Laboratory Evaluation of the Effect of Nano Al2O3 on High and Intermediate Temperature Performance of Asphalt Binder and Hot Mix Asphalt Mixture

Composite modification is increasingly used to alleviate the detrimental problems associated with asphalt modifiers and meet the massive demand for asphalt pavement. In this study, nano-Al2O3 composite modifications at three concentrations of 1%, 2%, and 3% by weight of asphalt binder were implemented in neat and modified asphalt binders to improve their performance at high and intermediate temperatures. These binders were evaluated in terms of their physical, rheological, and high-temperature storage stability properties. In addition, nano-Al2O3 composite modified binders were utilized in asphalt concrete and investigated for their resistance to cracking, permanent deformation, and moisture damage. The nano-Al2O3 composite modifications were made using neat, polymer-modified, and crumb-rubber (CR) modified asphalt binders. Adding nano-Al2O3 to the asphalt binders was found to improve stiffness, high-temperature storage stability, permanent deformation resistance, and cracking tolerance. Moreover, the composites of nano-Al2O3 with neat and modified asphalt binders were found to provide improved resistance to permanent deformation, cracking, and moisture damage in hot mix asphalt concrete. The composite of 2% nano-Al2O3 showed the best performance in terms of resistance to permanent deformation, the composite of 3% nano-Al2O3 showed the best performance in terms of resistance to moisture damage, the composites of 2% nano-Al2O3 with polymer and CR-modified asphalt binders both showed the best performance in terms of resistance to cracking, and the composite of 3% nano-Al2O3 with AC20 showed improved resistance to cracking.