This paper presents the preliminary results of an ongoing study using Ground Penetrating Radar (GPR) for locating subsurface anomalies in concrete bridge decks and pavements with and without asphalt overlay. Specimens were cast in the laboratory with varying internal conditions such as with or without reinforcement and with air- or water-filled cracks. These specimens simulate the conditions of field bridge decks and pavements. The radar waveform obtained from these specimens were studied to determine the effect of subsurface cracks on the radar waveform and to assess the sensitivity of the technique.