Modifying HMA stone aggregates prone to stripping with lime-based additives under controlled curing conditions

"Stripping" has been known as one of the foremost problems associated with Hot Mix Asphalt pavements since the beginning of asphalt pavement practices. "Stripping" is a physiochemical phenomenon and defined as moisture damage to HMA due to separation of asphalt cement molecules from the surface of stone aggregates. Among different theories explaining the stripping mechanism, this study mainly relies on the concept of surface free charges in the aggregate-asphalt-water interface. According to this rationale, extent of aggregates surface charges determines their degree of propensity to stripping. Application of lime-based additives is a conventional treatment for improving the problematic aggregates. This study discusses an experimental approach to identify any significant correlation among percentage of siliceous minerals in aggregates, their zeta potential characteristics and stripping propensity. Also a procedure will be presented for studying the effect of temperature and pressure on the healing behaviour of lime in reaction with rock aggregates.