Achieving Asphalt Pavement Density with Minimal Mat Defects

It is well established that in-place density significantly influences asphalt pavement performance and service life. This paper discusses solutions to challenges that agencies and contractors often face when trying to achieve density requirements, or increase density, while eliminating compaction-related mat defects during the construction process. The basics of the asphalt pavement compaction processes, equipment, operations, and asphalt mixture densification are first presented, followed by information collected on a series of FHWA sponsored departments of transportation (DOTs) density demonstration projects. The authors then summarize the root causes associated with challenges in obtaining the desired density without compaction-related mat defects in a series of categories based on the DOT demonstration projects and experience assisting contractors with obtaining density on hundreds of projects. Examples are described for each category along with potential opportunities for improvements to overcome them. The demonstration projects illustrated that it is possible to make improvements when agencies and contractors embrace the idea of increasing density and reducing mat defects.