Use of aggregate nanocoating to decrease moisture damage of hot mix asphalt

In this research, the effect of using nanocoating on the surface of aggregates on moisture damage of the hot mix asphalt has been studied with thermodynamic and mechanical methods. Aggregates used in this research are granite and limestone which have been modified with nano calcium carbonate (CaCO3) and nano zinc oxide (ZnO). The obtained results in this research show that tensile strength ratio of samples made with modified aggregate has improved in comparison to the control samples. Results of surface free energy indicate that coating of aggregates with nanoparticles reduces the difference between the free energy of adhesion in wet and dry conditions which reduces the stripping tendency of asphalt mixtures. Also, coating of the aggregates with nanoparticles caused better wettability of the aggregates' surface by asphalt binder. The aggregates treated with nano CaCO3 showed better resistance against moisture damage in both the methods that were used in this study.