海洋潮汐浪溅区混凝土表面氯离子浓度的改进计算模型

收集世界不同地区304组海洋潮汐浪溅区自然暴露混凝土的试验数据,据此分析水胶比、胶凝材料种类和暴露时间对混凝土表面氯离子浓度C_(s,ts)的影响规律,进而结合二阶段多元非线性回归分析,分别确定了硅酸盐水泥、粉煤灰、矿渣和硅灰等胶凝材料对C_(s,ts)的修正系数,建立了海洋潮汐浪溅区C_(s,ts)的改进模型,并利用现有模型和试验数据对比,验证了该模型的适用性。分析表明:C_(s,ts)与水胶比之间近似呈线性关系,且胶凝材料种类对C_(s,ts)的影响显著;C_(s,ts)在前5a内快速增长,随后逐渐趋于稳定,可以利用指数型函数来描述其时变规律。

Improved model for surface chloride concentration of concrete in marine tidal and splash zones

The influences of water-to-binder ratio, binder type and exposure time on the surface chloride concentration C_s,ts of concrete exposed to marine tidal and splash zones were investigated systematically in this study based on 304 sets of field test data selected from different sites around the world. Then, the correction factors of four binder types can be determined using the two-phase multiple nonlinear regression technique, including the ordinary Portland cement, fly ash, slag and silica fume. Finally, an improved model for C_s,ts was developed. The applicability of the improved model for C_s,ts was validated in comparison with existing models and field test data. Analysis results show that the surface chloride concentration increases linearly with water-binder-ratio, while the influence of binder type on C_s,ts cannot be ignored. Moreover, C_s,ts increases over exposure time exponentially, which appears a fast increase in the first 5 years and then becomes constant.