Pavement Deterioration: Case Study

A case history of pavement deterioration is described. There were three pavement concerns: an inadequate pavement section, seepage of water through the base material, and settlement of utility backfill. The main pavement deficiency was the aggregate base, which in some locations was much less than the original pavement recommendations. Water migrated into the base causing the compacted clay subgrade to become wet with a corresponding reduction in shear strength. Because of the thin aggregate base, the pavement section could not sustain the traffic loads, resulting in alligator cracks, rutting and, in some cases, complete disintegration of the pavement. It was also observed that water was flowing through the aggregate base. For inclined pavements with a permeable aggregate base constructed on top of a clay subgrade, theoretical analysis indicates that the majority of water will flow through the base material instead of into the subgrade.