隧洞混凝土力学性能与耐久性能影响因素研究

Study on Influencing Factors of Mechanical Properties and Durability of Tunnel Concrete

优质矿物掺合料的使用及良好的混凝土和易性可以避免结构出现漏筋及强度偏低的问题。结合某水电站引水隧洞混凝土施工结构后表面存在的漏筋及其实体回弹强度偏低等问题,优化混凝土原材料配合比,改善混凝土和易性。结果表明:当矿粉掺量达到30%、粉煤灰掺量达到25%时,可以显著改善混凝土后期强度偏低的问题;当混凝土倒筒时间达到3.2s,初始扩展度达到600mm,U型箱高度差达到0mm时,混凝土和易性良好,易于施工,实体表面平整光滑,无漏筋。

The use of high quality mineral admixtures and good concrete workability can avoid the problems of leakage of reinforcement and low strength of the structure.Combined with the problems of reinforcement leakage and low rebound strength of concrete structure after construction of the diversion tunnel of a hydropower station,the mix ratio of concrete raw materials was optimized to improve the workability of concrete.The results show that when the ore powder content reaches 30%and the fly ash content reaches 25%,the problem of low strength of concrete in later period can be significantly improved;when the concrete inverted drum time reaches 3.2s,the initial expansion reaches 600mm,and the U-shaped box height difference reaches 0mm,the concrete workability is good,easy to construct,the solid surface is smooth,and there is no leakage of reinforcement.