分子动力学模拟水化硅酸钙的蠕变性能

doi:10.16552/j.cnki.issn1001-1625.2024.1245

摘要/Abstract

摘要： 水化硅酸钙(C-S-H)是水泥基材料最主要的水化产物,其内部存在凝胶孔。C-S-H对混凝土的耐久性有着重要影响,为了探究其在微观结构层面的蠕变变形机制,本文基于C-S-H凝胶分子模型,采用分子动力学模拟研究了C-S-H在不同单轴加载方向和含不同尺寸凝胶孔缺陷情况下的蠕变性能。结果表明:C-S-H在钙硅层面上抗蠕变性能更好,而在垂直于钙硅层方向上抗蠕变性能较差;在蠕变过程中,Ca—O离子键和Si—O共价键抗蠕变性能强于氢键网络结构,且C-S-H的抗压缩蠕变性能优于抗拉伸蠕变性能。微结构的分析表明,C-S-H的蠕变主要起源于层间部分,变形主要由层间原子的位移引起,其中水分子对蠕变变形贡献最为显著。此外,凝胶孔缺陷会降低C-S-H的抗蠕变性能,并显著影响初始蠕变阶段的蠕变速率。

关键词: 水化硅酸钙(C-S-H), 蠕变性能, 分子动力学模拟, 微观机制, 凝胶孔缺陷

Abstract: Calcium silicate hydrate (C-S-H) is the main hydration product of cement-based materials and contains internal gel pores, which significantly influence the durability of concrete. To investigate the creep deformation mechanism of C-S-H at the microstructure level, based on a molecular model of C-S-H gel, the creep performance of C-S-H under different various uniaxial loading directions and with gel pore defects of different sizes were studied by molecular dynamics simulation. The results indicate that C-S-H has better creep resistance along the calcium silicon layer, but poorer creep resistance in the direction perpendicular to layer. During the creep process, the creep resistance of Ca—O ionic bonds and Si—O covalent bonds are stronger than that of hydrogen bonding network structures, and the compressive creep resistance of C-S-H is superior to the tensile creep resistance. Microstructure analysis indicates that the creep primarily originates from the interlayer region, and deformation mainly caused by the displacement of interlayer atoms, among which water molecules make the most significant contribution to creep deformation. Furthermore, the gel pore defects will reduce the creep resistance of C-S-H, and significantly affect the creep rate in the initial creep stage.

Key words: calcium silicate hydrate (C-S-H), creep performance, molecular dynamics simulation, microscopic mechanism, gel pore defect

中图分类号:

TU528

李云丽, 张学林, 吴文平. 分子动力学模拟水化硅酸钙的蠕变性能[J]. 硅酸盐通报, 2025, 44(6): 2036-2045.

LI Yunli, ZHANG Xuelin, WU Wenping. Molecular Dynamics Simulation of Creep Performance of Calcium Silicate Hydrate[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(6): 2036-2045.

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