无机外加剂中各离子对水化硅酸钙的影响研究进展

Research progress on the influence of all ions in inorganic additives on hydrated calcium silicate

近年来,随着混凝土技术的发展,外加剂已成为制备混凝土的重要辅助材料,但外加剂引入的各种离子对水化硅酸钙(C-S-H)的结构及形貌有较大影响。因此综合评述了无机外加剂中不同离子对C-S-H组成、结构及微观形貌的影响:Al^(3+)能够直接参与C-S-H结构的构建;Na^(+)、K^(+)、Cl^(-)可以加速水化反应,促进C-S-H凝胶的生成;适量的SO_(4)^(2-)有助于C-S-H结晶,而过量的SO_(4)^(2-)则会降低C-S-H的稳定性。详细分析了上述各离子对C-S-H硅氧四面体聚合度、层间距及平均分子链长的影响和研究进展,并在此基础上研究了无机外加剂中多离子共存对C-S-H结构的影响。无机外加剂对C-S-H硅氧四面体聚合度、层间距及平均分子链长的影响还需进一步研究。

In recent years,with the development of concrete technology,additives have become the important auxi-liary material for preparation of concrete.However,because of the significant influence of various ions in presence of additives on the structure and pattern of hydrated calcium silicate(C-S-H),in this paper the effects of ions contained in inorganic additives on the composition and microstructure of C-S-H were reviewed.Al^(3+)is directly involved in the construction of C-S-H structure,while Na^(+),K^(+)and Cl^(-)facilitate the hydration to produce C-S-H gel.SO_(4)^(2-)at a proper dosage contributes to the crystallization of C-S-H,but the presence of excessive SO_(4)^(2-)will lower the stability of the C-S-H.The effects and research progress of the above-mentioned ions on the polymerization degree,interlayer spacing and averaged length of molecular chain of silicon-oxytetrahedron of the C-S-H were studied in details.On this basis,the influence of the coexistence of various ions in inorganic additives on the structure of C-S-H was presented,especially the influence of inorganic additives on polymerization degree,interlayer spacing and averaged length of molecular chain needs to be further studied.