The goal of this study was to correlate the results of a laboratory test procedure measuring aggregate polish resistance with skid resistance in bituminous pavements. This correlation would be instrumental in identifying skid-resistant aggregates and would create the potential for assuring lifelong-skid-resistant bituminous pavements.
This study was conducted in two phases. The first estimated the empirical relationship between aggregate microtexture and cumulative polishing using a modification of the ASTM standards: Recommended Practice for Accelerated Polishing of Aggregates Using the British Wheel (D 3319-83) and Standard Method for Measuring Surface Frictional Properties Using the British Pendulum Tester (E 303-83). An exponential model was developed which realistically approximates the minimum polish value observed with the theoretical asymptote of the polishing rate curve. The magnitude of this asymptote, PV, correlated well with New Jersey's skid-resistance experience with specific aggregate types and was subsequently used in the study's second phase.
In the second phase of this study, a more detailed relationship between PV and long-term minimum skid resistance was sought. Experiments were conducted to evaluate polish values of aggregates and skid resistance of bituminous pavements composed of these aggregates and to collect environmental data on selected skid test sites over a period of one year. This information was used to normalize the skid resistance of a bituminous pavement in terms of the aggregate's polish value and cyclical environmental factors.
Because further refinement is needed, a tentative acceptance limit for aggregate prequalification may be identified using this relationship. Possible values for this acceptance limit may range from PV = 25 to PV = 32, depending upon the factors one chooses to include in this consideration.
Additional research is required to check and refine the models developed. This paper concludes with a detailed description of the work to be accomplished in order to finalize this analysis and implement a statistical specification for the prequalification of surface course aggregates based on polish resistance.