Infrared image detection method and mechanism of concrete micro-crack

Based on conductive film pull-sensitive effect, infrared image detection method of concrete micro-crack was put forward to solve the problem of long distance nondestructive detection. Firstly, basic principle of infrared detection technology was analyzed. Effect of environment temperature and atmospheric transmission process on target real temperature was considered. Secondly, conductive film electrothermal effect was analyzed. After electrifying, temperature of crack was higher than that of uncrack. Non-uniformity distribution of surface temperature was formed. Heat transfer mechanism of conductive film was discussed. Finally, infrared thermal image of conductive film was obtained by infrared thermal imager. Crack development process could be drawn under the action of external force. Combined with crack magnifier measurement, effect of conductive film emissivity on crack temperature was predicted. The relationship of crack width and temperature difference was discussed. The result indicated that the proposed detection method was feasible.