海洋环境下钢纤维-超高性能混凝土界面粘结性能劣化机理  

Interfacial Bonding Deterioration Mechanism of Steel Fiber-Ultra High Performance Concrete in Marine Environment

作　　者：李柯璇 毛金旺 刘铁军 周傲 LI Kexuan;MAO Jinwang;LIU Tiejun;ZHOU Ao(Guangdong Provincial Key Laboratory of Intelligent and Resilient Structures for Civil Engineering,Harbin Institute of Technology,Shenzhen 518055,Guangdong,China)

机构地区：[1]哈尔滨工业大学(深圳),广东省土木工程智能韧性结构重点实验室,广东深圳518055

出　　处：《硅酸盐学报》2024年第11期3418-3430,共13页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金项目(52025081,U23A20658,52379121)。

摘　　要：海洋严酷环境下钢纤维与水泥基体的界面粘结性能对超高性能混凝土(UHPC)的力学及耐久性能至关重要。然而,目前海洋环境下钢纤维-水泥基体界面劣化机理尚不明确,且缺乏改善界面粘结性能有效的方法。采用分子动力学和钢纤维拔出试验,探究了海洋氯盐环境下硅烷偶联剂(SCA)改性前后钢纤维-水泥基体界面粘结性能的退化规律;结合界面区键合网络演化及溶液离子运动特性,揭示了海洋氯盐环境下SCA改性前后钢纤维-基体界面粘结性能劣化机理。结果表明:海洋氯盐环境下水分子和侵蚀离子会破坏钢纤维与水泥基体间的氢键连接,削弱界面的粘结性能;而SCA改性能增强钢纤维与基体间的氢键成键能力,增加界面接触面积,提高了界面过渡区的密实度,保障了界面完整性;SCA改性促使钢纤维与水泥基体间形成稳定的物理氢键网络及化学键合(硅酸盐链的交联)连接,增强了界面粘结性能,提高了界面在海洋严酷环境下的耐蚀性。本工作揭示了海洋氯盐环境下钢纤维-水泥基体界面的劣化机理,为优化和调控UHPC在海洋严酷环境下的耐久性提供了理论基础和方法支撑。Introduction The interfacial bonding properties between steel fibers and cementitious matrix under harsh marine environment are crucial for the mechanical properties and durability of UHPC.However,studies on the deterioration mechanism of the steel fiber-cementitious matrix interface in marine environments are insufficient.There is a lack of effective approaches to improve the interfacial bonding properties.This study provides novel approach to strengthen the interfacial transition zone and enhance the interfacial bonding properties using silane coupling agent(SCA).Based on molecular dynamics simulation and steel fiber pull-out test,the variation rules of bonding performance and debonding strength of steel fiber-matrix interface in UHPC under harsh marine environment were clarified.The microstructural variation,bonding network evolution and bonding trend of interfacial chemical bonds for the pristine and SCA-modified interfaces in the harsh marine environment were investigated.Based on this,the interfacial bonding degradation mechanism of the pristine and modified interfaces under marine chloride environment was revealed.This study is expected to provide theoretical basis and methodological support for optimizing and regulating the durability of UHPC in harsh marine environment.Methods Based on molecular dynamics simulation,the variation of interfacial interaction energy and initial contact area before and after SCA modification in the harsh marine environment was calculated and the images of interfacial configurations in the marine environment were captured.Using interface debonding simulation and steel fiber pull-out experiments,the load-displacement curves and interfacial fracture energy pristine and SCA-modified interfaces were investigated during the debonding process in the marine environment.Microscopic morphology of interfacial transition zones in the marine environment was observed by scanning electron microscopy(SEM)and backscattered electron imaging(BSE).Moreover,molecular dynamics simulation was used

关 键 词：海洋氯盐环境 硅烷偶联剂 钢纤维-水泥基体界面 劣化机理 分子动力学 

分 类 号：TU528.572[建筑科学—建筑技术科学]