To evaluate the radiation-induced degradation of concrete, a rigid-body spring network model is introduced that takes into account the three phases in concrete: mortar, aggregate, and the interfacial transition zone. The proposed model enables evaluation of the change in the physical properties of concrete affected by aggregate expansion under the free restraint condition. Good agreement with previous experimental data is found for the linear expansion of the concrete specimen and the compressive strength, Young’s modulus, and splitting tensile strength. Based on the numerical results, it is concluded that, to reproduce the physical property changes in concrete, the expansion of mortar due to the radiation-induced expansion of fine aggregate and/or creep behavior must be considered. In addition, it is clarified that an isolated expansion of mortar with a lack of expansion in the coarse aggregate also degrades the concrete and, consequently, analysis of the type of aggregate used is critical for predicting the properties of concrete under neutron irradiation. Furthermore, the impact of inhomogeneous expansion of rock-forming minerals in coarse aggregates on physical property changes is studied, showing that such a partial expansion in the aggregates and the resultant cracks in aggregates greatly influences the reduction of the Young’s modulus, with minimal impact on the reduction of compressive strength. The proposed model can be used to evaluate concrete degradation due to radiation-induced volumetric expansion of aggregate caused by the metamictization of rock-forming minerals.

为了评估辐射引起的混凝土降解，引入了刚体弹簧网络模型，该模型考虑了混凝土中的三个阶段：砂浆，骨料和界面过渡区。所提出的模型能够评估在自由约束条件下受集料膨胀影响的混凝土的物理性能变化。在混凝土试样的线性膨胀，抗压强度，杨氏模量和劈裂抗拉强度方面，与先前的实验数据吻合良好。基于数值结果，得出的结论是，为了再现混凝土的物理性能变化，必须考虑由于辐射引起的细骨料膨胀和/或蠕变行为而引起的砂浆膨胀。此外，明确的是，孤立的砂浆膨胀在粗骨料中缺乏膨胀也会使混凝土降解，因此，分析所用骨料的类型对于预测中子辐照下混凝土的性能至关重要。此外，研究了粗骨料中成岩矿物非均质膨胀对物理性质变化的影响，表明骨料中的这种局部膨胀以及骨料中产生的裂纹极大地影响了杨氏模量的降低，对杨氏模量的影响最小。压缩强度的降低。所提出的模型可用于评估由于成岩矿物的成矿作用引起的辐射诱导的骨料体积膨胀而引起的混凝土退化。