【作者】 张海东； 韦江雄； 李方贤；

【机构】 华南理工大学材料科学与工程学院； 广东省建筑材料低碳技术工程技术研究中心；

【摘要】 本文选取石灰与无定型二氧化硅为原料,利用水热合成法在不同热工条件下制备了水化硅酸钙晶种,研究水化硅酸钙晶种对硅酸盐蒸压制品强度的影响。通过化学分析法探讨了不同蒸压时间下水化硅酸钙晶种对粉煤灰反应程度的影响;利用X射线衍射（XRD）、电子扫描电镜（SEM-EDS）和压汞法（MIP）分析了晶种对不同蒸压时间下CaO-SiO₂-H₂O体系水化产物种类及形貌的影响。研究结果表明:采用钙硅摩尔比为1.0、水热合成温度小于150℃时制备的水化硅酸钙晶种提高CaO-SiO₂-H₂O蒸压体系强度最明显,水化硅酸钙晶种的掺入促进了粉煤灰中SiO₂快速溶出以及水石榴石的分解,提高水化产物含量;水化硅酸钙晶种的加入可以细化孔结构,使孔结构分布均匀,增加50 nm以下无害孔及少害孔数量,减少大于200 nm多害孔数量。更多还原

【Abstract】 The effect of calcium silicate hydrate seed on the CaO-Si02-H20 hydrothermal reaction was studied in the investigation.Calcium silicate hydrate seed were prepared by hydrothermal synthesis with lime and nano silica under different thermal conditions.Chemical analysis method was used for the determination of reactive degree of fly ash.The effect of calcium silicate hydrate seed on types and morphology of hydration products was characterized by X-ray diffraction（XRD）and scanning electron microscopy（SEM-EDS）.The distribution of pore size was investigated by mercury intrusion porosimetry（MIP）.The results indicated that the compression strength of CaO-SiO₂-H₂O autoclaved system increased most boviously mixed with calcium silicate hydrate synthesized under the 150 ℃ with calcium silica ratio 1.0.Calcium silicate hydrate seed promoted dissolution of SiO₂from fly ash and decomposition of hydrogarnet,accelerated the generation of hydration products（mainly C-S-H（B） and tobermorite） so that the products had higher strength.The pore size could be refined and the distribution of the pore size was uniform with the addition of calcium silicate hydrate.The number of pores below 50 nm increased and the number of poresabove 200 nm reduced compared with the reference sample.更多还原