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目的:揭示水泥基材料中C-S-H凝胶/水泥颗粒界面的尺寸及微观力学特性,为从纳米尺度理解水泥基材料的性能提供依据。创新点:采用动态模量图技术对C-S-H凝胶/水泥颗粒界面微区的尺度及力学行为进行研究,借助动态模量图的高分辨性,可获得该微区精确且有效的信息。方法:对比利用纳米压痕及动态模量图对C-S-H凝胶/水泥颗粒界面进行研究。结论:纳米压痕仅能粗略估计界面微区的尺寸及力学参量,相比之下,动态模量图的分辨率要高出2个数量级(表2),因此可获得更精确的测量值。C-S-H凝胶/水泥颗粒界面的尺寸在250 nm左右,模量值介于60 GPa和70 GPa之间。此界面区可认为是包覆水泥颗粒周围的一层紧密的水化层结构,其致密性将阻止内部水泥的进一步水化。
OBJECTIVE: To reveal the size and micromechanical properties of C-S-H gel / cement particle interface in cement-based materials and to provide a basis for understanding the properties of cement-based materials at nanoscale. Innovative point: The scale and mechanical behavior of C-S-H gel / cement particle interface microdomains are studied by using dynamic modulus diagram. Accurate and effective information of microdomains can be obtained by means of high resolution of dynamic modulo graph. Methods: The interface between C-S-H gel and cement particles was compared by nano-indentation and dynamic modulus diagram. CONCLUSIONS: Nanoindentation can only roughly estimate the size and mechanical parameters of the interface microdomains. In contrast, the resolution of the dynamic modulo graph is two orders of magnitude higher (Table 2), resulting in more accurate measurements. The size of the C-S-H gel / cement particle interface is about 250 nm and the modulus value is between 60 GPa and 70 GPa. This interfacial zone can be thought of as a tight hydration layer surrounding the coated cement particles, and its densification will prevent further hydration of the internal cement.