Evaluation of long-term performance and identification of nonhomogeneity, incompatibility, and hardening rate of hot-mix-recycled bituminous pavement are described. The effects of artificial laboratory aging on a virgin binder (ac-20) and three other--extracted and recovered--rejuvenated binders were determined. Laboratory aging was achieved by means of the thin-film oven test (tfot). Analysis and evaluation of the test data revealed some important aspects of hot-mix recycling. The tfot was identified as a potential added criterion inidentifying recycling agents that tend to cause a high rate of hardening, nonhomogeneity, and noncompatibility problems in recycled binders meeting the standard specifications of a virgin binder. This identification can be obtained by visually inspecting the residues after the tfot and classifying their consistency using penetration and viscosity tests. This paper appears in transportation research record no. 1269, Asphalt mix materials and mixtures 1990.
Samenvatting