Performance of Micro- and Nano-Modified Asphalt Mixtures Through Flow Number and Moisture Susceptibility Evaluations

摘要

The objective of this study was to utilize micro- and nano-materials to improve the overall performance of asphalt mixtures through flow number and moisture susceptibility evaluations. The materials included non-modified nanoclay and polymer modified nanoclay, carbon microfiber, nanomer material, and nanosilica. These materials were mixed with the control asphalt to prepare the modified asphalt, and then, the modified asphalt was mixed with the aggregates to compact the modified asphalt mixtures. The Superpave performance tests were employed to evaluate the resistance to permanent deformation and moisture susceptibility of asphalt mixtures, including the flow number and indirect tensile strength tests. The microstructures of modified asphalt were examined by the field emission scanning electron microscope (FE-SEM) and the images helped to understand the modification mechanism. Statistical analysis was used to analyze the levels of impact of these modifiers on the improvement in performance. Based on the results of test data processing, (1) the flow number values of modified asphalt mixtures improved significantly, and it indicated that the rutting performance of modified mixtures was enhanced after the addition of these modifiers; the statistical analysis data revealed that all modifiers had a significant influence on the improvement in performance; (2) the dry and wet tensile strengths increased in most of the modified mixtures, and the statistical analysis results implied that most of the modifiers can greatly impact the moisture susceptibility of asphalt mixtures.