Cracking potential of short- and long-term aged binder with various levels of ABR

It is widely accepted that using reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) could improve the sustainability of asphalt concrete (AC), in terms of cost savings and environmental factors. This should be only valid when short- and long-term pavement performance are not compromised. This thesis presents an experimental evaluation of the rheological properties of binders from various sources to investigate the effects of aging and increasing asphalt binder replacement (ABR) levels. In addition to the standard Superpave grading parameters, the additional rheological parameters for low-temperature cracking susceptibility and block and fatigue cracking were derived from various dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. Binders from five AC designed with varying ABR percentages (from 0 to 60%) were recovered using the standard Rotovap test procedure. The base binder used in the AC design and binders recovered from RAP and RAS were also tested. In addition to standard aging protocols, base binders were subjected to a second pressure aging vessel (PAV), while one PAV was applied for the extracted binders. Almost all additional rheological parameters appeared to maintain consistent trends with aging and increasing ABR levels. The considered parameters are shown to be helpful in evaluating progression in the brittleness of binders with ABR and aging. Based on the outcome of the experimental program (binder level and mixture level), it was concluded that AC with ABR levels above 20 percent could suffer from short- and long-term cracking potential. Asphalt concrete with high ABR content can already be at a critically-aged condition immediately after production and, as a result, aging progresses much faster in the binders of such mixes