Laboratory Evaluation of the Noise and Durability Properties of Asphalt Surface Mixes

This study made comparisons of the expected noise and durability performance of asphalt surface mixes based on laboratory testing only, and recommended a set of surface mixes for field test sections with improved surface performance properties. The study included a series of experiments to investigate the effects of several important mix variables identified in studies of field test sections, including nominal maximum aggregate size, aggregate gradation, binder type, additive, air-void content, and aggregate shape, on mix properties related to pavement surface performance. The study also included several other mix designs that had good or promising performance histories, and compared them with current Caltrans mixes in terms of laboratory test results. Specimens were prepared and tested in the laboratory. The performance indicators evaluated in the laboratory included durability, permeability, sound absorption, and friction. Durability included raveling, moisture damage, reflective cracking, and rutting. Friction included both macrotexture and microtexture levels. The study found that mixes with small aggregate sizes and either an asphalt rubber or polymer-modified binder, the Georgia 12.5-mm OGFC mix, and double-layer porous asphalts have good overall laboratory performance in terms of sound absorption, which is correlated with tire/pavement noise, and durability. However, performance evaluations in separate studies in the Netherlands indicated that the double-layer porous asphalt layers ravel faster than single-layer open-graded mixes. Therefore, this study recommends that the small aggregate size mixes with rubber and polymer binders, and the Georgia OGFC mix be further evaluated in field or HVS test sections.