The composition and properties of asphalt shingles are characterized in studies by the states of
Minnesota [1] and North Carolina [2], the University of Maryland [3], the National Asphalt
Pavement Association [4], asphalt plant manufacturer Astec Industries Inc. [5], and others.
There is good correlation in the information presented by the different entities, with only some
minor deviation in the details. Based on the studies it can be concluded: