摘要
为了提高CaSO_(4)晶须-水泥石的力学性能,采用正硅酸乙酯(TEOS)对晶须表面进行处理,改善晶须与水泥石间的界面。通过红外光谱仪、扫描电子显微镜、X射线衍射仪、X射线光电子能谱仪及接触角测试仪研究了改性CaSO_(4)晶须表面的组成与特性。结果表明,正硅酸乙酯的水解产物与CaSO_(4)晶须表面的羟基发生反应,在CaSO_(4)晶须表面形成了稳定的、无定形态的SiO_(2)。力学性能测试结果表明,改性CaSO_(4)晶须能进一步提高水泥石的力学性能。通过扫描电子显微镜、孔径分布测试研究了晶须及水泥材料界面的微观结构、水化产物和水泥石的结构,揭示了改性CaSO_(4)晶须增强水泥石的作用机理。改性CaSO_(4)晶须表面包覆的SiO_(2)与水泥基材料中游离的Ca(OH)_(2)发生水化反应,促进更多水化产物如水化硅酸钙凝胶(C-S-H)的形成,使得晶须被周围水化产物紧密包裹,增强了晶须与水泥基材料之间的界面黏结作用,迫使裂缝在发展的过程中消耗更多的能量。并且,水化反应的进行也提高了水泥石结构的致密性,从而进一步提高了水泥石的力学性能。
In order to further improve the mechanical properties of the cement stone with CaSO_(4) whisker,the surface of the whisker was modified via tetraethylorthosilicate(TEOS)to improve the interface bonding property between the whisker and the cement stone.The surface composition and properties of the modified CaSO_(4) whisker were investigated by Fourier transform infrared spectroscopy,scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,contact angle measurement.The results show that the hydrolysate of TEOS reacts with the hydroxyl groups on the surface of CaSO_(4) whisker and forms the stable amorphous SiO_(2) on the surface of CaSO_(4) whisker.Based on the results by mechanical properties test,the modified CaSO_(4) whisker can further improve the mechanical properties of cement.The microstructure of the interface between the whisker and the cement material,the hydration products,the structure of the cement stone,were analyzed by scanning electron microscopy and pore size distribution test,which reveals the action mechanism of modified CaSO_(4) whisker reinforced cement.Since SiO_(2) coated on the surface of the modified CaSO_(4) whisker reacts with the free Ca(OH)_(2) in cement-based material,thus promoting the formation of more hydration products,such as calcium silicate hydrate gel chain(C-S-H),as well as makes the whiskers tightly wrapped by hydration products,thus enhancing the bonding effect between the whiskers and cement-based materials and causing more energy consumed during the development of crack.Also,the hydration reaction can improve the compactness of the cement structure,further enhancing the mechanical properties of cement.
作者
张博建
彭志刚
冯茜
邹长军
张健
ZHANG Bojian;PENG Zhigang;FENG Qian;ZOU Changjun;ZHANG Jian(School of Chemistry and Chemical Engineering,Southwest Petroleum University,Chengdu 610500,China;Drilling and Production Engineering Technology Research Institute of Chuanqing Drilling Engineering Co.,Ltd,Xi'an 710018,Shanxi,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2021年第10期2286-2297,共12页
Journal of The Chinese Ceramic Society
基金
四川省重点项目“四川盆地干热岩地热资源开发固井用高温水泥研究”(2019YJ0313)。
关键词
硫酸钙晶须
改性晶须
界面黏结性能
增强增韧
力学性能
calcium sulfate whisker
modified whisker
interfacial bonding performance
enhancement and toughening
mechanical properties
作者简介
第一作者:张博建(1993-),男,博士研究生;通信作者:彭志刚(1976-),男,博士,教授级高工。
