Minnesota Department of Transportation
Chris Williamsrwilliam@iastate.edu email >
About the research
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.