全断面浇筑沉管低热低收缩高性能混凝土配制及优选

Preparation and optimization of high performance concrete with low heat and low shrinkage for full-face casting immersed tube

通针对港珠澳大桥沉管混凝土高工作性、高强度、高抗裂性以及长寿命等要求,采用混掺大掺量粉煤灰与矿渣粉胶凝材料体系配制低热、低收缩的沉管混凝土。通过配合比组成因素对混凝土工作性、强度、耐久性以及抗裂性影响的分析,结合混凝土温度应力测试以及抗裂安全系数计算,优选出满足沉管各项性能要求且具备最佳抗裂性能的低热低收缩高性能混凝土配合比,并在港珠澳大桥沉管预制中得到应用,成功避免了沉管节段早期危害性裂缝的产生。

For the sake of high workability, high strength, high crack resistance and long service life of immersed tube concrete for Hung Kong-Zhuhai-Macao Bridge, the immersed tube concrete which were low hydration heat and low shrinkage had been mixed with large amount of fly ash and slag powder.Influences of mix proportion parameters on workability, strength, durability and crack resistance were analyzed.The high performance concrete mix proportion of low hydration heat and low shrinkage was been optimization and satisfied with performance requirements of immersed tube.As the use of the optimum mix proportion,the harmful early crack was successfully avoided during precast immersed tubes.