Synchrotron X-ray Raman scattering shows the changes of the Ca environment in C-S-H exposed to high pressure
Synchrotron X-ray Raman scattering shows the changes of the Ca environment in C-S-H exposed to high pressure
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DOI：
10.1016/j.cemconres.2020.106066
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发表时间：
2020-06
影响因子：
11.4
通讯作者：
Jiaqi Li;Wenxin Zhang;P. Monteiro
中科院分区：
文献类型：
--
作者：
Jiaqi Li;Wenxin Zhang;P. Monteiro
X射线拉曼散射（XRS）是一种分析元素局部化学环境的新探针。本文首次将XRS技术应用于水泥研究领域。利用原位高压XRS（HP-XRS）技术研究了C-S-H在20 GPa的偏应力和静水压力联合作用下的Ca环境变化。的钙L2，3-边缘的峰位置系统地转移到较低的能量加载后，表明缩短Casingle bondO键。卸载时，Ca L2，3-边的峰位向高能方向移动，卸载至0 GPa后，L2，3-边的峰位发生了永久性移动，表明永久变形主要是由于层间Ca的变形和层间区域的滑移引起的.首次在原子尺度上证实了C-S-H的压力诱导结构变化。
X-ray Raman Scattering (XRS) is a new probe to analyze the local chemical environment of elements of interest. In this communication, XRS is, for the first time, used in the field of cement study. In situ high-pressure XRS (HP-XRS) at Ca L2,3-edge was used to examine the pressure-induced change of Ca environment of C-S-H under a loading/unloading cycle of combined deviatoric stress and hydrostatic pressure up to 20 GPa. The peak positions of the Ca L2,3-edge systematically shifted to lower energies upon loading, suggesting a shortening of the Casingle bondO bonds. The peak positions of the Ca L2,3-edge shifted to higher energies upon unloading, but permanent shifts in edge positions were observed after unloading to 0 GPa, suggesting a permanent deformation mainly due to a distortion in the interlayer Ca and a sliding at interlayer region. For the first time, the pressure-induced structural change of C-S-H is evidenced at the atomic scale.