崇启大桥承台混凝土配合比设计及性能研究  

Mix Proportioning Design and Performance Study of Pile Cap Concrete of Chongqi Bridge

作　　者：秦鸿根[1] 王伦[1] 庞超明[1] 周建林 

机构地区：[1]东南大学材料科学与工程系江苏省土木工程材料重点实验室,江苏南京211189 [2]江苏省崇启大桥建设现场指挥部,江苏启东226600

出　　处：《世界桥梁》2011年第4期57-60,共4页World Bridges

基　　金：973计划资助项目(2009CB623200)

摘　　要：为提高江海交汇环境下大型桥梁承台混凝土的耐久性，试验测试崇启大桥承台混凝土的基本力学性能、变形性能、氯离子扩散系数和相应胶凝材料的水化热等。研究表明，优化后的配合比混凝土基本力学性能满足设计要求；掺40％～60％矿物掺合料的混凝土28d干燥收缩率为（1．4～2．5）×10^-4，到120d趋于稳定；氯离子扩散系数随龄期的增长和掺合料的增加而降低，双掺组为单掺组的20％～30％；大掺量矿物掺合料胶凝材料的7d水化热相对未掺组降低了30％。通过优选，确定粉煤灰掺量40％、矿粉掺量20％配合比为该桥承台混凝土配合比。To enhance the durability of the concrete for the pile caps in the confluent environment, the basic mechanical behavior, deformation behavior, chlorine diffusion coefficient and hydration heat of the corresponding binder of the concrete used in the pile caps of the Chongqi Bridge have been tested and studied. The results of the study show that the basic mechanical behavior of the concrete after its mix proportioning is optimized can meet the design requirements, the dry shrinkage ratio of the concrete added with 40%-60% of mineral admixture at 28 d is （1. 4-2.5） × 10^-4 and the shrinkage ratio tends to be stable at 120d. The chlorine diffusion coefficient decreases with the increase of concrete age and adding amount of the admixture and the coefficient of the specimen groups with double admixture is 20%-30% of the specimen groups with single admixture. In comparison to the specimen groups without admixture, the hydration heat of the binder added with great amount of mineral admixture at 7 d decreases 30%. By optimal selection, it is determined that the mix proportioning with 40% fly ash and 20% mineral admixture should be the mix proportioning of the concrete for the pile caps of the bridge.

关 键 词：桥梁 承台 混凝土 力学性能 变形性能 氯离子扩散系数 水化热 试验 研究 

分 类 号：U443.25[建筑科学—桥梁与隧道工程] TU528[交通运输工程—道路与铁道工程]