Dharmawardhana C C, Misra A, Ching Wai-Yim
Department of Physics and Astronomy, University of Missouri - Kansas City, 5110 Rockhill Road, Kansas City, MO 64110, USA.
Department of Civil, Environmental, and Architectural Engineering, University of Kansas, 1530 W 15th Street, Lawrence, KS 66045, USA.
Sci Rep. 2014 Dec 5;4:7332. doi: 10.1038/srep07332.
Calcium silicate hydrate (CSH) is the main binding phase of Portland cement, the single most important structural material in use worldwide. Due to the complex structure and chemistry of CSH at various length scales, the focus has progressively turned towards its atomic level comprehension. We study electronic structure and bonding of a large subset of the known CSH minerals. Our results reveal a wide range of contributions from each type of bonding, especially hydrogen bonding, which should enable critical analysis of spectroscopic measurements and construction of realistic C-S-H models. We find the total bond order density (TBOD) as the ideal overall metric for assessing crystal cohesion of these complex materials and should replace conventional measures such as Ca:Si ratio. A rarely known orthorhombic phase Suolunite is found to have higher cohesion (TBOD) in comparison to Jennite and Tobermorite, which are considered the backbone of hydrated Portland cement.
硅酸钙水合物（CSH）是波特兰水泥的主要胶结相，是全球使用的最重要的单一结构材料。由于CSH在各种长度尺度上的结构和化学性质复杂，研究重点已逐渐转向对其原子水平的理解。我们研究了已知CSH矿物的很大一部分的电子结构和键合。我们的结果揭示了每种键合类型的广泛贡献，尤其是氢键，这应该能够对光谱测量进行批判性分析，并构建逼真的C-S-H模型。我们发现总键序密度（TBOD）是评估这些复杂材料晶体凝聚性的理想总体指标，应该取代诸如Ca:Si比等传统指标。与被认为是水化波特兰水泥骨干的硬硅钙石和雪硅钙石相比，一种鲜为人知的正交相索伦石具有更高的凝聚性（TBOD）。
