Best Practices for Constructing and Specifying HMA Longitudinal Joints

Longitudinal joint deterioration continues to be one of the highest listed reasons for premature failure of hot-mix asphalt (HMA) pavements. Improving longitudinal joint construction is probably the single most important thing that can be done at this time to improve the performance of pavements. The purpose of this project was not to do additional research on longitudinal joint construction, but rather to evaluate the work that has already been done and to search for consensus to make recommendations on how to construct and specify longitudinal joints in HMA pavements. The approach taken was a series of stratified steps: 1) analysis of the Federal Highway Administration's survey to their state Division Offices on specifications, methods and performance of longitudinal joints; 2) review existing literature and research; 3) identify areas where there is consensus and areas where there is not; 4)conduct focused interviews with acknowledged paving experts and contractors whom recently won the prestigious annual Sheldon Hayes Award for the “best” HMA project in the United States; and 5) perform visits to states that have implemented a longitudinal joint specification (either minimum density or method specification) to meet with the department of transportation, contractors, and researchers and also to visit working projects. After accomplishing these steps and additional review of specifications and literature, recommendations were developed that offer the best chance of specifying and constructing longitudinal joints whose performance (life) will equal the performance of the mat. This guidance includes key steps or best practices for contractors, along with specification recommendations and options for agencies. A 4-hour workshop was also developed as part of this project.