Análise dos parâmetros reológicos através das curvas mestras do ligante asfáltico modificado por SBS e EVA

Abstract

The Brazilian asphalt binder from Fazenda Alegre oil reserve in the state of Espírito Santo, was modified by polymers (SBS and EVA) and additives (oil extensor and hydrated lime). The resulting rheological effects of this modification were evaluated, using rheological assays based on the Superpave specifications. The oxidative ageing of the asphalt was evaluated from the variations of the rheological parameters. The most significant effect of the polymer incorporation to the asphalt was the improvement of the elasticity. For the modified asphalt binder, a significant increase was noted in the G* in lower frequencies, where a network of the polymers SBS and EVA are particularly dominant, and a small decrease on the G* in higher frequencies. It was also observed a decrease in the tang δ and this indicates that the formation of a polymeric network, which gives the binder an elastic stability at higher temperatures, has occurred. Among the asphaltic mixtures produced, it was observed that the binder modified by the EVA and the hydrated lime, demonstrated a higher rigidness and elasticity before and after the ageing. The susceptibility relative to the temperature of the asphalt mixtures measured through the flow activation energy, demonstrated that the mixture containing EVA degrade less than that contain SBS.