Damage Quantification Using an Improved b-Value for Concrete Slabs

Quantitative evaluation of concrete bridge decks is in high demand to establish a rational maintenance program. Visual inspections, sounding with tapping, or core samples have so far been used to determine the level of damage in the maintenance program. As these conventional methods have certain drawbacks (e.g., invisibility of bottom plate-reinforced slabs and difficulty of access on high elevated bridges), the results depend greatly on the operators’ skills, a destructive approach, and some points’ information can not reflect the whole of the deck, in turn. Accordingly, the authors have studied other techniques that evaluate the overall members’ damage by means of elastic techniques with use of acoustic emission (AE) and several tomographic approaches. In AE tomography, for example, concrete properties can be represented by elastic wave velocities; thus, partial damage can be visualized as a small-velocity area. With use of this technique, detailed investigations could be reasonably implemented; however, overall evaluation exhibiting the integrity of a unit of a bridge panel, which is required to establish repair and maintenance programs, would not be obtained. Therefore, in this study, an overall representative index for bridge panels is studied with use of an improved b-value.