Whitetopping and Hot-Mix Asphalt Overlay Treatments for Flexible Pavement: Minnesota Case History

In 1993, two hot-mix asphalt and four whitetopping overlay test sections were constructed on low-volume road TH 30 in southern Minnesota. A study was undertaken to examine the performance and costs associated with the test sections after 9 years of service. The field testing and evaluation are described, and the costs incurred through 2001 are tabulated. The hot-mix asphalt overlay test sections are performing up to their design expectations. Routine preventive maintenance has been applied to both hot-mix asphalt test sections, adding to their long-term cost of operation and ownership. The whitetopping test sections are performing very well at the midpoint of their design lives of 20 years. Most distresses to date are related to poor construction and materials rather than inherent design features. Some random longitudinal cracking has occurred in areas of the whitetopping control section. The doweled test section has numerous distressed transverse joints caused by dowels near the surface of the slabs. There is virtually no faulting of the transverse joints, and the ride quality has stabilized. No maintenance has been performed on the whitetopping sections through 2001. As of 2002, the most economical overlay design in this study is a 6-in.-thick bonded whitetopping. On the basis of recent observations, it appears that whitetopping performs well and is an economical option for rehabilitation of low-volume roads in Minnesota.