Reactive Molecular Simulation on Water Confined in the Nanopores of the Calcium Silicate Hydrate Gel: Structure, Reactivity, and Mechanical Properties

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• 作者：Dongshuai Hou ; Tiejun Zhao ; Hongyan Ma ; Zongjin Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 22, 2015
• 年：2015
• 卷：119
• 期：3
• 页码：1346-1358
• 全文大小：1025K
• ISSN：1932-7455

文摘

Calcium silicate hydrate (C鈥揝鈥揌) is a mesoporous amorphous material with water confined in the gel pores, which provides the medium for investigating the structure, dynamics, and mechanical properties of the ultraconfined interlayer water molecules. In this study, C鈥揝鈥揌 gels with different compositions expressed in terms of the Ca/Si ratio are characterized in the light of molecular dynamics. It is found that with increasing Ca/Si ratio, the molecular structure of the silicate skeleton progressively transforms from an ordered to an amorphous structure. The calcium silicate skeleton, representative of the substrate, significantly influences the adsorption capability, reactivity, H-bond network, and mobility of the interlayer water molecules. The structures were tested for mechanical properties by simulated uniaxial tension, and the mechanical tests associated with structural analysis reveal that the stiffness and cohesive force of C鈥揝鈥揌 gel is weakened by both breakage of silicate chains and penetration of water molecules. In addition, the reactive force field is coupled with both the mechanical response and chemical response during the large tensile deformation process. On the one hand, the silicate chains, acting in a skeletal role in the layered structure, depolymerize to enhance the loading resistance. On the other hand, water molecules, attacking the Si鈥揙 and Ca鈥揙 bonds, dissociate into hydroxyls, which are detrimental to the cohesive force development.