Characterization of Pavement Distress from Test Pit Observation

The characteristics of the roadbed material are critical to the overall performance of the pavement. The paper presents examples with discussion of the form of distress experienced within the pavement layers, based on observations made during the profiling exercise of an investigation into the causes of the premature failure of a pavement. The field investigation entailed a detailed inspection and recording of the profile exposed in test pits, with particular attention being paid to areas with cracks, noting their positions and extent within the pavement layers. The focus of the paper is on the observed orientation of crack propagation within the pavement layers. It is shown that the crack propagation is not always in the vertical plane. This has implications in dealing with crack sealing procedures. The causes of the observed distress were attributed to the behavior of the roadbed as it experienced fluctuating moisture conditions.