Comparative Study of Rheological Behavior of Modified Binders for High-Temperature Areas

The failures of the bituminous pavements are not only due to increase in traffic but also due to extreme climatic conditions prevailing in the country. There are very high and very low pavement temperatures that exist during different seasons of the year. Thus, climatic conditions play an important role in selecting the type of materials to be used in road construction. In order to increase the life of bituminous pavement, quality of bitumen needs to be enhanced. To achieve the improvement of binder, it is necessary to add the polymers to bitumen. In this study, two types of polymer — ethylene vinyle acetate (EVA), a plastomer, and linear styrene-butadiene-styrene (SBS), an elastomer — and crumb rubber (CR) were used. The changes of rheological properties of 60/70 grades bitumen modified with different percentages of CR, EVA, and SBS (3–9%) were studied. The rheological properties of the bituminous binders in terms of their complex modulus (G∗), stiffness and overall resistance to deformation, storage modulus (G′), binder elasticity, loss modulus (G″), viscous behavior and phase angle (δ), and viscoelastic behavior were measured by using dynamic shear rheometer (SR5 asphalt rheometer). Testing was performed at higher temperatures ranging from 46 to 82°C in increments of 6°C at a frequency of 10 rad/s in the range from 0.1 to 100 rad/s before and after aging. It was observed that the rheological properties of bituminous binders had changed after modification. There is an improvement in rheological properties of the neat bitumen after mixing with modifiers.