PROBLEM TO BE SOLVED: To provide a crack-monitoring material and a crack-monitoring system, for economizing the inspection cost, enhancing inspection reliability, facilitating site work execution, and maintaining the detection function over a long period of time.
SOLUTION: When a crack C1 occurs beginning at an edge part of a lower flange 1b of a steel structure 1, a verge part of the crack-monitoring material 3 on the edge part side is partly broken, to cause a crack C1 to occur. The electrical resistance of a conductive layer 5a for crack occurrence detection is measured by an energized-state measurement part 9. Change in the electrical resistance is evaluated, by an evaluation part 11 to detect the occurrence of the crack C1. When the crack C1 further grows and progresses, the amount of decrease in the electrical resistance in a monitored area A1 is increased, in comparison with the amount of decrease of electric resistance in monitored areas A2 and A3. As a result, it is evaluated by the evaluation part 11 that the crack C1 has occurred in the monitored area A1, where the change in the electrical resistance is a maximum, to specify the occurrence position of the crack C1, while evaluating the scale of the crack C1 from the amount of change in electrical resistance.