Repeatability, reproducibility, and sensitivity assessments of thermal and fatigue cracking acceptance criteria for asphalt cement

A total of 54 asphalt cements were recovered for pass/fail testing according to various protocols. AASHTO M320 and proposed Glover-Rowe acceptance specifications appear permissive and lack precision. In contrast, Critical Crack Tip Opening Displacement (CTOD) and limiting phase angle temperature T(delta = 30 degrees) are able to identify satisfactory performing binders with a high degree of repeatability, reproducibility, and sensitivity. Deficits in performance ranged from minor to severe for materials in service for only 4-5 years. A practical specification based on ductile strain tolerance and T(delta = 30 degrees) is anticipated to provide a high degree of protection against premature and excessive thermal and fatigue cracking distress. (C) 2020 Elsevier Ltd. All rights reserved.