海砂UHPC水化微结构演变及其固氯作用  

Evolution of sea-sand UHPC hydration microstructure and its chloride binding effects

作　　者：韦建刚[1,2] 陈荣 黄伟[1,3] 卞学海 陈宝春 Wei Jiangang;Chen Rong;Huang Wei;Bian Xuehai;Chen Baochun(College of Civil Engineering,Fuzhou University,Fuzhou 350116,China;College of Civil Engineering,Fujian University of Technology,Fuzhou 350108,China;Lets Holding Group Co.,Ltd.,Xiamen 361004,China)

机构地区：[1]福州大学土木工程学院,福州350116 [2]福建工程学院土木工程学院,福州350108 [3]垒知控股集团股份有限公司,厦门361004

出　　处：《东南大学学报（自然科学版）》2022年第1期90-99,共10页Journal of Southeast University：Natural Science Edition

基　　金：中国博士后科学基金资助项目(2020M671951);福建省中青年教师教育科研资助项目(JAT200012);高性能土木工程材料国家重点实验室开放基金资助项目(2019CEM003).

摘　　要：为了探明海砂作为细骨料对超高性能混凝土(UHPC)水化与微结构演变机理的影响,采用不同氯离子含量的模拟海砂制备UHPC,通过水化热、X射线衍射、基体氯离子含量和pH含量测定、扫描电镜、能谱分析以及氮气吸脱附研究了海砂UHPC基体内部微环境的演变.结果表明:海砂UHPC水化进程随着氯离子含量的增加而增加;在3 d龄期时基体内未生成Friedel盐,而是在28 d时生成;海砂UHPC对氯离子结合作用主要发生在7 d前,且随着氯离子含量增大而降低;基体pH值在水化14 d后随氯离子含量的增大而减小,并在28 d时趋于稳定;海砂的掺入在早期能够细化2~10 nm的孔径,但在后期与不含氯盐的UHPC总孔隙率相差无异.研究结果可为海砂UHPC具有优异的力学性能和护筋性能提供理论依据.To explore the effects of sea-sand as fine aggregate on the hydration and microstructure evolution mechanism of ultra-high performance concrete(UHPC),UHPC was prepared with simulated sea-sand with different chloride ion contents.The evolution of micro-environment in UHPC matrix of sea-sand was studied by isothermal conduction calorimetry,X-ray diffraction,determination test of chloride ion content and pH content in matrix,scanning electron microscopy,energy spectrum analysis,and nitrogen adsorption and desorption.The results show that the hydration process of UHPC increases with the increase of the chloride ion content.The Friedel salt is not formed in the matrix at 3 d,but at 28 d.The chloride binding behavior of sea-sand UHPC mainly occurs before 7 d.The capacity of the UHPC to bind chloride ions decreases with the increase of the chloride ion content.The pH value of the matrix decreases with the increase of the chloride ion content after hydration for 14 d,and is gradually stable at 28 d.The incorporation of sea-sand can refine the pore size of 2 to 10 nm in the early stage,but the total porosity of UHPC is no different from that of the chlorine-free UHPC in the later stage.The results provide a theoretical basis for the excellent mechanical properties and the reinforcement protection property of sea-sand UHPC.

关 键 词：海砂 超高性能混凝土 氯离子 水化 微结构 

分 类 号：TU528[建筑科学—建筑技术科学]