碱金属掺杂对硫硅酸钙水化性能的影响机理  

Alkali Metal Doping Influence on Hydration Properties of Ternesite

作　　者：张文生 刘垒 任雪红 张洪滔 叶家元 张江涛 曹立学 安楠 钱觉时[2] ZHANG Wensheng;LIU Lei;REN Xuehong;ZHANG Hongtao;YE Jiayuan;ZHANG Jiangtao;CAO Lixue;AN Nan;QIAN Jueshi(State Key Laboratory of Green Building Materials,China Building Materials Academy,Beijing 100024,China;College of Materials Science and Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]中国建筑材料科学研究总院有限公司绿色建筑材料国家重点实验室,北京100024 [2]重庆大学材料科学与工程学院,重庆400045

出　　处：《硅酸盐学报》2023年第2期290-302,共13页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金重点项目(51832006);国家自然科学基金面上项目(51772281);中国建材集团攻关专项资助项目(2021HX0304)。

摘　　要：碱金属离子作为水泥原料中常见的杂质离子,其存在会影响熟料矿物结构与性能。采用分析纯试剂合成碱金属掺杂的硫硅酸钙单矿物,借助等温量热仪、综合热分析、扫描电镜和^(29)Si核磁共振等手段,研究了碱金属离子对硫硅酸钙水化活性及力学性能的影响。结果表明:碱金属离子在硫硅酸钙晶体结构中的固溶,能够降低晶体结晶度,形成晶体缺陷,有效提升硫硅酸钙早期水化活性,促进其早期力学性能快速发展。同时,碱金属的掺杂能够改变水化硅酸钙(C–S–H)凝胶等产物的微观形貌及结构。其中,Li_(2)O掺杂能够稳定絮状形态的C–S–H凝胶,而Na_(2)O和K_(2)O掺杂能够诱导C–S–H凝胶纤维状生长。经碱金属掺杂影响,C–S–H凝胶聚合度有所增加,平均硅链长增长。Alkali metal ions as some impurity ions in cement raw materials can affect the structure and properties of clinker minerals.The effect of alkali metal ions on the hydration activity and mechanical properties of ternesite was investigated with alkali-doped ternesite synthesized as analytical reagents by isothermal calorimetry,comprehensive thermal analysis,scanning electron microscopy and ~(29)Si solid state nuclear magnetic resonance.The results show that the solid solution of alkali metal ions in the crystal structure of ternesite reduces the crystallinity of formed crystals,forms the crystal defects,effectively improves the early hydration activity of ternesite,and promotes the rapid development of its early mechanical properties.Meanwhile,the addition of alkali metal can change the microstructure and structure of calcium silicate hydrates (C–S–H).Among them,Li_2O addition stabilizes the flocculent C–S–H,while Na_2O and K_2O addition can induce the fibrous growth of C–S–H.The degree of polymerization and mean silicon chain length of C–S–H increase due to the addition of alkali metal.

关 键 词：硫硅酸钙 碱金属 水化活性 力学性能 水化硅酸钙凝胶 微观形貌 

分 类 号：TQ172.11[化学工程—水泥工业]