Effect of Using Rejuvenators on the Chemical, Thermal, and Rheological Properties of Asphalt Binders (original) (raw)
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Rheological Characterization of Asphalt Binders Containing Rejuvenated Reclaimed Asphalt Pavement
Saudi journal of civil engineering, 2022
The use of reclaimed asphalt pavement (RAP) in freshly hot mixed asphalt (HMA) can save on material costs, preserve energy, and protect the environment. Employing limited amount of RAP in the production of asphalt mixes can result in similar performance as normal mixtures. However, adding more RAP can reduce the HMA's mixing efficiency and could make the asphalt mixture more susceptible to fatigue and low-temperature cracking. Vegetable oil can act as a rejuvenator and reduce the HMA deficiencies with a high RAP percentage. This study investigated the potential effect of two vegetable oils; namely soybean oil (SOY) and sunflower oil (SnF), as rejuvenators on the properties of asphalt binders that contain 40% of RAP binder. To determine the optimum dosage of the rejuvenators (SOY and SnF), the properties of the rejuvenated RAP binders were carried out by conducting the penetration, softening point, viscosity, dynamic shear rheometer (DSR), and bending beam rheometer (BBR) tests. The test results indicated that vegetable oils could provide better fatigue and low-temperature cracking resistance with acceptable rutting performance. Furthermore, it is observed that, for the abovementioned properties, the addition of the 6%SOY and 3%SnF were more feasible in restoring the 40RAP binder to its original properties.
Performance of Aged Asphalt Binder Treated with Various Types of Rejuvenators
Civil Engineering Journal
High demand for asphalt binders in road construction verifies the need of finding alternative materials through asphalt pavement recycling. This paper investigated the impact of different rejuvenators on the performance of an aged asphalt binder. Virgin Olive oil, virgin cooking oil, waste cooking oil, virgin engine oil, and waste engine oil were added to a 30/40 penetration grade aged asphalt binder at a fixed oil content of 4% for all types. The wet method was used to blend the rejuvenators and aged asphalt binder. The physical, rheological, and chemical properties of the rejuvenated asphalt binder were evaluated using several laboratory tests which include penetration, softening point, bleeding, loss on heating, storage stability, penetration index, ductility, viscosity, dynamic shear rheometer, and Fourier transform infrared spectroscopy. The outcomes of the physical properties showed that the olive, waste, and virgin cooking rejuvenators can restore the aged asphalt binder to a...
Impact of Asphalt Modifier Dosage on Modified Binder Rheology and Chemistry with Long-Term Aging
Asphalt modifiers/additives are increasingly used in pavement industry. Additives are commonly used as softeners to decrease the binder performance grade (PG), while polymer modifiers are usually used for heavy traffic applications to reduce permanent deformations. Recently, rejuvenators have been used in recycled pavement applications to reduce cracking susceptibility and as retarders to moisture damage. These modifiers can be derived from crude petroleum and sometimes from a bio-based feedstock. The origin of crude binder and modifier source affects the resulting binder-modifier chemical interaction. The inherent chemical variability affects the rheological performance of modified binders. It also impacts the aging potential of these binders and thereby affecting its long-term field performance. In this study, binders modified with softeners/rejuvenators at various dosages were evaluated for their performance under long-term aging. Rheological characterization of modified binders was determined using frequency sweep, linear amplitude sweep, and low temperature performance with parameters such as Glover-Rowe, R-value, crossover frequency, ∆Tc, while the chemical characteristics were determined using Fourier transform infrared spectroscopy (FTIR), and thin layer chromatography and flame ionization detection (TLC-FID). An optimum dosage of the rejuvenator studied was recommended to maximize performance of the modified binder.
Effect of long-term ageing on the rheological properties of rejuvenated asphalt binder
Road Materials and Pavement Design, 2019
Recycled asphalt products are increasingly being used in asphalt concrete pavements to improve pavement sustainability. Asphalt recycling, while it is undoubtedly an environmentally sustainable practice, includes asphalt binder that is already oxidised. Aged binder is highly brittle and becomes a driving factor for cracking related distresses. As a result, use of recycled materials can have a significant negative impact on pavement performance, specifically when used in increased amounts and cold climatic conditions. In order to improve the performance of asphalt concrete mixtures with recycled materials, rheological properties are changed by adding rejuvenators. In asphalt industry, rejuvenators are either used at an initial virgin state of the binder to reduce mix ageing or blended at a later stage in recycled materials to improve the properties of aged mix. The current study focuses on evaluating the performance of asphalt mixes prepared by blending rejuvenators in already aged binders. Virgin PG 64-22 binder was aged using RTFO and PAV and further mixed with three different kinds of rejuvenators namely Hydrolene 90T, Kendex@ME, and Hydrogreen S at 3%, 6% and 9% by weight of the total binder. To study the behaviour of rejuvenated asphalt binder samples over a long period of time, mixed asphalt samples were then aged for 5, 10, 15, 20, 40 and 60 h in the PAV. Frequency sweep tests were conducted to characterise binder rheology, and parameters such as Glower-Rowe, crossover frequency, and Superpave rutting parameter were calculated. A comparative analysis was carried out to determine the impact of increased ageing and rejuvenator addition in varying amounts on the performance of asphalt mixes. A significant correlation was found out between the types of rejuvenator used in different dosages and the level of ageing in the asphalt binder.
2016
Hot in-place recycling (HIR) preserves distressed asphalt pavements while minimizing use of virgin binder and aggregates. The final quality of an HIR mixture depends on characteristics of the original binder, aging of the pavement surface during service, and whether or not new binder or rejuvenator was added to the mixture. An HIR mixture should maintain desired properties for additional service periods, making asphalt binder modification inevitable. Asphalt binder modifications in HIR are commonly done by adding an asphalt rejuvenating agent (ARA). However, ARA may adversely affect the qualities of new HIR and potentially fail to improve the quality of the final surface. The objective of this research was to investigate the effects of rejuvenation on HIR performance characteristics by assessing critical performance indicators such as stiffness, permanent deformation, moisture susceptibility, and cracking resistance. A two-step experimental program was designed that included mechanical property measurements of the HIR mixture and rheological properties of the extracted binder. The level of mixing occurring between new and aged binder with ARA was also investigated. HIR Samples were obtained from three Kansas Department of Transportation projects, and Hamburg wheel-tracking device, dynamic modulus, flow number, Texas overlay, thermal stress restrained specimen, and moisture susceptibility tests were conducted on mixtures with and without ARA. Rheological studies on the extracted binder included dynamic shear rheometer and bending beam rheometer tests. The miscibility of new and aged binder was investigated using scanning electron microscope (SEM) images, energy dispersive X-ray spectroscopy (EDXS), and the exudation droplet test (EDT). Study results showed significant variability in the mechanical performance of HIR mixtures, which was attributed to the variability of binders as observed in EDT, SEM and EDXS studies. Life cycle cost analysis (LCCA) showed that HIR is an economic maintenance alternative for asphalt projects in Kansas. LCCA results exhibited that pavement design strategies with HIR activities will result in alternatives with lower net present values when compared to alternatives without HIR maintenance activities.
Effect of asphalt rejuvenating agent on aged reclaimed asphalt pavement and binder properties
2016
Hot in-place recycling (HIR) preserves distressed asphalt pavements while minimizing use of virgin binder and aggregates. The final quality of an HIR mixture depends on characteristics of the original binder, aging of the pavement surface during service, and whether or not new binder or rejuvenator was added to the mixture. An HIR mixture should maintain desired properties for additional service periods, making asphalt binder modification inevitable. Asphalt binder modifications in HIR are commonly done by adding an asphalt rejuvenating agent (ARA). However, ARA may adversely affect the qualities of new HIR and potentially fail to improve the quality of the final surface. The objective of this research was to investigate the effects of rejuvenation on HIR performance characteristics by assessing critical performance indicators such as stiffness, permanent deformation, moisture susceptibility, and cracking resistance. A two-step experimental program was designed that included mechani...
Materials, 2022
Reclaimed asphalt pavements (RAP) provide economic and environmental benefits. In recent decades, their use has increased, but rheological properties are affected by RAP aging, increasing stiffness, cracking, and susceptibility to water. To counteract these effects, rejuvenating agents are used, but they must be properly dosed to design quality mixtures. Therefore, different binders were analyzed, including virgin binder (VBB), binder modified by SBS polymer (MB), AC-RAP, binder softened using a rejuvenating agent, and binders softened with doses (15%, 30%, and 45%) of AC-RAP. The rheological properties were evaluated by dynamic shear rheometry (DSR) and beam-bending rheometry (BBR) tests, while the linear amplitude sweep (LAS) test was used to measure fatigue cracking and the multiple stress creep recovery (MSCR) test was used to measure rutting. A mixing chart was constructed based on a high temperature AC-RAP to satisfy the performance grade (PG 76-22). The results showed that so...
Effects of rejuvenator on performance-based properties of rejuvenated asphalt binder and mixtures
Construction and Building Materials, 2007
Firstly, the performance-based properties of rejuvenated aged asphalt binders, i.e., the blends of aged binders containing a rejuvenator at various percentages, were investigated under high, intermediate and low temperatures. The tests were conducted on the blends at three stages as follows: no aging, rolling thin film oven (RTFO) residuals and as well RTFO + pressure aging vessel (PAV) residuals through dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. Optimum concentrations of the rejuvenator needed for the blends to reach a target PG grade were obtained from the blending charts of the rejuvenated aged binders in terms of performance properties. The rejuvenator is a soft binder containing a low asphaltene content of 2 wt%. Secondly, selected performance-based properties were conducted on hot mix asphalt (HMA) using the rejuvenated aged binder and a virgin HMA as a control mixture. Results showed that the rejuvenator affected significantly the performance-based properties of both the rejuvenated aged binders and the mixtures containing the rejuvenated aged binders. It was possible to get optimum concentrations of the rejuvenator using the blending charts so that the rejuvenated binders reach a target PG grade. The mean value of the concentrations was proved to be more reliable through the performance-based properties of the mixtures if it is used for a design value for recycling. The properties of the asphalt paving mixtures with the rejuvenated binders were even improved or in the same level as the properties of the virgin mixtures.
Aging Influence on Rheology Properties of Petroleum-Based Asphalt Modified with Biobinder
Journal of Materials in Civil Engineering, 2014
This paper aims to investigate the viability of using swine waste binder to improve the rheological properties of bituminous asphalt binder. Due to rising bituminous asphalt binder costs, diminishing reserves of crude oil from which asphalt binder is derived, and the gradual paradigm shift toward more environmentally friendly and energy efficient hot-mix asphalt (HMA) mixtures, the asphalt pavement industry is exploring different sustainable alternative binders. Biobinder has the potential to partially or fully replace typical crude-based asphalt. In this paper, biobinder from swine manure is produced by thermochemical liquefaction process at 380°C and 40 MPa (approximately 400 atm) pressure in the absence of oxygen. A Superpave PG 64-22 is then modified with 5% biobinder by total weight of asphalt binder to produce the biobinder. Samples of the base asphalt binder (nonmodified PG 64-22) and samples of asphalt modified with biobinder are characterized by running the Superpave rotational viscosity (RV), dynamic shear rheometer (DSR), and the bending beam rheometer (BBR) tests. Furthermore, Fourier transform infrared (FTIR) spectroscopy investigations were used to validate the chemical bond initiations that caused changes in stiffness and viscosity of the asphalt modified with 5% biobinder from those of base asphalt binder (PG 64-22). The modification resulted in 27% decrease in viscosity of the base binder. The rolling thin film (RTFO)-aged samples of modified binder experienced a 28.9% decrease in average viscosity change when compared with the RTFO-aged samples from the base binder. Additionally, the pressure aging vessel (PAV)-aged samples of modified binder experienced a 62.9% decrease in average viscosity change when compared with the PAV-aged samples of base binder. The rotational viscosity results proved that the addition of biobinder (swine waste asphalt binder) can reduce the viscosity of the asphalt binder. Furthermore, the modified binder had lower complex moduli and phase angles compared with the base binder (based on DSR results). The BBR results indicated that biobinder had the potential to improve the thermal cracking performance of conventional asphalt binders by reducing the creep stiffness and increasing m-value. The BBR results proved that the modification of the PG 64-22 induces a one grade jump on the lower temperature side. The functional groups in typical petroleum-based asphalt binders remained unchanged after the addition of the biobinder to the PG 64-22 binder. Additionally, the FTIR spectra showed that addition of biobinder decreased the stiffness of the PG 64-22 binder through the reduction in molecular carbonyl and sulphoxide bond chains at high temperature. This research investigation provides useful rheological and morphological guidance on the use of swine waste binder as an asphalt binder and mixture modifier.
Aging of Rejuvenated Asphalt Binders
Advances in Materials Science and Engineering, 2017
An important concern that limits the RAP content in asphalt mixtures is the fact that the aged binder that is present in the RAP can cause premature cracking. Rejuvenators are frequently added to high RAP mixtures to enhance the properties of the binder. There is no existing method to predict the longevity of a rejuvenated asphalt. This study investigated the aging of rejuvenated binders and compared their durability with that of virgin asphalt. Various samples with different types and proportions of RAP, virgin binder, and rejuvenator were aged by RTFO and three cycles of PAV. DSR and BBR tests were conducted to examine the high-temperature and low-temperature rheological properties of binders. Results indicated that the type and dosage of the rejuvenator have a great influence on the aging rate and durability of the binder. Some rejuvenators make the binder age slower, while others accelerate aging. These observations confirm the importance of evaluating the long-term aging of rec...