Asphalt Materials’ J-Band® Void Reducing Asphalt Membrane

To achieve density and prevent intrusion of water at the longitudinal construction joint, contractors have to adhere to best practices. They can get some help from the start of construction with the J-Band® void reducing asphalt membrane (VRAM)—or longitudinal joint membrane (LJM)—from Asphalt Materials Inc., with headquarters in Indianapolis, Indiana. Here’s how it works.

Before paving, the contractor uses a distributor truck with a parallel spray bar and four adjustable nozzles to spray J-Band as a heavy fluid asphalt membrane under the intended longitudinal joint. The spray nozzles are installed at various angles to effect a triangle/fan pattern and control the width and thickness of the spray, resulting in a 12 to 18-inch-wide strip of 5/32 of an inch thick emulsion. Note, the thickness may be slightly more or less depending on the thickness of the hot-mix asphalt lift to be placed.

Based on ambient temperature, the hot-applied material cures in approximately 15 to 30 minutes to a non-tracking stripe.

The paving crew makes the first pass with HMA material, covering one-half of the J-Band to create—or begin building—the joint. The roller then helps J-Band migrate into HMA voids, at a rate of 50 to 75 percent, at the cold joint during normal rolling patterns. The migration of J-Band into the HMA voids results in reduced joint permeability and minimal joint cracking.

For more information, contact Bob Khanna at (330) 441-0478 or bob.khanna@asphalt-materials.com.