| 摘要: |
| 利用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、27Al和29Si魔角旋转固体核磁共振（MAS NMR）以及1H-29Si魔角旋转交叉极化固体核磁共振（1H-29Si CPMAS NMR）研究了NaOH激发碱矿渣水泥早期反应产物的演变过程.结果表明：碱矿渣水泥在3~28 d龄期内均能观察到水化硅铝酸钙凝胶（C-A-S-H）、水滑石和单硫型水化硫铝酸钙（AFm），凝胶产物由复杂的端链硅氧四面体（Q1）、链状硅氧四面体（Q2）和Al取代的链状硅氧四面体（Q2（1Al））或层状硅氧四面体（Q3（1Al））构成，相对反应程度随龄期延长而增大；随着24 h内早期反应的进行，矿渣水化程度提高，铝硅比增大，铝氧四面体桥氧结构占比增大；矿渣铝氧多面体经历结构解聚、水滑石与AFm层状晶体的形成和Q2（1Al）的形成过程；反应早期24 h内Q2（1Al）迅速发展，水分子与硅氧四面体骨架交联，化学结合水形成，未发现聚合度更大的层状硅氧四面体（Q3）和Q3（1Al）结构，因此0~24 h为C-A-S-H低聚态凝胶形成阶段. |
| 关键词: 碱矿渣水泥 微观结构 水化早期 产物演变 |
| DOI：10.3969/j.issn.1007-9629.2024.05.001 |
| 分类号:TQ172.79 |
| 基金项目:陕西省自然科学基金资助项目（2023-JC-YB-096） |
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| Microstructural Evolution of Early Reaction Products in Alkali-Activated Slag Cement at Early Age |
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XIAO Jianmin, LI Hui, LEI Ruixin
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College of Materials Science and Engineering， Xi’an University of Architecture and Technology， Xi’an 710055， China
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| Abstract: |
| The microstructural evolution of early reaction products of alkali-activated slag（AAS） pastes was investigated by X-ray diffraction（XRD）， Fourier transform infrared spectroscopy（FTIR）， 27Al and 29Si magic-angle spinning solid-state nuclear magnetic resonance（MAS NMR） and 1H-29Si cross polarization magic-angle spinning solid-state nuclear magnetic resonance（1H-29Si CPMAS NMR）. The results reveal that calcium aluminium silicate hydrate gel （C-A-S-H）， hydrotalcite and single sulfur hydrated calcium sulfoaluminate（AFm） are found in AAS pastes in 3-28 d. The C-A-S-H gel is a complex structure of end chain tetrahedra（Q1）， branching chain tetrahedra（Q2）， Al-replacing chain tetrahedra（Q2（1Al）） or Al-replacing layered tetrahedra（Q3（1Al）） . The degree of reaction increases with prolongation of hydration time. The hydration degree of slag， Al/Si molar ratio and proportion of bridging tetrahedra that is occupied by Al increase with the early 24 h hydration reaction of AAS cement. Aluminum oxygen polyhedral of slag undergoes the process of structural depolymerization， the formation of layered crystals of hydrotalcite and AFm， and the formation of Q2（1Al）. In the early 24 h of the reaction， Q2（1Al） develops rapidly and water molecules are crosslinked with silicon oxygen backbone； at the same time chemical combined water is formed， the layered tetrahedra（Q3） and Q3（1Al） structures with higher polymerization degree are not found. Consequently， the 0-24 h reaction stage is the C-A-S-H oligomer gel formation stage. |
| Key words: alkali-activated slag cement microstructure early hydration time product evolution |
