The Pennsylvania Department of Transportation (PennDOT) recently completed a 31,000-ton
asphalt rubber gap graded friction course project on I-78 (MP11-16) in Berks County, PA.
The project, identified as ECMS 87631, was developed, designed, specified, bid, awarded and
constructed in less than one year from the time PennDOT officials first observed field production
and placement of similar material on Route 146 in Massachusetts in November 2011. Bureau of
Maintenance and Operations (BOMO) Director Charles Goodhart, along with BOMO Materials
Innovation Management Section Chief Scott Nazar, attended a field visit to the MassDOT
project under construction while in Boston for the 2011 Northeast Pavement Preservation
Partnership meeting last fall. They were so impressed with the product and process that they
made it a goal to find a reasonable candidate to construct in 2012 as a research project.
Using MassDOT’s asphalt rubber gap graded friction course specification as a guide, they
developed their own specification to incorporate into the I-78 job. It was bid on June 28, 2012
and ultimately awarded to Reading Materials, a division of the H&K Group of Companies, from
Skippack, PA. Working with All States Materials Group, a mobile field blending operation was
set up at H&K’s Lebanon Materials plant located in Annville, PA. Mix designs were developed
by H&K’s corporate lab in Skippack and the test strips were placed on August 24, with final
paving completed on October 15, 2012. Processed tire rubber for the project was supplied by
Liberty Tire Recycling in Pittsburgh, PA. This also was a WMA specification with the contractor
electing to supply Evotherm 3G pre-blended in the PG 64-22 liquid from NuStar Asphalt to the
AR blending operation. The paving work was performed by H&K’s Windsor Services division.
The project scope included milling the 13-year-old bituminous pavement to the existing PCC
surface, spall repairs, FWD testing, full-depth concrete repairs where needed, placement of 1.5-
2 inches of AR GG leveling course followed by 1.5 inches of 12.5mm AR GGFC . Final
quantities were approximately 240,000 square yards of milling, 16,000 tons of variable depth
leveling, and 15,000 tons of 1.5-inch AR GGFC wearing surface.
I-78 is a very high-traffic interstate that connects the I-81 and I-83 commercial traffic corridors
through eastern Pennsylvania to Port Elizabeth, NJ. This was a night paving operation and
included a 1 mile control section with standard leveling and Superpave 9.5mm mix using PG 76-
22. This project also included PennDOT’s new longitudinal joint density specification, an
incentive/disincentive spec that measures joint density by field cores. Joint density results were
extremely impressive between 91-95 percent with the average in the 92-93 percent range. The
contractor achieved bonus for both joint density and smoothness incentives. The project
performance will be monitored by PennDOT’s New Products & Innovation Division along with
BOMO as a research project with hopes of developing this mix as a future preservation overlay
for high volume interstates in the commonwealth.