The objective of this paper is to document case studies of pavements that have rutted prematurely. The investigation of the nature and cause of the rutting includes study data from cores, beams across the lane widths, mix designs, nondestructive testing, and traffic data. Three projects are presented in this documentation, two of which rutted prematurely and one of which is identified as rutting-resistant. The rutting in the first project was caused by overcompaction in construction, which was the result of mix design, quality control, and inadequate construction standards. Premature and long-term rutting were both shown in the second project. The rutting was found in all layers of the asphalt, and rutting continued after each corrective action. This problem resulted from a combination of mix and structural designs. The third project used a 4-in.-Thick stone-filled binder and surface over a 6-in.-Thick, regular dense-graded asphalt base. The stone-filled mixtures are generally higher in initial air-void content and can be compacted to a higher percent of laboratory density in construction. They do not seem to be sensitive to asphalt content and are in that respect not subject to additional compaction under traffic. The void-in-mineral-aggregate curve is usually very flat and shows little change with the asphalt content.
Abstract