Micro-Mechanical Properties of Individual Phases in Cement Pastes under Brine Solution Using Nanoindentation and Scanning Electron Microscopy
Micro-Mechanical Properties of Individual Phases in Cement Pastes under Brine Solution Using Nanoindentation and Scanning Electron Microscopy
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DOI：
10.4028/www.scientific.net/jnanor.46.31
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发表时间：
2017-01-01
影响因子：
1.7
通讯作者：
Ding, Qingjun
中科院分区：
文献类型：
--
作者：
Li, Yue;Wang, Peng;Ding, Qingjun
了解中国西部盐湖环境下的水泥基材料的微型机械性能和微观结构可以为耐用性设计提供科学基础。在这项研究中，制备了水泥糊（（w/c = 0.35）和（w/c = 0.53））并浸泡在盐水溶液中以进行干湿周期测试，其化学成分类似于盐湖解决方案。在扫描电子显微镜（SEM）和能量色散光谱仪（EDS）下观察并分析了腐蚀区域和腐蚀产物的显微照片。通过纳米识别测试了不同相的微型机械性能，并通过高斯功能对压痕模量和压痕硬度的实验频率分布进行了多峰拟合。同时，总结了在腐蚀的水泥糊中的水合物的微型机械性能的统计分布，其中包括低密度钙硅酸盐 - 硅酸盐 - 水疗（LD C-S-S-H凝胶），高密度钙硅酸盐 - 硅酸盐 - 硅酸盐水平（HD C-S-H-H凝胶）和氢氧化钙（CH）。结果表明，盐水腐蚀后水泥糊中每个相的微型机械性能显着降低。另外，水泥比对微型机械性能的影响很小，但对每个阶段的体积分数的影响很大。
Understanding the micro-mechanical properties and the microstructure of cement-based materials under the saline lake environment in western China can provide a scientific basis for the durability design. In this study, cement pastes ((w/c= 0.35) and (w/c= 0.53)) were prepared and soaked in brine solution to carry out the dry-wet cycle test, the chemical composition of which is similar to saline lake solution. The micrographs of corroded regions and corrosion products were observed and analyzed under scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Micro-mechanical properties of different phases were tested by nanoindentation, and multi-peaks fitting was carried out for the experimental frequency distributions of the indentation modulus and indentation hardness by Gaussian function. In the meantime, the statistical distribution of micro-mechanical properties was summarized for the hydrates in corroded cement paste, which has included the low density calcium-silicate-hydrates (LD C-S-H gel), high density calcium-silicate-hydrates (HD C-S-H gel) and calcium hydroxide (CH). The results show that micro mechanical properties of each phase in cement paste after brine corrosion decreased significantly. In addition, the water-cement ratio has little effect on the micro mechanical properties, but much effect on volume fraction of each phase.