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This study seeks to examine the physical and high-temperature rheological performance of crude palm oil (CPO)/tire pyrolysis oil (TPO) composite asphalt to develop a more sustainable bio-rubberized asphalt (BRA) binder. The study uses the penetration, softening point, and dynamic viscosity tests to evaluate binder consistency and dynamic shear rheometer (DSR) tests to determine the linear viscoelastic properties before and after short-term aging. The nonlinear viscoelastic properties of modified asphalt were determined using the multiple stress creep recovery (MSCR) test. Results showed that the substitution of 20 asphalt with tire pyrolysis oil-modified bio-asphalt retained or enhanced the asphalt grade performance at high temperatures. All BRA binders have a higher aging resistance than the base asphalt. The MSCR results showed that, relative to all tested binders, the BRA binder containing 5 CPO and 5 TPO has optimal non-recoverable creep compliance (Jnr) and percentage of recovery (R) with a performance close to PG64H compared to the PG64S performance grade of the base asphalt. Overall, the findings of this study indicate that the incorporation of CPO/TPO in asphalt is suitable for producing bio-rubberized asphalt containing 20 recycled waste rubber and bio-oil and improves the high-temperature properties of asphalt to a certain extent. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

Aging of asphalt binders occurs when oxidation takes place in the binder, and this in turn causes the deterioration of pavement. This paper presents the effect of aging on 60/70 penetration grade asphalt binder incorporated with polyurethane (PU) in terms of chemical interaction, morphological and wettability properties. The chemical characteristics of the base binder (BB) and polyurethane modified binder (PUMB) was evaluated using Fourier Transform Infrared while the morphological properties were analyzed using Raman Spectroscopy. Contact angle test was performed to determine the wettability of PUMB over the aggregates. In this study, the BB is modified with 3 wt% PU. Rolling Thin Film Oven and Pressure Aging Vessel tests were conducted to simulate the short-term aged and long-term aged of the samples. Results showed that the addition of PU to BB has no significant effect on the chemical interaction in the modified binder before and after aging. The incorporation of PU and the aging of modified binder resulted in a reduced bee-structure in the BB, which in turn reduced the wettability of the asphalt binder. The incorporation of PU to the BB improved the oxidative aging of the binder.

This paper discusses the utilization of Response Surface Method (RSM) statistical tool to determine the optimal amount of polyurethane (PU) for modifying 80/100 penetration grade bitumen. Central composite design (CCD) was used to develop an experimental design matrix where bitumen and PU are designated as the factors while penetration, softening point and viscosity are designated as the response. Numerical analysis of polyurethane modified bitumen (PUMB) shows that the optimal amount of PU in the modification of the bitumen is 5%. Verification of the chosen model shows that it is in consistent with the experimental value since the percentage error is less than 5%. Result of the consistency test shows that the addition of 5% PU resulted in higher penetration and viscosity values but lower softening point value, which in consequent improve bonding strength as the flow of bitumen is reduced.

Asphalt binders have been modified with various additives and modifiers as an effort to fulfil the demand for high-performance pavements. Therefore, this study aims to investigate the engineering and leaching properties of 60/70 penetration grade asphalt binder modified with polyurethane (PU) and Cecabase additives for warm-mix asphalt (WMA) application. Measurements of the physical properties of unmodified and modified asphalt binders were made via penetration, softening point, ductility and viscosity tests. The binder-aggregate adhesivity was established by performing the Vialit test while X-Ray Diffraction (XRD) analysis was conducted to determine crystallinity of the binder. Differential Scanning Calorimetry (DSC) was used to determine thermal behavior of the asphalt binders. Synthetic precipitation leaching procedure (SPLP) test was carried out to determine the mobility of organic and inorganic elements present in the binder. PU as modifier and Cecabase as the WMA additive-enhanced binder stiffness. In contrast to Cecabase, the addition of PU increased viscosity of the binder at varying temperatures. PU also enhanced the interfacial adhesion between the binder and the aggregates. The XRD patterns showed that the incorporation of PU and Cecabase has no influence in the crystalline structure of the asphalt binders. Both PU and Cecabase have the ability to improve the workability of the binder at low temperature. The incorporation PU and Cecabase to the asphalt binder showed insignificant shift of the Tg and Tm. SPLP test results indicated that the amount of heavy metals leached out from the asphalt binder samples have no adverse effect on the environment and also did not exceed the standard for drinking.