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钢筋保护层处混凝土的氧气扩散速率是影响混凝土内钢筋锈蚀速率的重要因素.为确定保护层处混凝土氧气扩散速率,从多孔材料气体扩散的基本原理出发,根据Fick扩散定律并结合影响混凝土中氧气扩散速率的具体因素,建立了混凝土氧气扩散性能的预测模型,并通过试验对模型进行了验证.试验表明预测模型的计算结果和试验测试结果基本一致;混凝土氧气扩散系数随混凝土孔隙率、环境温度和相对湿度的增高而增大,在温湿度条件不变的情况下,混凝土孔隙率由0.09增大到0.18时,混凝土氧气扩散系数约增大4倍.
The diffusion rate of oxygen in the concrete at the steel reinforcement layer is an important factor that affects the corrosion rate of steel in the concrete.In order to determine the oxygen diffusion rate of concrete in the protective layer, based on the basic principle of gas diffusion in porous materials, according to the Fick diffusion law and the influence of oxygen The diffusion coefficient and the diffusion rate of the concrete, the prediction model of oxygen diffusivity in concrete is set up, and the model is validated through experiments.The results show that the calculated results of the prediction model and the test results are basically the same.The concrete oxygen diffusivity varies with the porosity of concrete, ambient temperature And the relative humidity increases. Under the conditions of constant temperature and humidity, when the porosity of concrete increases from 0.09 to 0.18, the oxygen diffusion coefficient of concrete increases about 4 times.