Rode past the site this morning. Looks like the fill is within a few feet of final grade. My guess is the road reopens later this week with six lanes available. My over/under is Wednesday (6/21). If so, that would be 11 days.
The fill material is a manufactured product called Ultra-Lightweight Foamed Glass Aggregate (UL-FGA). It is made from foamed, recycled glass and is 85% lighter than traditional gravel fill. This allows 100 cubic yards to be hauled by one truck. It is more-or-less self-compacting, so you can just place it and smooth it. If it settles a bit, the roadway can be leveled off later with a blacktop overlay.
UL-FGA (this may or may not be the specific gradation of the material being used here.)
PennDOT has a live stream of the work in progress at
PennDOT I-95. Buckley, the contract has made the most of the live stream and free publicity by placing at least four large signs facing the camera.