Aggregate Base CourseCourse-ground shingles (2½”
minus) can be added to aggregate materials as part of the lower
pavement layers—the sub-base, base, or binder courses.
Hot Mix Asphalt (HMA)Fine ground shingles (½” minus)
can be added at 5% by weight of HMA for use in the wear/
surface course. Shingles are added to HMA in the same manner
as recycled asphalt pavement (RAP). The shingles can replace
some virgin asphalt and aggregate. This substitution, however,
usually requires the use of a softer virgin asphalt to offset the
effect of adding the harder asphalt in the recycled shingles.