黄土高原地区薄壁空心高墩严寒期蒸汽养护施工技术

延延高速陕晋交界的黄河特大桥墩高141 m,是陕西省跨黄河连续刚构桥的第一高墩,桥址在黄土高原地区,冬季黄河河道气温在-20℃以下。通过介绍对采用液压爬模的薄壁空心高墩进行蒸汽养护的现场具体实施过程,论述了耐久性C50混凝土的冻害、一些抗冻要求以及防冻害措施,介绍了混凝土运输、拌和过程中温度的控制方法,以及现场蒸汽养护的施工工艺,使C50耐久性砼在低温下快速达到设计强度,确保施工质量,又能满足施工工期需要,为其他相类似的工程提供可参考的依据。

Steam Curing Construction Technology for Hollow Thin-walled High Pier in Loess Plateau Area During Cold Period

Super high piers for the Huanghe River bridge,141 m in height,on Yan’an-Yanchuan high-speed at the junc-tion of Shanxi and Shaanxi provinces,is the highest pier for continuous rigid frame bridge over the Huanghe River in Shaanxi province.The bridge is located in Loess Plateau area with winter temperature along the Huanghe River below-20 ℃.The paper introduces the specific process of steam curing of hollow thin-walled high pier with the hydraulic climb-ing formwork and explores the freezing problems of high strength concrete C50,some antifreezing requirement and counter-measures.It introduces the temperature control method for concrete transportation,the mixing as well as the steam curing construction technology on field.The durability of C50 concrete quickly reaches the design strength at low temperatures, which ensures the construction quality,and can meet the need of construction period.Thus,provides reference for other similar engineering.