In the mid-80's I was travelling I83 around Harrisburg daily. At one point a road crew was resurfacing it between the Eisenhower Interchange and the river with some sort of modified blacktop. We drove on it literally minutes after it was laid. Following the crew we were in both lanes, then moved into a single lane to pass by the work crew as they progressed. One of the local TV stations did a short story on the material, but I don't recall what it was. I think they also used it on some off-ramps where they had trouble with the surface developing buckles from heavy vehicles. It looked like regular blacktop, and as far as I know, it held up well.