Can iron-doped calcium aluminates activate ternesite hydration?

TY - JOUR

T1 - Can iron-doped calcium aluminates activate ternesite hydration?

AU - Li, Yangrui

AU - Yue, Yanfei

AU - Qian, Jueshi

AU - Bai, Yun

N1 - Publisher Copyright: © 2025 Elsevier Ltd

PY - 2026/2

Y1 - 2026/2

N2 - The hydration inertness of ternesite (C5S2Š) is the primary barrier to the promotion of Ternesite-Ye'elimite Cement (TYC). This study investigated the potential of iron-doped calcium aluminates to activate the hydration of TYC systems, with particular focus on their roles in enhancing the reactivity of C5S2Š. Three types of calcium aluminates, viz. orthorhombic ye'elimite (C4A3Š), iron-doped cubic ye'elimite (C4(A,F)3Š) and ferrite (C4AF), as well as C5S2Š were synthesized in the laboratory. These four minerals, and three blends formulated by mixing each calcium aluminate with C5S2Š, were mixed with water to obtain a total of seven paste mixtures. Their hydration processes were examined using ICC, XRD, FT-IR, TG, and pore solution chemistry analysis to elucidate the influence of iron-doped calcium aluminates (C4(A,F)3Š and C4AF) on the hydration reactivity of C5S2Š and the corresponding mechanisms. Results show that C4(A,F)3Š significantly enhanced the hydration reactivity of C5S2Š by providing reactive amorphous (A,F)H3 to consume gypsum from the hydration of C5S2Š. Evidently, iron doping exhibited a gypsum-like acceleration effect on the hydration of C5S2Š + C4(A,F)3Š system, albeit through a distinct chemical pathway. However, C4AF demonstrated quite limited effect on the C5S2Š + C4AF system, due to the gradual formation of a gel layer on the C4AF surface that restricted further hydration.

AB - The hydration inertness of ternesite (C5S2Š) is the primary barrier to the promotion of Ternesite-Ye'elimite Cement (TYC). This study investigated the potential of iron-doped calcium aluminates to activate the hydration of TYC systems, with particular focus on their roles in enhancing the reactivity of C5S2Š. Three types of calcium aluminates, viz. orthorhombic ye'elimite (C4A3Š), iron-doped cubic ye'elimite (C4(A,F)3Š) and ferrite (C4AF), as well as C5S2Š were synthesized in the laboratory. These four minerals, and three blends formulated by mixing each calcium aluminate with C5S2Š, were mixed with water to obtain a total of seven paste mixtures. Their hydration processes were examined using ICC, XRD, FT-IR, TG, and pore solution chemistry analysis to elucidate the influence of iron-doped calcium aluminates (C4(A,F)3Š and C4AF) on the hydration reactivity of C5S2Š and the corresponding mechanisms. Results show that C4(A,F)3Š significantly enhanced the hydration reactivity of C5S2Š by providing reactive amorphous (A,F)H3 to consume gypsum from the hydration of C5S2Š. Evidently, iron doping exhibited a gypsum-like acceleration effect on the hydration of C5S2Š + C4(A,F)3Š system, albeit through a distinct chemical pathway. However, C4AF demonstrated quite limited effect on the C5S2Š + C4AF system, due to the gradual formation of a gel layer on the C4AF surface that restricted further hydration.

KW - Ferrite

KW - Ternesite

KW - Ye'elimite

KW - Aluminum hydroxide

KW - Hydration reactivity

UR - https://www.scopus.com/pages/publications/105020829685

U2 - 10.1016/j.cemconres.2025.108085

DO - 10.1016/j.cemconres.2025.108085

M3 - Article

SN - 0008-8846

VL - 200

JO - Cement and Concrete Research

JF - Cement and Concrete Research

M1 - 108085

ER -