Evaluation of significant factors for aggregate retention in chip seals based on mesostructured finite element model

Abstract

The retention of aggregates or chips on chip seal is critical for the durability of chip seal application in pavement maintenance. Most evaluation on aggregate retention have focused on laboratory experiment regarding asphalt-aggregate bonding, however, there are many other factors that are needed to be investigated as a whole picture. As such, this paper presents a mechanistic point view of understanding the effects on the aggregate retention based on a two-dimensional finite element model of aggregate-asphalt interface. The horizontal strain and shear strain in the interface are evaluated in terms of six factors including asphalt type, temperature, loading level, horizontal loading, aggregate shape, and interface bonding conditions. The analysis of variance (ANOVA) of influencing factors for critical response is further conducted. The results show that shear strain is more significant than the horizontal strain, which should be taken as an evaluation index for aggregate retention in chip seal. The influence of six factors on the shear strain of aggregate-asphalt interface is highly significant. The greatest significant influence is temperature, followed by horizontal loading, asphalt type, loads, aggregate shape, and interface bonding conditions. The results of this study provides a mechanistic viewpoint for chip seal designer to consider varying conditions for ensuring aggregate retention in chip seal.