Effect of Waterproofing Membrane on Debonding of Asphalt Layer on Bridge Deck—A Simulation Study

In the recent past, the early, failure of asphalt pavement overlays on concrete bridge deck on newly constructed bridges in Goa has been noticed. The waterproofing membranes placed over the bridge deck have been predicted as a significant cause for this debonding. Potential reasons for the failure of asphalt overlay were thought to be due to poor adhesion between waterproofing membrane and asphalt wearing course, and complex behavior of asphalt layer. By studying the exact behavior of asphaltic layer overlaid on waterproofing membrane under action of dynamic loads and cyclic temperature variation, it is possible to understand causes of such failure. It is also possible to predict the initiation of debonding and its effect on pavement. In this paper a Multiphysics model of bridge deck overlaid with asphaltic layer on waterproofing membrane has been modeled. The behavior of asphaltic layer under the influence of cyclic temperature load has been analyzed. By determining the combined behavior of asphaltic layer and bridge deck, the initiation of debonding and its effect on pavementis studied. Further passive thermography pseudo experiments are conducted on a bridge deck overlaid with asphaltic layer to detect and identify damages in asphalt and base course. The damages were artificially created in the FEM model and passive thermography is simulated. It is found that thermographs obtained clearly shows the presence and extent of damages in the asphaltic layer. This study helps early detection of debonding and hence enabling repair and replacement strategies at appropriate location without losing much time in locating hidden damages below the road surface which in turn increase the service life of asphalt overlays on concrete bridge decks in Goa.