Synergistic Utilization of Devulcanized Rubber and Rock Asphalt for Asphalt Modification

Abstract

Rock asphalt has gradually been recognized as a green and efficient asphalt modifier, however, the low-temperature performance and storage stability limited its utilization in asphalt pavement. To overcome the above shortcomings, this study aimed to synergistically apply devulcanized rubber powder (DRP) with American rock asphalt (ARA) for asphalt modification. Dynamic shear rheology (DSR), bending beam rheology (BBR) were conducted to evaluate rheological properties, road performance of CAM. Cigar tube test (CTT) was applied to assess storage stability of composite modified asphalt (CMA). Fourier transform infrared spectrometer (FTIR) and microscopic test (MT) were used to investigate the modification mechanisms. The results showed that CMA prepared by synergic utilization of DRP and ARA exhibit comparable storage stability, low-temperature performance and improved rutting resistance as SBS modified asphalt. ARA tended to cause aging problems of asphalt, but the addition of DRP effectively improved the anti-aging performance of modified binder blends, especially long-term aging resistance. The mixing of DRP, ARA and base asphalt is a physical process without chemical reactions. The ash in ARA caused poor storage stability but further improved dispersion and homogenous interface of DRP in asphalt.

Keywords: American rock asphalt, Devulcanized rubber, Composite modified asphalt, Performance evaluation, modification mechanism