Abstract:
Crumb Rubber Modified Asphalt (CRMA) has many benefits such as increased rutting
resistance and reflective cracking resistance, but there are also major concerns that limits its
further application. These major concerns include low solubility of Crumb Rubber (CR) in
asphalt, high viscosity when it is incorporated in higher amounts and poor storage stability.
To tackle these limitations of CRMA, a hybrid approach was adopted in this study by
introducing Waste Engine Oil (WEO) in CRMA to create a balance between stiffness and
fluidity and to optimize the utilization of WEO along with CR to reduce the quantity of base
bitumen by increasing the contribution of waste materials. A laboratory-based study was
conducted to ascertain resilient modulus, Tensile strength Ratio (TSR), and permanent
deformation of modified asphalt mixtures. The chemical composition of waste materials was
determined using X-Ray Fluorescence test, and it was found that Zinc was found to be present
in abundance in CR, while sulfur was present in higher amounts in WEO as depicted by its
high concentration. It was observed that WEO can regulate the role of CR in asphalt because
it facilitated the swelling action of CR in asphalt as indicated by enhanced performance
properties. It was also found that the resilient modulus and rutting resistance was increased by
44% and 54% respectively as compared to control mixtures, whereas the moisture resistance
was increased by 7%. However, higher dosages of the modifier led to decrease in resilient
modulus, rutting resistance, and moisture resistance. Finally, the results of ANOVA and
Tukey’s analysis revealed that, at the confidence level of 95%, the modifier has a significant
influence on the performance indicators of modified asphalt mixtures.
