Synergetic effect in modification of oxidized road bitumens of different group composition

Abstract

The physico-chemical-rheological properties of the asphalt binder are critical to the long-term performance of the asphalt pavement infrastructure. The objectives of this investigation are to characterize the physico-rheological properties of unmodified pure and polymer-modified bituminous binders using rheological performance tests. The rheological properties of three pure oxidized bitumen, three SBS with sulfur-modified bituminous binders, and three bituminous binders modified with SBS+S+PPA were studied in this work. Various amounts of styrene-butadiene-styrene (SBS), sulfur (S) and polyphosphoric acid (PPA) modifiers were added to the pure binder for this purpose. The tested physical properties of the bituminous binder include traditional penetration and softening temperature. Group composition studies (saturates, aromatics, tars and asphaltenes; SARA) were respectively conducted to quantify the chemical composition and structural properties of pure oxidized bitumen. A dynamic shear rheometer (DSR) was used to evaluate the durability (PG) of virgin, thin film oxidized (RTFO-aged) and pressure vessel (PAV-aged) bitumens. The resistance to rutting and fatigue failure was evaluated using the test for creep recovery after repeated loading (MSCR). A bending beam rheometer (BBR) was used to study the low temperature properties of bituminous binders. All modifiers have been found to improve the high temperature properties of clean asphalt. In addition, these modifiers have not been found to have a significant effect on the low temperature continuous grade of the binders.