The study evaluated dense-graded mixtures and stone mastic asphalt (SMA) mixtures.
The dense graded evaluation included two variations of asphalt cement (85/100 and
120/150 penetration grade), three increments of shingle content (0.0%, 5.0%, and
7.5%) and three types of roofing shingles (fiberglass- backed factory scrap, felt-backed
factory scrap, and tear-off). The SMA mixtures were formulated with one grade of
asphalt, and one aggregate gradation. The mixtures incorporated either 10.0%
fiberglass-backed factory scrap shingles, or 10.0% felt-backed factory scrap shingles.
An SMA control mixture contained 0.3% cellulose fiber by weight of mix.