Performance of reclaimed asphalt pavement rejuvenated with maltene

Abstract

Rejuvenating agents are considered desirable options for rejuvenating the reclaimed asphalt pavement (RAP) characteristics. However, some rejuvenating agents are not preferred due to their potential rutting damage when incorporated into the pavements, in addition to their poor practicality and durability for their medium to long-term usage. Based on these factors, this study aims to use the maltene as a rejuvenator. In phase I, maltene was extracted and characterised via several tests. In the next phase, a series of aged asphalt samples had been prepared with a range of maltene levels. Four physical tests were performed to determine the optimum dose of maltene. Next, the samples that contained an optimum percentage of maltene were analysed via rheological and chemical measurements. In the final phase, the performance of the rejuvenated asphalt mixtures was evaluated using several mechanical performance tests. Maltene was successfully extracted from a virgin asphalt (VA) using petroleum ether (with a ratio of 1 g asphalt: 5 mL petroleum ether). The gas chromatograph-mass spectrometer (GC–MS) spectra of maltene detected the right chemical compositions. Both physical and rheological traits of the blends containing 30%, 40% and 50% of aged asphalt were restored by incorporating 8%, 12% and 16% of maltene, respectively. The dynamic shear rheometer (DSR) and bending beam rheometer (BBR) analyses revealed an improvement in the performance of rejuvenated asphalts at both low and high temperatures. The Fourier transform infrared (FTIR) spectra of asphalt samples disclosed a decreasing in the chemical ageing index (CAI) and asphaltene content when the maltene was added to the asphalt. Meanwhile, the thermogravimetric analysis (TGA) indicated that the initial decomposition for rejuvenated asphalts was approximately close to VA. Other chemical and rheological traits of the rejuvenated asphalt disclosed its potency for practical applications. Accordingly, the mechanical characteristics results showed that maltene had been effective in mitigating the ageing effect of RAP. Marshall stability, indirect tensile strength (ITS), resilient modulus (MR), and creep stiffness modulus (CSM) decreased when maltene was included into the RAP mixtures as a result of reducing the stiffness of aged asphalt. Meanwhile, the flow, creep strain slope (CSS) and rutting depth increased by adding maltene. In general, all the rejuvenated asphalt mixtures results exhibited better values than VA mixtures. Besides, the RAP mixture with maltene exhibited higher coating capability, good stripping and disintegration resistance. Therefore, RAP mixtures incorporating appropriate maltene dosage as rejuvenator could be effectively used in road construction.