurements of suspension experiments show pore solutions dominated by an equilibrium with gypsum. Resulting changes in C-S-H interfacial precipitation rates are qualitatively correlated with either a prolonged or shortened induction period. A comparison of C 3 S reaction rates calculated based on C-S-H interfacial precipitation rate model and C 3 S reaction rates observed by XRD and TGA show an accurate quantitative description of the C 3 S hydration in the presence of gypsum and KOH. In the combined presence of KOH and gypsum, higher C-S-H surface areas quantitatively explain the increase in C 3 S reaction rates regarding the decreased interfacial precipitation rates. • Decreased C-S-H interfacial precipitation rate by gypsum addition prolongs C 3 S induction period. • Increased C-S-H surface area by gypsum addition leads to increased C 3 S maximum reaction rates. • Additional KOH enhances both effects in the presence of gypsum.

Source: Construction and Building Materials

DOI: 10.1016/j.conbuildmat.2025.142679

Authors: F. Becker, D. Wagner, F. Bellmann, J. Neubauer

Institutions: Friedrich-Alexander-Universität Erlangen-Nürnberg, Bauhaus-Universität Weimar

Language: English

Topic: Concrete and Cement Materials Research

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,540

Funder: Deutsche Forschungsgemeinschaft