Effect of Warm Mix Asphalt on Aging of Asphalt Binders

Abstract

This paper evaluated the rheological and chemical properties of asphalt binders recovered from short-term and long-term aged foamed warm mix asphalt (WMA) and traditional hot mix asphalt (HMA). AASHTO R 30 was utilized to simulate the short-term and long-term aging of the laboratory-prepared asphalt mixtures. The dynamic shear rheometer (DSR) was used to characterize the rheological properties of the unaged and aged asphalt binders. Fourier-transform infrared (FTIR) spectroscopy was used to identify and quantify the amount of functional groups present in these binders. Gel permeation chromatography (GPC) was utilized to determine the molecular size distribution within these binders. The asphalt binders recovered from short-term and long-term oven aged HMA mixtures exhibited slightly higher G*/sinδ and G*sinδ values than those recovered from foamed WMA mixtures. The FTIR and GPC test results agreed with those obtained in the DSR. This indicates that foamed WMA mixtures undergo less aging than traditional HMA mixtures.