Transportation Research Circular E-C248: 12th International Conference on Low-Volume Roads, TPF-5(379), September 2019

(2019) Transportation Research Circular E-C248: 12th International Conference on Low-Volume Roads, TPF-5(379), September 2019. Transportation, Department of

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Abstract

A majority of South Dakota roads are low-volume roads (LVRs). Simplified methods for LVR pavement thickness selection developed by the South Dakota Department of Transportation (DOT) allow users to obtain recommended asphalt surfacing and base course layer thickness based on the subgrade support and the average daily traffic (ADT). The main objective of this study is to relate the current surface condition of existing LVRs to their ADT, layer thicknesses, foundation material properties, and maintenance. A secondary objective was to determine if the surface condition of the roads is related to the level of compliance of the construction with LVR material and thickness selection methods. Sixteen asphalt surfaced LVRs were evaluated and tested. The construction and maintenance histories of the roads were obtained and the performance of the roads was evaluated based on the surface condition of the pavement. Field tests were performed to obtain the layer thicknesses, dynamic cone penetrometer index, and material samples for laboratory testing. Laboratory testing included moisture content, liquid and plastic limit, and gradation tests of the foundation soils. Test results were used to compare the layer thicknesses and material properties to the performance of the roads and the suggested thicknesses and material specifications from the South Dakota DOT guides. Based on the analysis, it was determined that layer thicknesses, material quality, and maintenance schedule have the greatest positive impact on a road’s performance when all of these components satisfy the guidelines in the South Dakota DOT Rural Road Design Guide.