Rheological Evaluation of Foamed WMA Modified with Nano Hydrated Lime

Abstract

Although the Warm Mix Asphalt (WMA) is gaining popularity very rapidly and becoming a mainstream technique for producing asphalt mixtures, there are many concerns regarding its long-term performance. Over the years, the Regular Hydrated Lime (RHL) has gained considerable recognition as a common additive to bituminous pavements. However, the Nano Hydrated Lime (NHL) (particle sizes 100 nanometer (nm) or less) has not been used as an additive to the asphalt mixtures before. The rheology properties of foamed WMA were studied since the pavement performance is primarily controlled by the rheological properties of asphalt cement. NHL materials with particle sizes of 50nm and 100nm were used in this study along with RHL to investigate the effectiveness of the new generation fabricated NHL modification on the rheological properties of the foamed WMA. NHL was added to the asphalt binder at ratios of 20%, 10%, and 5% (by weight). The foamed WMA was produced by adding Advera® at ratios of 3%, 4.5%, and 6% (by weight). The Dynamic Shear Rheometer (DSR) test was used to evaluate the rutting and fatigue cracking of the binders while the Bending Beam Rheometer (BBR) test was used to evaluate thermal cracking of the binders. The overall results reveal that the binder rheological properties can be enhanced successfully by adding small amounts of NHL. The NHL particle size affects the rheological properties of the binders. The application of the RHL with the normal dose (20% by weight of binder) can be replaced by adding almost 5% (by weight) of NHL (50nm). The outputs of this study can be interesting from a practical point of view since it was proved that the NHL has interesting functionality on the rheological performance of the binders.