Midwest Transportation Center

About the research

Holding strategies is an approach that began being considered and assessed by the Iowa Department of Transportation (DOT) in 2013. Assessment of several holding strategies was initiated with the construction of ten different test sections over 13.6 miles on Iowa Highway 93 between Sumner and Fayette. IA 93 is a lightly traveled two-lane rural highway with a flexible pavement system. The annual average daily traffic (AADT) on this road was 1040 with 3 percent heavy vehicles. A pavement condition survey conducted in July 2013 prior to construction indicated that the existing pavement was in poor condition with a pavement condition index (PCI) of 32. According to the ASTM designation, standard practice for roads and parking lots pavement condition index surveys, roads with PCI values less than 55 are considered to be in poor condition and require maintenance improvement to increase the drivability of the road. The predominant distress type of the existing pavement was top-down cracking. Severe raveling, potholes, and edge breaks were also observed during the pavement condition survey. The objective of this study is to evaluate holding strategy treatments that can be used to improve the serviceability and extend the service life of a deteriorated low-volume road.