Deterioration of longitudinal joints is widely recognized as one of the major factors contributing to failure of asphalt pavements. Finding ways to improve the durability of longitudinal joints will lead to improved service lives and lower life cycle costs. Research and field trials have been directed towards improving joint performance since at least the 1960s. Most of that work was addressed improving the density at and around the joint. This report summarizes an extensive review of the pertinent literature, a review of state specifications and inspection of several trial projects in Indiana related to longitudinal joint construction and performance. Recommendations are given for new and continuing efforts to encourage or require the construction of durable longitudinal joints.

Construction of durable longitudinal joints is a critical element in the longevity of Hot Mix Asphalt (HMA) pavements. Achieving uniform density both longitudinally and transversely on the pavement will assist in meeting the goal of high-performance HMA pavements. A variety of techniques have been successfully used to construct good longitudinal joints. The objective of this document is to identify proper techniques for the various procedures, not to recommend a single technique.

The density and air void content of asphalt mixtures affect the durability and performance of asphalt pavements. Pavement longitudinal joints typically have a lower density than the mat because they receive less compaction than the center section of the mat for various reasons. The higher air void percentages resulting from lower densities can lead to high permeability and allow water infiltration, which in turn can cause moisture-induced damage and decrease base and subbase support to the pavement, reducing pavement life. Void-reducing asphalt membrane (VRAM) has been used at the longitudinal joints of asphalt pavements to achieve higher densities and prevent moisture infiltration, thereby reducing deterioration at the longitudinal joints. VRAM is applied before the hot-mix asphalt (HMA) layer is placed and migrates into the HMA to fill 50% to 70% of the air voids. This research evaluated the extent to which J-Band, a VRAM product, increases density and improves performance. Field cores were collected from two sections, one with and one without VRAM. Asphalt mixture performance tests, including disk compact tension and semi-circular bend tests, and push-pull tests were carried out in the laboratory on the field-collected specimens. Volumetric measurements were also taken, and ground penetrating radar was used in the field. It was determined that the pavement sections with VRAM had a lower permeability, higher bond energy, and higher fracture energy than the pavement sections without VRAM.

The objective of this research project was to conduct a literature review on longitudinal joint construction for hot- mix asphalt pavements. The review covered the issues related to the principles of hotmix asphalt paving and compaction for longitudinal joint construction, longitudinal joint problems, and some longitudinal joint construction techniques and specifications from different studies. Specific recommendations have also been made for application in the State of Kansas.

Construction procedures that will provide an improved centerline joint in asphalt concrete pavements.