Investigation of the engineering properties of polymer modified bituminous stone mastic asphalt mixtures containing recycled cellulose acetate

In this study, the usability of cellulose acetate (SG) material recycled from cigarette butts as an alternative stabilizer instead of the traditionally used cellulose fiber (SL) was investigated in order to prevent the bitumen drainage problem frequently encountered in stone mastic asphalt (SMA) pavements. In addition, the effect of using SL at different dosages (0.1%, 0.2%, 0.3%, 0.4% and 0.5%) on mixture performance was examined. Within this scope, SMA specimens with and without fiber additives were produced using both neat bitumen (B) and Elvaloy RET + polyphosphoric acid (PPA) modified bitumen (1.6%, 1.7%, 1.8% Elvaloy RET + 0.2% PPA). Fiber-reinforced mixtures prepared with neat bitumen and unreinforced modified bitumen mixtures were considered as control specimens. In order to determine the effects of the modification, both conventional bitumen tests such as penetration and softening point, and Superpave binder tests such as dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were performed to observe the high- and low-temperature performance of short-term and long-term aged binders, and the hardness, fluidity and elasticity properties of the binders were examined. In SMA mixture design, the Marshall method was used to determine the optimum bitumen contents. The resistance to moisture was determined by conducting indirect tensile strength (ITS) and moisture damage (TSR) tests on the mixtures. The binder holding capacity of the fibers was evaluated using the Schellenberg bitumen drain down test, and the macrotexture properties of the mixture surfaces were measured by the sand patch method. Furthermore, the Cantabro abrasion test was applied to determine the raveling and stripping resistance of the mixtures. Finally, a cost analysis was carried out to determine the effect of different additive types and dosages used in the study on the mixture cost. As a result, while Elvaloy RET + PPA modification enhances the aging resistance of bitumen, SG fibers used at low dosages have been identified as a promising mechanical and economic alternative to SL fibers.