A new model for the C-S-H phase formed during the hydration of Portland cements
A new model for the C-S-H phase formed during the hydration of Portland cements
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DOI：
10.1016/j.cemconres.2017.03.001
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发表时间：
2017-07-01
影响因子：
11.4
通讯作者：
Chen, Jeffrey
中科院分区：
文献类型：
--
作者：
Gartner, Ellis;Maruyama, Ippei;Chen, Jeffrey
建立了一个模型来解释为什么在波特兰水泥水化过程中生长的C-S-H相最初需要高水分，而大部分水分在温和干燥时会丢失。提出了硅酸盐缺失(二聚体)类托勃莫来石组成的无水阴离子基片上吸附完全水化的水化钙离子，从而导致硅酸盐水泥中阿利特(C3S)水化过程中C-S-H的快速生长。二价(Ca~(2+))和一价(CaO~+)溶剂化阳离子都被引入以平衡基片的负电荷，导致显著的结构无序，解释了形成的C-S-H结晶不良的性质。由于形成了Si-O-Ca-O-Si桥，一些溶剂化水在第一次干燥时不可逆转地损失，这解释了不可逆收缩。最初形成的C-S-H相对于具有较长硅酸盐链的C-S-H是亚稳定的，随着水和CH的分离，它可能向较长的硅酸链方向缓慢演化。(C)2017爱思唯尔有限公司。保留所有权利。
A model is developed to explain why the C-S-H phase that grows during the hydration of Portland Cements initially requires a high water content, much of which is lost by gentle drying. It is proposed that the rapid growth of C-S-H during the hydration of alite (C3S) in Portland cements initially occurs by adsorption of fully hydrated aqueous calcium cations onto anhydrous anionic basal sheets of a silicate-deficient (dimeric) tobermorite-like composition. Both divalent (Ca2+) and univalent (CaOH+) solvated cations are incorporated to balance the negative charge of the basal sheet, leading to significant structural disorder, explaining the poorly-crystalline nature of the C-S-H formed. Some of the solvation water is lost irreversibly on first drying due to the formation of Si-O-Ca-O-Si bridges, explaining irreversible shrinkage. The initially-formed C-S-H is metastable relative to a form with longer silicate chains, towards which it may slowly evolve with separation of water and CH. (C) 2017 Elsevier Ltd. All rights reserved.