The shingles contain valuable bitumen and a cubical aggregate
product that works well in a variety of end products, especially in the paving industry," says William Turley, executive director of the CMRA.
Within-aggregate roots were saved for counting and measurement, identifying slice number (position within the column), in addition to replication, cubical aggregate size and soil density.
Soil columns, 25 cm high and 20 cm in diameter, were artificially assembled with cubical aggregates of three different densities (1.
Roots were collected from the surfaces between slices and between aggregates by slicing off (at the surface) those that penetrated the cubical aggregates.