低温环境补偿收缩混凝土在桥面湿接缝的应用研究  

Research of shrinkage compensating concrete in wet joint construction of bridge deck in winter

作　　者：严帮伟 YAN Bangwei(Sixth China Railway 20th Bureau Group Corporation limited,Xi'an 710016,China)

机构地区：[1]中铁二十局集团第六工程有限公司,陕西西安710016

出　　处：《新型建筑材料》2024年第4期116-119,149,共5页New Building Materials

基　　金：陕西省渭南市科技重点研发项目(STYKJ2022-3);陕西省教育厅2023年度青年创新团队科学研究计划项目(23JP027)。

摘　　要：为解决钢-混组合桥梁湿接缝混凝土冬季施工时收缩徐变大、热量散失快、温度控制难等问题,设计了高强早强补偿收缩混凝土,采取控制混凝土原材料、混凝土拌制运输、浇筑和养护环节温度等措施,对钢-混组合桥桥面湿接缝混凝土冬季施工技术进行了研究。结果表明:膨胀剂掺量10%、早强剂掺量1.5%时,水中养护7 d限制膨胀率达3.6×10^(-4),14 d后转移至恒温恒湿养护室养护,28 d限制膨胀率达1.5×10^(-4),1 d抗压强度达到28 d的55%,28 d抗压强度为71.9 MPa,早期抗压强度高,能很好补偿混凝土的早期收缩。采取原材料保温加热、混凝土拌制运输和浇筑等过程保温,利用聚苯板和电热膜对翼缘板保温和加热,在混凝土表面覆盖薄膜、电热板加热,用棉被和双层篷布保温等措施能有效地促进混凝土的水化过程。In order to solve the problems of shrinkage,creep,heat loss and temperature control in wet joint concrete construction of steel-concrete composite bridge in winter,the high strength and early strength compensated shrinkage concrete was designed,the construction technology was studied by taking measures such as temperature control of raw materials,concrete during transportation,pouring process and curing process after pouring.The results show that expansion agent was 10%and early strength agent was 1.5%,the limited expansion rate reached 3.6×10^(-4) after curing in water for 7 d and 1.5×10^(-4) curing in curing room for 28 d,1 d strength was 55%of 28 d,28 d strength was 71.9 MPa.The early strength of concrete was high,early shrinkage of concrete can be well compensated.Temperature control measures included heating the materials,heat insulation during transportation and casting of concrete were preserved,the flange plate was insulated and heated by polystyrene plate and electrothermal film,the hydration process of concrete can be effectively promoted by covered with film,heated with electric heating plate,insulated with cotton quilt and double-layer tarpaulin.

关 键 词：高强补偿收缩混凝土 冬季施工 湿接缝 保温控制 

分 类 号：TU528[建筑科学—建筑技术科学]