大管桩现场取样分析与耐久性研究

采用现场取样与室内化学分析相结合的方法,研究海洋环境下大管桩的耐久性能。通过对深圳、连云港和宁波3个地区服役1~17 a的大管桩展开耐久性调查,同时在潮差区和浪溅区的桩身混凝土钻芯取样,采用化学分析的方法测试不同深度混凝土中的氯离子含量,计算混凝土氯离子扩散系数,进而经统计分析得出桩身混凝土的腐蚀参数。通过对比研究桩身混凝土与桩帽节点混凝土的抗氯离子渗透性能的差异,研究裂缝对氯离子渗透的影响及大管桩接头处FRP包覆层对接头耐久性的影响。取样研究过程中未发现任何箍筋和主筋锈蚀的现象,服役10~15 a的大管桩箍筋表面氯离子浓度在0.1%~0.2%,箍筋表面光洁如新。

Field Sampling, Analysis and Research on Durability of Large Diameter Cylindrical Piles

The durability of large diameter cylindrical piles under marine environment is studied by field sampling and chemical analysis in laboratory.To investigate the durability of large diameter cylindrical piles which have been in service for 1 to 17 years in Shenzhen,Lianyungang and Ningbo,samples were taken from the large diameter cylindrical piles in the tidal zone and the splash zone,the chloride content at different depth is analyzed,the chloride diffusion coefficient is calculated and the corrosive parameters of concrete are obtained by statistical analysis.Moreover,the difference of chloride percolation capacity between the pile and the pile cap is compared and the influence of cracking on chloride penetration and that of the FRP clad on the durability of pile joints are also investigated.No sign of rusting in the stirrup reinforcement and the principal reinforcement is found in the study and the chloride concentration at the surface of the stirrups in the piles which have been in service for 10 to 15 years is 0.1%-0.2% and the surface of the stirrups are brand new.