Concrete impact failure can occur quickly and cause severe failure, which is of great significance for effective monitoring of concrete impact failure. Infrared thermal imaging technology possesses the merits of high sensitivity, noncontact, and nondestructive monitoring, rendering it extensively employed in monitoring the stability of concrete structures. However, the infrared radiation temperature (IRT) evolution law and thermal effect mechanism of concrete impact failure are not clear at present. In this study, infrared monitoring experiments were conducted on concrete impact failure and static load failure using drop hammer (DH) testing machines, pressure testing machines, and infrared thermal imagers. The infrared thermal images and the IRT change law of concrete subjected to DH impact failure were analysed. The infrared thermal effect difference and mechanism between DH impact and static load failure were compared. The results indicate that there is an infrared high-temperature point at the impact location of concrete DH impact failure, and both average infrared radiation temperature (AIRT) and maximum infrared radiation temperature (MIRT) increase suddenly. The increase in the MIRT is tens of times that of the AIRT. Compared with that of static load failure, the infrared high-temperature area of concrete DH impact failure is concentrated, while the IRT of static load failure increases overall, and the heating area is large. Moreover, the change in the IRT under DH impact failure is much greater than that under static load failure. The infrared thermal effect of concrete under DH impact failure was mainly composed of the thermoelastic effect, frictional thermal effect and tensile failure endothermic effect. The infrared data obtained for concrete impact failure should focus on the highest and lowest IRT change indicators. The highest IRT corresponds to the impact failure point, and the lowest IRT corresponds to the tensile failure position. The research results provide a new infrared thermal effect approach for monitoring the stability of concrete under impact failure.

中文翻译：

---

混凝土冲击破坏红外温度演化规律及热效应机制

混凝土冲击破坏能够迅速发生并造成严重破坏，对混凝土冲击破坏的有效监测具有重要意义。红外热成像技术具有灵敏度高、非接触、无损监测等优点，在混凝土结构稳定性监测中得到广泛应用。然而，目前混凝土冲击破坏的红外辐射温度（IRT）演化规律和热效应机制尚不清楚。本研究利用落锤（DH）试验机、压力试验机和红外热像仪对混凝土冲击破坏和静载破坏进行了红外监测实验。分析了DH冲击破坏混凝土的红外热像和IRT变化规律。比较了DH冲击与静载破坏的红外热效应差异及机理。结果表明:混凝土DH冲击破坏冲击部位存在红外高温点,平均红外辐射温度(AIRT)和最高红外辐射温度(MIRT)均突然升高。 MIRT的增幅是AIRT的数十倍。与静载破坏相比，混凝土DH冲击破坏的红外高温区域集中，而静载破坏的IRT整体增大，且受热面积较大。而且，DH冲击失效下IRT的变化远大于静载失效下的IRT变化。 DH冲击破坏下混凝土的红外热效应主要由热弹性效应、摩擦热效应和拉伸破坏吸热效应组成。获得的混凝土冲击破坏红外数据应重点关注最高和最低IRT变化指标。最高的IRT对应于冲击失效点，最低的IRT对应于拉伸失效位置。研究结果为监测冲击破坏下混凝土的稳定性提供了一种新的红外热效应方法。