氯盐环境下混凝土耐久性多因素模型的试验研究及统计分析

Multi-factors model for durability of concrete under chloride environment based on experimental and statistical analysis

为了准确评估混凝土的抗氯离子渗透性和耐久性,开展了不同矿物掺合料混凝土的制备和电通量测试,根据试验数据和文献数据分析了水胶比(水灰比)、粉煤灰掺量、矿渣掺量、硅灰掺量对混凝土电通量的影响,通过回归分析研究建立了混凝土电通量的多因素计算模型,通过对试验数据和文献数据的统计分析验证了该计算模型的正确性和广泛适用性。在此基础上,通过定量计算氯盐环境下混凝土结构服役寿命,分析了混凝土水胶比、掺合料组合及其掺量对混凝土耐久性的影响。结果表明,降低混凝土的水胶比、或提高掺合料掺量均能提高混凝土耐久性;使用矿物掺合料的高性能混凝土,其耐久性明显优于普通混凝土;矿渣对混凝土耐久性的改善优于粉煤灰;复合掺加粉煤灰和矿渣对提高混凝土结构耐久性的效果更加明显。

The charge passed through concrete is a key parameter for durability analysis of concrete under chloride environment. In this paper, the effect of the water/binder ratio, the replacements of fly ash, slag and silica fume on the charge passed is investigated by analyzing the experiment data and those collected from literatures, so that a multi-factor model is developed. The statistical analysis of data from literature and experiment demonstrates the satisfying accuracy and applicability of the model. The service life of reinforced concrete is studied based on Fick＇s second law and the multi-factors model, the results show that the reduction of water/binder ratio, or adding the content of blending admixtures can effectively improve the concrete service life. The concrete structures adding slag result in better durability than fly ash. The durability of high performance concrete （HPC） with both of fly ash and slag is better than those with fly ash or slag only.