Field Trial of Infrared Joint Heater to Improve Longitudinal Joint Performance in New Hampshire

Longitudinal joint cracking is one of the most prevalent forms of distress in asphalt concrete pavements. The joint area does not achieve the same density as the mat because of an unconfined edge on the initial pass and a cold joint during the second pass. The lower density allows water to penetrate, and the material cracks, usually within a year of construction. There are many techniques for constructing longitudinal joints; one is to preheat the joint before paving the second lane. A field study conducted in New Hampshire used an infrared joint heater on the base, binder, and surface layers of a full-depth hot-mix asphalt pavement. Thermocouples were embedded in the pavement to determine the extent of heat penetration from the infrared heaters. Cores were taken along the joint and in the travel lanes for both control and infrared test sections. Density and strength measurements taken on the cores show some statistically significant improvements in the joint constructed by using the infrared heater. Permeability measurements along the control and test joints were performed and show average differences between the two sections. Cracking surveys on the binder and surface layers performed 1 year after construction showed that the section of pavement where the infrared heater was used has significantly less cracking than the control section.