干海子大桥钢管混凝土设计制备与性能研究

Formation design and performance of concrete filled steel tube applied in Ganhaizi bridge

根据干海子大桥冬期混凝土施工要求和现场原材料特性,采用亚硝酸钠与乙二醇形成有机、无机协同防冻,设计制备出流动性好、包裹性佳、自密实的抗冻钢管混凝土。并通过现场实验,结合SEM观测,研究了其在低温浇筑与养护、后期升温后强度的发展规律。结果表明,低温条件成型的钢管混凝土短柱与核心混凝土试件,早期强度发展较好,后期温度回升后强度能稳定增长。设计制备的钢管混凝土具有很好的低温工作性能和力学性能,抗冻性能优越,能满足依托工程冬季钢管混凝土施工质量要求。

According to winter concrete construction requirements and raw materials properties of Ganhaizi bridge,sodium nitrite and ethylene glycol were used to form organic and inorganic coordination antifreeze,frost resistance core concrete with outstanding package,excellent fluidity and good self-compacting ability was pre-pared.The laws of later strength evolution of concrete filled steel tube which pouring and maintenance at low temperature were investigated.Scanning electron microscope (SEM)was used to analyze the micro-morphology features of core concrete.It was confirmed that core concrete and concrete filled steel tube short column which manufactured at the low-temperature have a high early strength,and the later strength would steady grow when the temperature rise.The concrete prepared have prominent working performance and mechanical properties at low temperature,and good frost resistance,which would meet the winter concrete construction requirements of Ganhaizi bridge.