Flexible pavement longitudinal joint quality evaluation using non-destructive testing

Longitudinal joint construction quality is critical to the life of flexible pavements. Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies. Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance. Current quality control (QC) and quality assurance (QA) plans provide limited coverage. Consequently, the risk of missing areas with poor joint compaction is significant. A density profiling system (DPS) is a non-destructive alternative to conventional destructive evaluation methods. It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics. The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality. The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint. The paper proposes a dielectric-based longitudinal joint quality index (LJQI) to evaluate the relative compaction of the joint during construction. It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints, identify locations of poor quality during construction, and achieve better-performing flexible pavements.