Diagnosis of moisture damage in asphalt pavements

Abstract

One of the most common modes of premature failure of asphalt pavements is water damage. Moisture damage in hot-mix asphalt (HMA) pavements occurs when water infiltrates the pavement system, causing premature failure of hot-mix asphalt pavements, primarily through loss of adhesion between the asphalt binder and the aggregates. Loss of adhesion can lead to stripping of the asphalt film from the aggregate and raveling, where aggregates are dislodged from the pavement. The laboratory testing procedures currently available for testing HMA moisture susceptibility were primarily developed to determine the degree of resistance to moisture damage by a particular combination of asphalt and aggregate as well as compare mixes composed of different types and quantities of aggregate. These methods are all based on destructive testing. There is currently a need for innovative nondestructive testing technologies that can be used to identify and isolate the effects of water damage in mixtures. As a first step in the development of a non-destructive method to test HMA pavements, modal hammer tests were conducted on several test specimens of fine and coarse grained granite-based mixes commonly used by the Florida Department of Transportation (FDOT). The results of the testing indicate that there is a large frequency shift in the transfer function measurements for the damaged samples compared to the undamaged samples. The results imply that modal hammer testing may be used as a method to characterize the health of HMA pavements.