Investigating the Use of Nano Coating Over the Aggregate Surface on Moisture Damage of Asphalt Mixtures

One of the methods to improve adhesion between asphalt binder and aggregate and to reduce moisture susceptibility in asphalt mixtures is aggregate treatment using suitable coats which cause to change aggregate polarity. In this study, effect of nanomaterial coating on aggregate over moisture damage of HMA by means of thermodynamic and mechanical methods has been probed. Aggregates used in this study are granite and limestone that have been modified using iron oxide and aluminum oxide nanoparticles. Results illustrate that in comparing modified samples through nanoparticles with control samples, tensile strength ratio on moisture condition surpasses dry condition. Surface free energy result shows that aggregate coat with nanoparticles leads to decrease in differences between free energy of adhesion in moisture condition and dry condition, and thus, stripping event is diminished. Nanopartides' positive performance of iron oxide compared with aluminum oxide nanoparticles in decreasing the moisture sensitivity of asphalt mixtures built is more evident about either kind of aggregates.