Investigation of the Effect of Iron and Aluminum Nano-oxides on Reduction of Moisture Sensitivity in Hot-mix Asphalt

There are several different approaches for reducing moisture sensitivity in asphalt mixtures, which one of the most one of them is using anti-stripping additives. These anti-stripping additives are added to asphalt binder, aggregates or their mixture. In this study, two types of nano-materials (Fe2O3 and Al2O3) are introduced as anti-stripping additives and asphalt-binder modifiers. Two types of aggregates with different moisture sensitivity potential (limestone and granite), AC 60-70 from Isfahan Refinery and two types of nano-materials (Fe2O3 and Al2O3) as two weights of asphalt binder (2 and 4 percent) were used in this research. The effects of using nano-materials as anti-strip additives on moisture sensitivity of hot-mix asphalt have been assessed by the modified Lottman test (AASHTO T283 test). The results of AASHTO T283 test showed that use of nano-materials increased tensile strength ratio in samples containing modified asphalt-binders. Application of nano Fe2O3 had an obvious effect in decreasing moisture damage potential of asphalt mixtures, as compared to nano Al2O3. Another result that was obtained in this study was that similar to the previous studies, samples made from limestone aggregates performed comparatively better against moisture damage.