ENHANCING POROUS FRICTION COURSE DESIGN: INCORPORATING WARM MIX ASPHALT AND PERFORMANCE-BASED DESIGN

Abstract: Porous Friction Course (PFC) mixtures are widely recognized for their ability to enhance pavement safety, drainage, and noise reduction. However, the high air void content that characterizes these mixes poses significant durability challenges. This study addresses these issues by comparing the performance and permeability of PFC mixes utilizing various stabilizing agents and Warm Mix Asphalt (WMA) technologies. Through a comprehensive series of performance-related tests, the research investigates the intricate relationship between mix composition and performance and durability of PFC mixes.
The study evaluates critical properties such as raveling, binder drain-down, moisture susceptibility, permeability, rutting, and cracking through several performance and durability tests. Special attention is given to surface texture and friction tests, as these factors directly impact road safety. The significance of these tests, their correlation with field performance, and their repeatability, ease of performance, and reliability are assessed based on previous literature.
PFC mixes are designed and prepared in accordance with Oklahoma Department of Transportation (ODOT) specifications, incorporating various stabilizing agents like fibers and polymers, along with WMA technologies. The mixes undergo characterization using tests such as the Cantabro abrasion test, Hamburg Wheel Tracking test, Indirect Tensile Asphalt Cracking Tests and permeability tests. Additionally, PFC slabs are prepared for friction testing to evaluate the impact of mix composition on surface friction.
A key objective of this research is to incorporate performance testing into the design process of PFC mixes. The test results are analyzed to optimize PFC mix designs based on performance data, leading to recommendations for the selection and use of stabilizing agents and WMA technology. Furthermore, the study aims to develop and refine performance criteria for PFC mixes and propose a specification for PFC using performance-related testing. These changes allow for the relaxation of existing volumetric criteria required by ODOT while incorporating performance-related testing during mix design.
The results of this research highlight the significance of incorporating performance testing as part of the mix design of PFC mixes. Based on the results of this study, recommendations are made to revise the PFC specifications to incorporate performance testing to ensure satisfactory performance and skid resistance.