Recently, many cases of initial flaws, damage and deterioration of road bridge slabs have been reported. Securing the heat source and detection and evaluation of changed sections by the thermography method are problems, however, because slab bottoms are shaded and temperature differences from changed sections cannot be anticipated. We studied the relationship of internal flaws and surface temperatures using the pavement heat of asphalt improvement work. As a result, surface temperature distribution corresponding to flaw slopes was confirmed in the heat image from pavement heat transfer, making it possible to detect internal flaws and flaws in contact with surfaces. The effectiveness of using pavement heat is clarified through comparison with the passive method and the three dimensional unsteady heat simulation.
