Understanding the aging mechanism of calcium silicate hydrates under the action of solar radiation

Abstract

This work examines the influencing mechanism of light radiation on performances and structures of calcium silicate hydrates (C-S-H) through exposing synthetic C-S-H samples to high-power Xenon radiation. The compositions, chemical structures and nanomorphology of C-S-H were investigated using XRD, TG, ²⁹Si NMR, Ca XANES, Si XANES and TEM. Xenon radiation reduces the chemically bound water content in C-S-H and the drying effect induced by Xenon radiation is more pronounced in C-S-H with lower Ca/Si ratio. Xenon radiation increases the polymerization of C-S-H and elongates the silicate chain by driving separated Si–O tetrahedron to connect with each other without changing its Ca/Si ratio. Furthermore, Xenon radiation reduces the coordination numbers of Ca–O and causes the self-organization of chemical structure at molecular and atomic scales. The existence of portlandite improves the resistance of C-S-H to compositional and structural changes induced by Xenon radiation. These findings pave the way for understanding aging mechanism of cement-based materials under the action of solar radiation.

Graphic Abstract

Keywords:

• xenon radiation
• calcium silicate hydrates (C-S-H)
• aging mechanism
• self-organization

Author contribution

Min Jin: Methodology, Data curation, Formal analysis, Funding acquisition, Writing – Original Draft, Review & Editing. Wenwei Li: Investigation, Validation, Supervision, Conceptualization. Jinhui Tang: Formal analysis, Supervision, Writing – Review & Editing. Yuefeng Ma: Experimental acquisitions, Formal analysis, Data curation, Validation. Yang Zhou: Simulations, Funding acquisition, Supervision. Jiaping Liu: Conceptualization, Funding acquisition, Writing – Review & Editing.

Disclosure Statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Additional information

Funding

The authors acknowledge financial support from National Natural Science Foundation of China (U2040222, 52008097, 52108197), Jiangsu Planned Projects for Postdoctoral Research Funds (2020Z029), the China Postdoctoral Science Foundation funded project (2020M671298, 2021T140114), State Key Laboratory of High Performance Civil Engineering Materials (2021CEM009).