Development of a friction prediction model of asphalt concrete at the construction stage based on Sri Lankan aggregates

Abstract

The skid resistance at the tire-pavement interface ensures adequate braking force for road user safety. Insufficient friction at the wearing course emerges as the primary pavement-related factor of highway crashes. Governing factors of pavement friction include pavement properties, vehicle/tire/driver conditions, and environmental conditions, with pavement characteristics, particularly the mineralogical and textural attributes of surfacing coarse aggregates exerting dominant control. Coarse aggregate polishing resistance critically determines the available skid resistance of an asphalt concrete road, prompting extensive research on aggregate’s friction retention capacity under traffic loading. Hence, globally a number of pivotal studies have been conducted to explore polishing behaviour of roadstones and to develop prediction models to forecast skid resistance capacity of flexible pavements. In Sri Lanka, road safety garners increased emphasis amid expressway network integration, yet studies on local aggregate friction properties remain limited, with fewer user-safety guidelines incorporated in the national Standard Specifications for Construction and Maintenance of Roads and Bridges (SSCM-RB). This study thus evaluates friction characteristics of indigenous Sri Lankan road surfacing aggregates via the Polished Stone Value (PSV) test (employing Accelerated Polishing and British Pendulum) alongside petrographic and microscopic analysis of polishing behavior in order to develop a friction prediction model for national asphalt concrete pavements.