钙硅摩尔比对纳米水化硅酸钙晶种早强作用的影响及机理  

Effect of Calcium-Silicon Molar Ratio on Early Strength Enhancement of Nano-sized Calcium Silicate Hydrate Seeds

作　　者：唐芮枫 崔素萍[1] 王子明[1] 王肇嘉 张佳乐[1] 兰明章 TANG Ruifeng;CUI Suping;WANG Ziming;WANG Zhaojia;ZHANG Jiale;LAN Mingzhang(Faculty of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China;State Key Laboratory of Soild Waste Utilization and Energy-Saving Building Materials,Beijing Building Materials Research Institute Co.,Ltd.,Beijing 100041,China)

机构地区：[1]北京工业大学材料与制造学部,北京100124 [2]北京建筑材料科学研究总院有限公司,固废资源化利用与节能建材国家重点实验室,北京100041

出　　处：《硅酸盐学报》2022年第6期1626-1633,共8页Journal of The Chinese Ceramic Society

基　　金：北京市自然科学基金-市教委联合资助项目(KZ202010005013)。

摘　　要：纳米C-S-H晶种成核剂通过为水泥水化产物提供成核位点,能有效促进水泥水化进程,提高水泥基复合材料早期强度。研究表明,钙硅摩尔比的变化会影响纳米C-S-H晶种对水泥的早强作用,但具体影响规律尚存争议。本工作通过X射线荧光光谱分析、多重光散射分析、动态光散射分析、X射线衍射分析、透射电子显微镜、水泥水化放热及强度测试研究了钙硅摩尔比对纳米C-S-H晶种尺寸、形貌及其对水泥早强效果的影响,以阐明钙硅摩尔比对纳米C-S-H晶种早强作用的影响规律及作用机理。这对提高纳米C-S-H晶种成核效率,优化纳米C-S-H的制备工艺,推进纳米C-S-H晶种材料的工业化应用具有重要意义。结果表明:随着钙硅摩尔比在1.0~1.7的范围内的增大,纳米C-S-H悬浮液分散稳定性逐渐提高,纳米晶粒越不易团聚;同时,随着钙硅摩尔比的增大,纳米C-S-H逐渐由球状变为锡箔状,颗粒间的堆叠逐渐减小,层厚变薄。纳米C-S-H能显著促进水泥水化放热速率和早期强度的发展,尤其是1 d龄期之内的强度。钙硅摩尔比越高,纳米C-S-H对水泥水化放热速率加快的幅度越大,早期抗压强度提升的幅度越高。Nano-sized C-S-H crystal seed nucleating agent can effectively promote the hydration process of cement and improve the early strength of cementitious composites via providing some nucleation sites for cement hydration products.The calcium-silica molar ratio can affect the early strength effect of nano-sized C-S-H crystalline seeds on cement,but the specific influence law is still controversial.In this paper,the effect of calcium-silica molar ratio on the size and morphology of nano-sized C-S-H crystalline species and their early strength effects on cement was investigated by X-ray fluorescence spectroscopy,multiple light scattering analysis,dynamic light scattering analysis,X-ray diffraction,transmission electron microscopy,cement hydration exotherm and strength tests,and the mechanism of calcium-silica molar ratio affecting the early strength of nano-sized C-S-H crystalline species on cement was elucidated.The results show that the nucleation efficiency of C-S-H nano-crystals can be improved as calcium and silicon molarity is increased.The size of C-S-H nano-crystals gradually becomes smaller and the dispersion stability of suspension improves when calcium-silica molar ratio increases from 1.0 to 1.7.Also,the morphology of C-S-H nano-crystals changes from spherical to tin foil,and the stacking between the crystals decreases and the layer thickness becomes thinner when calcium-silica molar ratio increases.The C-S-H nano-crystals can promote the development of cement hydration exothermic rate and early strength,especially within the age of 1 d.The higher the calcium-silica molar ratio is,the greater the acceleration of cement hydration exothermic rate by C-S-H nano-crystals and the higher the early compressive strength enhancement will be.

关 键 词：纳米水化硅酸钙 钙硅摩尔比 水化 早期强度 晶粒尺寸 形貌 

分 类 号：TU528[建筑科学—建筑技术科学]