摘要
滨海地区钢筋混凝土结构受海水腐蚀破坏的风险较大,明确骨料对混凝土抗氯盐侵蚀性能的影响对指导项目骨料选材与混凝土配合比调控具有重要参考意义。本工作选取了塞内加尔地区某滨海公路项目现场的两种碎石粗骨料,利用图像分析表征了骨料的粒形,设计了不同的骨料级配,采用电通量、快速氯离子迁移系数(RCM)、浸泡等方法表征了混凝土的抗氯盐侵蚀性能,利用CPM模型计算了不同粒形、级配骨料的堆积密度,并探讨了骨料堆积密度对混凝土抗氯盐性能的影响。结果表明,与自然浸泡相比,电场加速方法(RCM、电通量)低估了级配、粒形的影响。在抗氯盐侵蚀混凝土骨料级配设计时,需要兼顾增大骨料的堆积密度及减小骨料的总比表面积。较差的骨料粒形会进一步减小骨料堆积密度,增大骨料总比表面积,形成更多的界面过渡区,对混凝土抗氯盐侵蚀性能起劣化作用。
Reinforced concrete structures in coastal regions face significant risks of damage from seawater corrosion.Clarifying the influence of aggregate on the chloride resistance of concrete holds important reference significance for guiding aggregate selection and concrete mix proportion control in projects.Two types of coarse aggregates from the site of a coastal highway project in the Senegal region were selected for this study.Aggregate particle shape was characterized using image analysis and different aggregate gradations were designed.The chloride resistance of the concrete was characterized using methods including Coulomb electric flux,RCM,and immersion test.Finally,the CPM model was employed to calculate the packing density of aggregates with different particle shapes and gradations,and the influence of aggregate packing density on the chloride resistance of concrete was investigated.The results indicate that,compared to the immersion test,electrically accelerated test methods may underestimate the effects of gradation and particle shape.When designing aggregate gradation for chloride-resistant concrete,it is essential to balance the objectives of increasing aggregate packing density and reducing the total specific surface area of the aggregates.Poor aggregate particle shape further reduces aggregate packing density,increases the total specific surface area,leading to the formation of more interfacial transition zones,thereby impairing the concrete's resistance to chloride ion penetration.
作者
汪伟
李嘉民
范志宏
杨海成
WANG Wei;LI Jiamin;FAN Zhihong;YANG Haicheng(Key Laboratory of Harbor&Marine Structure Durability Technology of Transport Industry,CCCC Fourth Harbor Engineering Institute Co.,Ltd.,Guangzhou 510230,China;Key Laboratory of Construction Material,CCCC,Guangzhou 510230,China)
出处
《材料导报》
北大核心
2025年第S2期159-164,共6页
Materials Reports
基金
中交集团青年创新项目(2023-ZJKJ-QNCX03)。
关键词
骨料级配
骨料粒形
抗氯盐侵蚀性能
骨料堆积密度
氯离子扩散系数
aggregate gradation
aggregate particle shape
chloride resistance
aggregate packing density
chloride diffusion coefficient
