Any paving foreman will tell you there is no room for error when you’re placing a lift that’s only three-quarters of an inch thick. One mistake and it’s almost impossible for the roller operator to correct it.
The thin mat cools quickly, giving the rolling team little time to press out the voids. Speed may feel like the name of the game, but let’s begin slowly. Let’s do some planning to get the ultra-thin lift pavement treatment performed right.
An agency might request an ultra-thin lift for a pavement that has a pavement condition index (PCI) of 70 or greater. When the agency assigns this treatment, the contractor is working to protect a surface from oxidation, to maintain grade and slope, and/or to address minor distresses, among other things. There’s not a lot of room to play with.
Begin with cleaning. If the surface you plan to overlay is coated with dirt, dust, leaves, rocky material or other detritus, tack or asphalt mix will stick to the undesirable particles. When those particles are swept away by brooms, snow plows, vehicle tires or whathaveyou, the desirable material—your pricy product—goes with them. This is nothing new to paving contractors. Be sure the cleaning of the surface is included in your bid and your work.
The next step is tacking for a good bond. Continue reading…