I型缺陷C-S-H凝胶相热稳定性的反应分子动力学研究

doi:10.16552/j.cnki.issn1001-1625.2024.1301

摘要/Abstract

摘要： 在高温条件下,C-S-H凝胶中缺陷和受限水的存在显著影响其强度和耐久性。本研究采用反应分子动力学方法,研究了I型缺陷C-S-H凝胶在高温环境下的分子结构特征和反应性。研究发现:温度和Ca/Si比升高导致水分子流动性增强,加速其渗入层状结构,降低结构有序性和连通性,引起Q¹和Q⁰增加,削弱C-S-H凝胶的热稳定性;I型缺陷使C-S-H凝胶沿层间方向膨胀,且随温度和Ca/Si比升高,膨胀率增大;在高温、高Ca/Si比条件下,水分子反应性增强,促进水解反应和羟基形成,I型缺陷快速扩展,显著影响凝胶结构稳定性。本研究成果可为改善混凝土在火灾等极端环境下的性能提供理论支持。

关键词: C-S-H凝胶, 高温环境, I型缺陷, 钙硅比, 分子动力学模拟, 反应分子动力学

Abstract: Under high temperature conditions, the presence of defects and confined water in C-S-H gel significantly affects its strength and durability. This study employed reactive molecular dynamics to investigate the molecular structural characteristics and reactivity of type I defect C-S-H gel under high temperature environments. The findings reveal that the increase in temperature and Ca/Si ratio enhances the mobility of water molecules, accelerating their penetration into the layered structure, reducing structural order and connectivity, leading to an increase in Q¹ and Q⁰, and weakening the thermal stability of C-S-H gel. Type I defect causes the C-S-H gel to expand along the interlayer direction, and the expansion rate increases with rising temperature and Ca/Si ratio. Under high temperature and high Ca/Si ratio conditions, the reactivity of water molecules is enhanced, promoting hydrolysis reactions and the formation of hydroxyl groups, and type I defect rapidly expands, significantly affecting the structural stability of gel. The results of this study provide theoretical support for improving the performance of concrete in extreme environments such as fires.

Key words: C-S-H gel, high temperature environment, type I defect, Ca/Si ratio, molecular dynamics simulation, reactive molecular dynamics

中图分类号:

TU528.1

孙明, 汤庆印, 郭浩然, 王攀, 袁雄洲. I型缺陷C-S-H凝胶相热稳定性的反应分子动力学研究[J]. 硅酸盐通报, 2025, 44(6): 2046-2059.

SUN Ming, TANG Qingyin, GUO Haoran, WANG Pan, YUAN Xiongzhou. Reactive Molecular Dynamics Study on Thermal Stability of Type I Defect C-S-H Gel Phase[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(6): 2046-2059.

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