Statistical Characteristics of Microhardness of Hardened Cement Paste
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2018年第4期
论文作者：党玉栋 SHI Xianming QIAN Jueshi JIANG Yan LI Xincheng
文章页码：924 - 931
摘 要：Due to the intrinsic nature of a heterogeneous and anisotropic microstructure of cement based materials and the small indentation size, the measured microhardness values are subject to considerable variability. This work presents an in-depth assessment of microhardness of hardened cement pastes（HCPs） from a statistical perspective. Hundreds of microhardness measurements were conducted on an HCP sample using a Vickers Microhardness Tester. The results showed that the microhardness measured from the HCP sample significantly scattered with a large standard deviation, varying from tens to hundreds. The data-set of microhardness values was not normally distributed but fit best with a three-parameter lognormal model. By using a statistical software, the probability density function of the microhardness distribution can be readily obtained. The arithmetic mean and its 95% confidence intervals of the measured microhardness values can be used to best represent the microhardness characteristics of HCPs.
党玉栋1,2，SHI Xianming3，QIAN Jueshi4，JIANG Yan5，LI Xincheng1,2
1. Yunnan Institute of Building Research2. Yunnan Key Laboratory of Building Structure and New Materials3. Department of Civil and Environmental Engineering, Washington State University4. College of Materials Science and Engineering, Chongqing University5. School of Materials Science and Engineering, Tongji University
摘 要：Due to the intrinsic nature of a heterogeneous and anisotropic microstructure of cement based materials and the small indentation size, the measured microhardness values are subject to considerable variability. This work presents an in-depth assessment of microhardness of hardened cement pastes（HCPs） from a statistical perspective. Hundreds of microhardness measurements were conducted on an HCP sample using a Vickers Microhardness Tester. The results showed that the microhardness measured from the HCP sample significantly scattered with a large standard deviation, varying from tens to hundreds. The data-set of microhardness values was not normally distributed but fit best with a three-parameter lognormal model. By using a statistical software, the probability density function of the microhardness distribution can be readily obtained. The arithmetic mean and its 95% confidence intervals of the measured microhardness values can be used to best represent the microhardness characteristics of HCPs.
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