Micro-scale study about interfacial interaction of emulsion-aggregate system for cold mix asphalt

The performance difference between cold mix asphalt and hot mix asphalt, generally it is associated with the interaction of emulsion-aggregate system during the mixing stage. Currently, performance indexes for the asphalt emulsion-aggregate system in terms of surface charge and surface energy to understand the compatibility between the components are unknown. In this study, the interaction of asphalt emulsion-aggregate systems was evaluated in micro scale using the Zeta potential and surface free energy (SFE) techniques for three asphalt emulsions and three sedimentary aggregates. The results showed that the three aggregates presented negative Zeta potentials. Additionally, it was observed reductions of the aggregates Zeta potentials respect to the asphalt emulsions pH value. Residual asphalts and aggregates presented low and high SFE values, respectively. Finally, compatibility of the emulsion-aggregate system was supported by high values of Zeta potential and SFE.