大芦线钢管自密实混凝土的配制与应用

针对大芦线jj公路桥大跨度钢管拱的特点，在自密实混凝土配制思路的基础上，通过水胶比调整、胶凝体系优化、外加剂改进、掺适量膨胀剂等几方面技术的相互结合，采用优选骨料，配制超长工作性、微膨胀、高早强的自密实混凝土。经检测，钢管自密实混凝土在6小时内保持有良好的工作性，7天强度在C50的80％以上，14天限制膨胀率为1．6×10-4，28天限制收缩率为2．0×10-4，具有微膨胀的性能，满足施工及设计要求，在大芦线桥梁工程中取得了较好的应用效果。

Preparation and Application of Serf-Compact Concrete Filled Steel Tube Structure in Da-Lu Line Engineering

Abstract： As for the characters of steel tube structure in Da-Lu Line long-span bridge, to consult the experience of self-compact concrete, adopt technologies of adjustment of water-binder ratio, optimization of cementations system, improvement of admixture, and doping proper amount expansive agent, to prepare a kind of self-compact concrete with super-long workability, slight-expansion and high early strength. Self-compact concrete filled steel tube structure maintained good workability in 6h, and got 80% strength of C50 at 7th day, meanwhile with slight-expansion （ restrained-expansion rate at 14th day was 1.6＊10-4and restrained- shrinkage rate at 28th day was 2.0＊ 10-4）, which satisfied the requirements of construction and design, and it got good application effects in t Da-Lu Line engineering.