摘要
冻融循环与盐侵蚀严重威胁水泥混凝土结构的耐久性能,使用高性能水泥基修补材料可以有效减少病害、降低修补频次。本文系统总结了国内外盐冻循环条件下水泥基修补材料的损伤机理及性能优化的研究进展,揭示了氯盐与硫酸盐耦合侵蚀下多尺度破坏机制,阐明了孔隙结构演变、离子迁移规律及化学-物理耦合损伤过程。基于宏观和微观分析,提出了通过复合掺合料、纳米材料及化学外加剂的耦合改性策略,显著提升了材料的抗盐冻性能与界面相容性。研究表明:掺入硅灰(5%~10%)、引气剂(0.02%~0.03%)及氧化石墨烯(0.06 wt%)可细化孔隙结构,抑制冰结膨胀与盐结晶压力;碳纳米管与纤维增强技术可通过桥联作用延缓微裂纹扩展,使修补材料经1500次盐冻循环后强度损失率降低至5%以下。以上措施可为高抗盐冻水泥基修补材料的研发提供理论依据与技术路径,对延长寒冷地区工程结构的寿命具有重要指导意义。
Freeze-thaw cycles and salt erosion seriously threaten the durability of cement concrete structures,and the application of high-performance cement-based repair materials can effectively delay the damage and reduce the repair frequency.This paper systematically summarises the research progress on the damage mechanism and performance optimisation of cement-based repair materials under the conditions of salt-freezing cycles at home and abroad,reveals the multi-scale damage mechanism under the coupled erosion of chloride and sulphate,and elucidates the evolution of the pore structure,the ionic migration law and the chemical-physical coupling damage process.Based on the macroscopic and microscopic analyses,a coupled modification strategy through composite dopants,nanomaterials and chemical admixtures is proposed to significantly enhance the salt-freezing resistance and interfacial compatibility of the materials.The researches show that the incorporation of silica fume(5%~10%),air-entraining agent(0.02%~0.03%)and graphene oxide(0.06 wt.%)can refine the pore structure and inhibit the expansion of icing and salt crystallisation pressure;carbon nanotubes and fibre reinforcement technology retard the expansion of microcracks through the bridging linkage effect,so that the loss of strength rate of the repair material is reduced to less than 5%after 1,500 salt-freezing cycles.The aforementioned measures provide a theoretical basis and technical path for the research and development of high salt-freeze-resistant cement-based repair materials,which is of great significance in extending the life of engineering structures in cold regions.
出处
《混凝土世界》
2025年第6期59-67,共9页
China Concrete
基金
河北省创新能力提升计划项目科技研发平台专项(24461501D)。
关键词
水泥基修补材料
盐冻循环
化学改性
纳米材料
耐久性能
Cement-based repair materials
salt-freezing cycles
chemical modification
nanomaterials
durability
