Investigating effect of amine based additives on asphalt rubber rheological properties

Abstract

This paper investigates merits of introducing bio-binder and liquid Warm Mix Asphalt (WMA) additives to asphalt rubber to enhance its rheological properties. It is hypothesized that amine-based liquid additives can facilitate rubber devulcanization and speed up the release of rubber polymer into the asphalt matrix. This in turn can enhance asphalt rubber rheological properties including high temperature properties. This paper specifically focuses on high temperature properties and temperature susceptibility of the asphalt rubber modified by amine-based additives. High temperature properties were investigated by quantifying the effect of warm mix asphalt additives (Rediset and Evotherm) and bio-binder on the shear susceptibility and temperature susceptibility of asphalt rubber. Ambient crumb rubber with 10% and 15% concentrations by the weight of asphalt binder was used in this study. The rotational viscometer was used to evaluate the effect of additives on the asphalt rubber high temperature properties and pumpability. FT-IR analysis was studied to determine presence of devulcanized rubber polymer inside the asphalt matrix. It was found that all three additives reduced the viscosity and improved the pumpability significantly. In addition, the effect of additives found to be more significant when higher percentages of rubber were used. Additives with higher perecentages of amine compunds found to be more effective in devulcanizing rubber.