Modifying HMA stone aggregates prone to stripping with lime-based additives

Abstract

"Stripping" has been known as one of the foremost problems associated with Hot Mix Asphalt pavements since the beginning of asphalt pavement practices. This paper mainly relies on the concept of surface charges in the aggregate-asphalt-water interface. According to this rationale, extent of aggregates surface charges determines their degree of propensity to stripping. This research presents an experimental approach to understand the interaction of lime additives and mineral aggregates in different treatment settings. Three sources of aggregates with different mineral compositions and propensity to stripping were tested. X-Ray Fluorescence and Petrographical analysis were used to identify rock surface elements. Qualitative stripping tests were applied to evaluate the percent coating retained after stripping in different treatment scenarios. Zeta potential of powdered aggregates before and after different treatment settings were measured accordingly. This study identifies any significant correlation among percentage of siliceous minerals in aggregates, their zeta potential characteristics and stripping propensity