微波照射单骨料混凝土的多场耦合机理研究

Study on Multi-Field Coupling Mechanism of Single Aggregate Concrete Irradiated by Microwave

摘要: 为探索固废回收新方向，提高微波对混凝土破碎及骨料界面分离的效果，阐释微波照射混凝土的电磁–热–力多场耦合效应，本文将利用COMSOL Multiphysics软件，对微波照射下混凝土多场耦合力学机理进行研究。基于单骨料混凝土进行微波照射下的多场耦合研究，主要从电场、温度场、应力场三方面阐释多场耦合机理。结果表明：电场强度和温度梯度在砂浆–骨料界面处达到最大值；骨料内部受拉受压状态同时存在，界面过渡区和砂浆区域受压，第一主应力超过砂浆的极限抗拉强度，出现损伤，随着照射时间的增加或输入功率的上升，损伤会逐渐加大，最终导致砂浆与骨料在界面处发生分离。本研究可为微波照射下的砂浆–骨料界面分离提供一定的参考。

Abstract: In order to explore the new direction of solid waste recovery, improve the effect of microwave on concrete crushing and aggregate interface separation, and explain the electromagnetic, thermal and force multi-field coupling effect of microwave irradiation on concrete, this paper will use COMSOL Multiphysics software to study the multi-field coupling mechanical mechanism of concrete under microwave irradiation. Based on the study of multi-field coupling under microwave irradiation of single aggregate concrete, the multi-field coupling mechanism is explained from three aspects: electric field, temperature field and stress field. The results show that the electric field intensity and temperature gradient reach the maximum value at the mortar-aggregate interface. The tension and compression state inside the aggregate exists simultaneously, the interface transition zone and the mortar area are compressed, and the first principal stress exceeds the ultimate tensile strength of the mortar, resulting in damage. With the increase of irradiation time or the rise of input power, the damage will gradually increase, and finally lead to the separation of mortar and aggregate at the interface. This study can provide some reference for the interfacial separation of mortar and aggregate under microwave irradiation.