大跨度细管径薄壁钢管拱桥混凝土配合比设计与施工

Proportion Design and Construction for Steel Tube-confined Concrete Arched Bridge with Great Span and Small Diameter Tube

浙江南浦大桥为典型的大跨度、细管径薄壁钢管混凝土拱桥,其钢管混凝土施工采用泵送顶升法,施工难度大,对混凝土性能要求高.经混凝土配合比设计与优化,制备出满足设计要求的C50微膨胀钢管混凝土,并进行混凝土的拌合物性能、物理力学性能及微观结构分析研究.结果表明,所配制的混凝土不离析、不泌水,初始坍落度23 cm,扩展度不小于60 cm,混凝土拌和物3 h后的坍落度不小于18 cm,混凝土具有早强、高弹性模量和补偿收缩等性能,完全满足浙江南浦钢管混凝土拱桥的工程设计及施工要求.

The Zhejiang Nanpu Bridge belongs to the typical steel tube-confined concrete arched bridge with great span and small diameter steel tube, and the concrete-pumping technology was applied to its building with strict properties requirements of steel tube-confine concrete. In this paper, the pumped C50 steel tube -confined concrete with micro expansion was prepared through design and optimization of concrete proportions, workability, mechanical properties as well as the microscopic structure were researched too. The results show that the concrete prepared not only has a perfect workability, which fresh slump hits 23 cm and remains 18 cm after 3 h while its fresh flow is more than 60 cm, but also has a compensating shrinkage performance, highly early strength and high elastic modulus to meet the needs of engineering requirements of the Zhejiang Nanpu steel tube-confined concrete arched bridge.