Influence of triethanolamine on the hydration product of portlandite in cement paste and the mechanism

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• 作者：Zhang Yan-Rong^a ; ^b ; Kong Xiang-Ming^a ; ^{kxm@mail.tsinghua.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Lu Zi-Chen^a ; Lu Zhen-Bao^a ; Zhang Qing^a ; Dong Bi-Qin^c ; Xing Feng^c
• 关键词：Triethanolamine ; Portlandite ; Cement pastes ; Crystal ; Complexation
• 刊名：Cement and Concrete Research
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：87
• 期：Complete
• 页码：64-76
• 全文大小：3302 K

文摘

The influences of triethanolamine (TEA) on the portlandite in hardened cement pastes (HCPs) were systematically investigated. Results show that the addition of TEA in cement pastes leads to a visible reduction of Ca(OH)₂ (CH) content and considerably alters the morphology of CH crystals from large and parallel-stacked lamellar shape to smaller and distorted actinomorphic one. For the first time, the CH micro-crystals and even non-crystalline CH in HCPs were observed in the presence of TEA. Due to integration of CH micro-crystals in C–S–H phase, remarkable higher Ca/Si ratio of C–S–H phase was found. The formation of TEA-Ca^2 + complex via the interaction between Ca^2 + and the oxygen atoms in TEA molecule was evidenced by the results of NMR and UV. It is believed that TEA can be introduced into the crystallization process of portlandite and thus significantly alters the morphology of CH crystals and even the content of the crystalline CH phase.