核电厂预应力混凝土安全壳中氯离子扩散系数的预测方法EI北大核心CSCD

氯离子扩散系数是评价沿海环境中核电厂预应力混凝土安全壳耐久性的重要参数。该文基于两尺度方法,通过分析双轴等压下水泥浆基体、界面和混凝土细观结构,建立了水泥浆基体和界面毛细孔隙率与预应力之间的定量关系。为了量化预应力对微裂纹闭合、产生和扩展的影响,提出了临界毛细孔隙率与预应力之间的经验公式。将混凝土模拟成由骨料、界面和水泥浆基体组成的三相复合材料,获得预应力混凝土氯离子扩散系数比。通过与试验结果比较,校正了经验公式中的两个参数。用三组试验数据初步验证了该预测方法的有效性。

A PREDICTION METHOD FOR THE CHLORIDE DIFFUSIVITY IN PRESTRESSED CONCRETE CONTAINMENT VESSELS IN NUCLEAR POWER PLANTS

Chloride diffusivity is an important parameter for assessing the durability of prestressed concrete containment vessels in nuclear power plants located in a marine environment. Based on a two-scale method, a quantitative relationship between the capillary porosities of cement paste matrix and interfacial transition zone (ITZ), and the prestress is established by analyzing the mesostructures of cement paste matrix, ITZ and concrete under an equi-biaxial compression. To quantify the effect of prestress on the closure, initiation and extension of microcracks, an empirical formula between the critical capillary porosity and the prestress is proposed. Concrete is then modeled as a three-phase composite material, composed of aggregate, ITZ and cement paste matrix, and the chloride diffusivity ratio of concrete is obtained. Through comparison with experimental results, two parameters in the empirical formula are calibrated. The validity of the prediction method is preliminarily verified with three sets of experimental data.