Evaluation of the Effect of Density on Asphalt Pavement Durability through Performance Testing

摘要

Considering the budget allotted to construct and maintain roadway surfaces, a 5 to 10 percent increase in their performance could potentially yield an annual savings of billions of dollars. Considering this, the Kentucky Transportation Cabinet (KYTC) launched a project to better understand the effect of in-place density on the durability of their hot-mix asphalt (HMA) pavements, which is known to be a crucial factor in HMA performance. Asphalt Institute in cooperation with KYTC embarked upon the research and collected numerous HMA samples from five pavement construction sites in Kentucky. A laboratory experimental plan was developed to examine the potential improvement in the mixtures’ performance if they were compacted to a higher and desired density. The laboratory test plan was comprised of flow number, flexural beam fatigue, and disk-shaped compact tension tests to evaluate the mixtures’ performance with respect to rutting, fatigue cracking, and low-temperature cracking. A statistical analysis of the results was performed to evaluate the effect of density on durability of each one of the pavements. The results showed that the service life of the pavements could improve considerably by achieving the target density of 92 percent. The compactibility of the HMA mixtures was also investigated through their compaction characteristic curves using the Superpave gyratory compactor. Based upon the compactibility analysis, the mixtures could be better compacted in the field by increasing their lift thickness.