Analysis of the performance and mechanism of desulfurized rubber and low-density polyethylene compound-modified asphalt

Desulfurized rubber (DR) and low-density polyethylene (LDPE) were used to modify bitumen. The basic physical properties, rheological properties, chemical composition, thermogravimetric behavior, and morphological characteristics were determined and evaluated to analyze the performance and mechanism of DR and LDPE compound-modified asphalt. A series of experiments (e.g., conventional test methods, rotational viscosity, storage stability, and dynamic shear rheometer tests), Fourier transform infrared spectroscopy, thermogravimetric analysis–differential scanning calorimetry, fluorescence microscopy, and atomic force microscopy were conducted. The results revealed that DR-modified asphalt (DRMA) had increases in the penetration, ductility, softening point, and penetration index by 30.2, 22.3, 3.5, and 11.1%, respectively, over the crumb rubber-modified asphalt (CRMA). The compatibility between the asphalt and modifier is better for DRMA than for CRMA. These findings indicate that DRMA has a better pavement performance than CRMA. Furthermore, compared with DR-modified bitumen, LDPE inclusions increased the value of G*/sin δ by at least 75.9% and improved the thermal properties. Morphological observations confirmed that the DR/LDPE additives were better dispersed than crumb rubber and formed a more homogeneous phase separation in the asphalt. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48194.