Multistep crystallization pathways of a new carbonation-hardened Ternesite binder

TY - JOUR

T1 - Multistep crystallization pathways of a new carbonation-hardened Ternesite binder

AU - Li, Yangrui

AU - Yue, Yanfei

AU - Peng, Xueping

AU - Qian, Jueshi

N1 - © 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

PY - 2025/4/15

Y1 - 2025/4/15

N2 - Developing low-carbon clinkers and binding materials is a promising way to achieve net zero in cement industry. Ternesite is a low-carbon clinker mineral in terms of reduced CaO content and sintering temperature. More importantly, its hydration inertness can be compensated by carbonation curing to develop high strength rapidly. This investigation hence aims at disclosing the mechanisms and kinetics associated with carbonation hardening of ternesite. The X-ray diffraction, thermogravimetry, Raman spectroscopy and 29Si nuclear magnetic resonance were used to determine the phase assemblage evolution of carbonated ternesite at different periods, while back-scattered electron microscopy and scanning electron microscopy with energy dispersive spectroscopy were employed to illustrate the microstructure characteristics. The calcium carbonates formed in carbonated ternesite were calcite, aragonite and more interestingly amorphous phase and monohydrocalcite, with the crystallization degree increased with carbonation time. Si transferred into highly polymerized Q 3 and Q 4 units, with content increased with time. This unique carbonation behavior of ternesite should be governed by the competition on “capturing” Ca between C, Si and S. The Ca 2+ is partially combined with SO 4 2− to form gypsum, which leads to decreased Ca/C ratio of calcium carbonate and thus weak crystallization, also lower Ca/Si ratio of silica gel hence higher polymerization degree.

AB - Developing low-carbon clinkers and binding materials is a promising way to achieve net zero in cement industry. Ternesite is a low-carbon clinker mineral in terms of reduced CaO content and sintering temperature. More importantly, its hydration inertness can be compensated by carbonation curing to develop high strength rapidly. This investigation hence aims at disclosing the mechanisms and kinetics associated with carbonation hardening of ternesite. The X-ray diffraction, thermogravimetry, Raman spectroscopy and 29Si nuclear magnetic resonance were used to determine the phase assemblage evolution of carbonated ternesite at different periods, while back-scattered electron microscopy and scanning electron microscopy with energy dispersive spectroscopy were employed to illustrate the microstructure characteristics. The calcium carbonates formed in carbonated ternesite were calcite, aragonite and more interestingly amorphous phase and monohydrocalcite, with the crystallization degree increased with carbonation time. Si transferred into highly polymerized Q 3 and Q 4 units, with content increased with time. This unique carbonation behavior of ternesite should be governed by the competition on “capturing” Ca between C, Si and S. The Ca 2+ is partially combined with SO 4 2− to form gypsum, which leads to decreased Ca/C ratio of calcium carbonate and thus weak crystallization, also lower Ca/Si ratio of silica gel hence higher polymerization degree.

KW - Calcium carbonate

KW - Carbonation curing

KW - Carbonation mechanism

KW - Mechanical property

KW - Ternesite

UR - https://www.scopus.com/pages/publications/85216577672

U2 - 10.1016/j.compositesb.2025.112215

DO - 10.1016/j.compositesb.2025.112215

M3 - Article

SN - 1359-8368

VL - 295

JO - Composites Part B: Engineering

JF - Composites Part B: Engineering

M1 - 112215

ER -