Improving Asphalt Binder and Hot Mix Asphalt Aging Properties by Adding Synthetic Polyboron and Organic Magnesium Oxide

Abstract

In this study, asphalt binders were modified with polymeric triethylene glycol-based polyboron (PTEGB) and organic-based magnesium oxide (OBMO) at different concentrations. The materials used as additives were synthesized under our laboratory conditions. All modified and unmodified binders were aged by Thin Film Oven Test. (TFOT). The modified and unmodified asphalt binders firstly were evaluated by viscosity aging index obtained from a rotational viscometer. Then, all aged binders were subjected to Fourier transform infrared spectroscopy for obtaining the degree of oxidation. Also, the physical properties of the PTEGB and the OBMO-modified asphalt binders were detected through traditional tests. Marshall stability test was also applied to all aged and non-aged asphalt mixtures to understand mechanical performance and aging effects of the additives on asphalt mixtures. As a result, the optimum PTEGB percentage has been obtained as 2% (w/w), and the optimum OBMO percentage has been obtained as 1% (w/w) according to the aging indexes. The PTEGB and the OBMO additives decreased the TFOT aging of asphalts by 56.7% and 50.6%, respectively. It was also found out that the Marshall stability value of the hot mix asphalt decreased by 23% with the TFOT aging of the original asphalt binder. However, the same value was found as 7% at the OBMO-modified asphalt binder and 8.8% at the PTEGB-modified asphalt binder.