微波加热与传统加热下混凝土的热力学响应

传统混凝土破碎技术存在粗骨料损伤大、机械磨损严重和能耗高等弊端，这些问题可以通过在破碎前对混凝土进行微波处理来解决。为了评价微波处理技术的工业适用性，通过不同功率微波对混凝土试件进行加热，并与传统加热方式相比较，研究混凝土的加热效率和宏观裂纹扩展规律，而后进行单轴抗压强度试验，得到混凝土在不同热处理条件下的强度弱化规律。结果表明：与传统加热方式相比，微波加热技术能有效促进混凝土内部和表面裂纹扩展，削弱混凝土的强度，并且高功率微波下效率更高，能量消耗更少。此外，微波加热时未完全烘干的混凝土容易出现低温爆裂现象，爆裂时间与功率水平呈负幂函数关系，与烘干时间呈正幂函数关系。

Thermodynamic response of concrete under microwave heating and conventional heating

Traditional concrete crushing technology has the disadvantages such as large damage of coarse aggregates, serious mechanical wear and high energy consumption. These problems can be solved by microwave treatment of concrete before crushing. To evaluate industrial applicability of this technology, concrete specimens were heated by different microwave power, and compared with conventional heating method, the heating efficiency and macro-crack propagation mechanism of concrete were investigated. Then the uniaxial compressive strength test was carried out to obtain the strength weakening law of concrete under different heat treatment conditions. The results illustrate that compared with the conventional heating method, microwave heating technology can effectively promote the internal and surface crack propagation of concrete, thus reducing the strength of concrete, and has higher efficiency and less energy consumption under high microwave input power. Besides, the results show that the concrete which is not completely dried is easy to burst at low temperature under microwave heating, and the relationship between burst time and power level is a negative power function, and the relationship between burst time and drying time is a positive power function.