雄安站大截面异形墩柱清水混凝土施工技术

Fair-faced Concrete Construction Technology for Mass Special-shaped Concrete Pier Column in the Xiong'an Railway Station House

针对京雄城际雄安站房造型柱同时具备异形截面、大体积尺寸与清水外观的特点,本文通过试验研究与施工实践,利用混凝土配合比优化减少水化温升,并实时监测墩柱里表温差与保温养护措施降低墩柱开裂风险;优选聚羧酸减水剂提高混凝土工作性能,采用关键位点循环输送布料方式与精细化定点式振捣缓解混凝土落距高、振捣难的困境,提升墩柱复杂造型棱角处的成型质量.此外,提出钢筋、模板表面处理与表层保护防护等清水混凝土质量保障措施.

Specially designed column piers in waiting hall and corridor are with features of mass special-shaped in crosssection and fair-faced on concrete surface,which causes difficulties in construction.Based on experimental research and construction practice,results showed that:with optimization of concrete mix proportion,control measures of concrete entry temperature,real-time monitoring of concrete temperature change and using proper heat preservation measures,cracking risk of concrete was lowered with reduced temperature grads between inside and outside of column piers.Carefully selecting type of polycarboxylate superplasticizer to optimize workability and bubble elimination property,and circularly pumping concrete at some key positions instead of vertically pumping concrete at one fixed position into the mold,would ease concrete construction difficulties of high falling distance and inconvenience for vibration.In addition,precisely quality control of steel bar,mold surface and concrete shield treatment were also presented.