ABSTRACT
Short-Term Aging (STA) of bitumen during hot mix production may affect its surface chemistry. The present study evaluates the effect of STA of bitumen on its compatibility with limestone aggregate using Surface Free Energy (SFE) concept. This study was conducted considering three different types of bitumen (one unmodified and two modified bitumen), and one aggregate type. STA of bitumen was simulated using thin-film oven. The present study used contact angle measurement for the determination of SFE components of bitumen and aggregate using sessile drop method. Further, Energy Ratio (ER) was calculated to evaluate the bonding potential of the unaged and aged binders with aggregate. STA may affect the cohesive and adhesive properties of bitumen. Test results showed decrease in the ER of CRMB60-limestone system after STA. However, improved ER for PMB40-limestone and VG30-limestone combinations were observed after STA. Hence, STA showed significant impact on the compatibility of bitumen–aggregate combinations. Keywords: Contact angle, Surface free energy, Energy Ratio, Short-Term Aging.
