Target Completion Date: October 31, 2026 Pavements
Ensuring the safety and functionality of Virginia's road and bridge infrastructure is a paramount responsibility of the Virginia Department of Transportation (VDOT). VDOT's specifications place significant emphasis on utilizing non-polishing aggregates in surface asphalt layers to ensure acceptable levels of friction (skid resistance) for the safety of the traveling public. Section 200.04 of VDOT’s Road and Bridge Specifications defines non-polishing aggregate as material capable of delivering acceptable skid resistance when exposed in roadway or bridge deck wearing surfaces. However, it is important to note that the department retains the authority to evaluate and decide whether proposed aggregates meet the standards for polishing characteristics. This indicates a potential gap in the existing guidelines or specifications regarding non-polishing requirements, as the specifications do not provide clear criteria in this regard.
A specific concern arises from the classification of carbonate aggregates, such as limestone and dolomite, as "polishing" based on their mineralogical composition. This categorization imposes restrictions on the use of these aggregates in most asphalt pavement surfaces, particularly in the western region of Virginia where carbonate rocks are the predominant source materials. Consequently, the transportation of non-polishing aggregates over considerable distances becomes necessary, leading to a substantial increase in construction costs and subsequent maintenance and rehabilitation expenditures, and associated environmental burdens.
The objective of this research study is to develop a criterion for evaluating the polishing characteristics of aggregates used in surface asphalt mixtures within a laboratory setting.
Last updated: June 6, 2024
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