Exploring aggregate influence on long-term skid resistance in South Africa

Abstract

Skid resistance is an integral part of the road conditions that influence road safety on paved roads. Amongst other factors, the aggregate type used to construct wearing courses significantly affects the skid resistance of flexible road surfacing. Understanding the influence of aggregate mineralogy on skid resistance provides an opportunity to enhance road safety and optimise material selection for wearing course construction. This paper presents the correlation between the characteristics of aggregates used to construct wearing courses in South Africa and their long-term skid resistance performance. In this study, some of the commonly used aggregate types in the construction of wearing courses in South Africa were assessed for their mineralogical properties and long-term skid resistance performance after simulated traffic polishing. This study established that the aggregate types with a higher hardness, which is a property primarily dependent on the mineralogical makeup of an aggregate, tended to retain their surface texture better than softer aggregates. The study's results also noted that further research must be invested in determining the worst accuracy level required to achieve credible aggregate microtexture data.