Intersection-approach pavements often experience extreme forms of distress long before the tangent segments of the same pavement and long before the design life of the pavement is attained. Field and laboratory investigations of asphalt concrete intersection-approach pavements were conducted to determine the primary causes of premature failure and in order to suggest changes in materials specifications, pavement design, and construction procedures that can be used to prolong the service life of intersection pavement. The primary mode of failure of the intersections studied was rutting; in some cases shoving and flushing also occurred. The leading materials-related cause of pavement failure was asphalt content in excess of the design value. Most of the mixtures studies contained relatively high percentages of natural (uncrushed) sand and low voids in the mineral aggregate. Modifications in materials specifications, laboratory test techniques, design procedures, and construction methods are suggested to provide a margin of safety to minimise early failures. The potential for significant economic benefits appears promising if intersection approaches are designed and constructed to accommodate the special stresses to which they are subjected.
Abstract