Neat Binder Research Articles

EVALUATION OF BITUMINOUS MIXES WITH EPOXY-MODIFIED ASPHALT BINDERS

Road surfaces have long been made with bituminous mix because of its low cost and versatile applications. However, environmental variables, traffic loads, and ageing frequently affect its endurance. Many additives have been introduced to overcome these problems, and epoxy resin has shown great promise. This study evaluates bituminous binder and bituminous mixes with different percentages of epoxy modification. Epoxy asphalt binder's (EAB) rheological properties were described. Following that, an evaluation was conducted on the engineering properties of an epoxy asphalt mixture (EAM). The results demonstrated that the rheological properties of EAB outperform those of neat binders. Furthermore, the outcomes demonstrated that EAM had better moisture damage performance in terms of static immersion test and retained Marshall stability test than the conventional hot dense graded bituminous mixes. According to the results, the ideal content for both VG 30 and VG 40 binders is 2% epoxy modification. Out of all the mix permutations, bituminous mixes with 2% epoxy modification yielded the best results. Comparing blends with control mixes or unmodified bituminous mixes, on the other hand, revealed a lower resistance to moisture damage than mixes with 3% epoxy modification with both binders. The study concludes that epoxy resin can significantly improve the performance and longevity of asphalt concrete roadways, offering benefits to the road construction industry.

Research on performance variations of different asphalt binders results from microwave heating during freeze-thaw cycles

Microwave heating (MH) as a sustainable pavement maintenance method can effectively repair the cracks caused by freeze-thaw (FT) damage. However, binders' properties may be weakened during this process then reduces the pavement life. For this purpose, this work aims to investigate the performance changes of neat binders (Nb) and high-viscous binders (Hb) during FT and MH. The physicochemical, rheological, and deformation properties are investigated after FT and MH. Results indicate that asphalt binders become harder and lead to an increase in carbonyl index (CI) and sulfoxide index (SI) after FT. MH has a limited damage level for binders especially for Hb, causing a slight increase in CI and SI, compared to binders after FT. Polymers play an important role in the viscoelastic responses of asphalt binders. Changes in viscoelastic properties of Nb mainly result from the binder damage of FT and MH, while viscoelastic changes of Hb are mainly due to the damage of polymers. This different damage mechanism causes Hb to show better resistance compared to Nb, which is reflected in modulus and phase angle. BBR tests indicate that MH can further deteriorate the damage of both binders, but Hb shows a lower performance decline compared to Nb, and it is recommended to conduct MH at the region with a minimum temperature above −12 °C. MSCR results reveal that FT and MH can improve the rutting resistance of Nb due to the hardening phenomenon after damage, and reduce the elastic stability of Hb due to the damage to polymers. In summary, Nb is sensitive to MH, its performance can be further damaged after MH. Hb has better resistance to MH, its properties do not further deteriorate, so Hb is more applicable to MH.

Assessing the Performance of Recycled Asphalt Mixtures Using Rejuvenators

After serving their intended purpose, traditional asphalt pavements are destroyed and dumped across the neighboring fields in Pakistan, affecting the natural environment. Only 15% of the old asphalt material has been recycled on the Motorway (M-2) near Shekhupura. Thus, the current study was intended to increase the amount of recycled asphalt, utilizing waste engine oil (WEO), waste cooking oil (WCO), and waste brown grease (WBG) as rejuvenators. Therefore, the asphalt mixture containing 50% recycled materials, rejuvenated with 5%, 10%, 15%, 20%, and 25% WEO, WCO, and WBG, respectively, were investigated. The asphalt samples for Marshall Stability, indirect tensile strength, and rut resistance were prepared and tested as per ASTM D1559, ASTM D979, and ASTMD8360, respectively. The results showed that WEO, WCO, and WBG of 15% and 20%, respectively, are best for equating the properties of recycled binder to those of neat binder, except for ductility characteristics. The results also demonstrated that, in comparison to the traditional asphalt mixture, asphalt mixes with 50% recycled materials performed significantly better in terms of Marshall stability at 15% utilization of WEO, WCO, and WBG, respectively. Additionally, it is established that recycled asphalt mixture, at WEO of 15%, displayed equivalent rut resistance to virgin asphalt mixture. The results of this study will help recycle old asphalt materials for practical engineering purposes, lowering the dependence on natural resources and benefiting the environment.

Evaluation of Linear Amplitude Sweep data analysis techniques and failure criteria for High Polymer-Modified binders

High Polymer Modified Binders (HiPMBs) have gained attention for their resilience to environmental and traffic stressors, yet their fatigue cracking resistance remains insufficiently explored. Even though the Linear Amplitude Sweep (LAS) test is an AASHTO standardized procedure, various data analysis techniques and failure criteria can be found in the literature. It is unclear whether they produce divergent results and whether any of them provide better insights into bitumen behavior. The research showcased in this paper aimed to assess the factors affecting the evaluation of HiPMBs' fatigue life through the LAS test. Additionally, asphalt concrete was produced with bitumen previously tested and subjected to Push-Pull (PP) fatigue cracking evaluation for direct comparison. Results show significant differences between analysis methods, regardless of the failure criteria applied. The methods that rely on the Viscoelastic Continuum Damage (VECD) analysis were affected by the inaccuracy of the material integrity function fitting. The failure criterion significantly impacts the ability to detect the benefits of the high polymer content, which becomes increasingly noticeable for failure criteria different from those suggested in the AASHTO specification. Meanwhile, the Fatigue Resistance Energy Index (FREI) approach has a great advantage of not being tight to the VECD formulations and was able to capture the differences between the Neat Binders (NBs) and the HiPMBs. As for the corresponding binders' performance on the HMA level, similarities in the ranking were noticed; however, no full agreement was recognized.

Investigation of the Performance of Bio-Oils from Three Different Agricultural Wastes as Rejuvenators for Recycled Asphalt

The aim of this study was to investigate the possibility of using bio-oil obtained from pine cones, olive mill pomace, and wheat straw as rejuvenators for the reuse of aged asphalt binders. Additionally, the biomass used for bio-oil production was selected from waste materials. Therefore, it makes great contributions to both the environment and the economy. B50/70 bitumen was selected as the neat binder. The bio-oils used in the study were obtained as a result of pyrolysis. Bio-oil rejuvenators at 5%, 10% and 20% by the weight of the binder were added to the aged binder obtained from recycled asphalt mixtures to obtaine bioregenerated asphalts. The physical and rheological properties of bioregenerated asphalts were investigated and not compared on neat and aged binders through penetration, softening point, rotational viscometer and dynamic shear rheometer tests. In addition, the effects of temperature and biooil content on complex modulus properties were examined using response surface methods. It was foud that while the bio-oils increased the penetration values of the aged binders, they also decreased the softening point and viscosity values. The bio-oils significantly modified rutting resistance of the aged binder. The addition of bio-oil improved the viscous components and can rejuvenate the viscoelastic properties of aged asphalt binders to that of almost the original level. In addition, response surface methods results showed that the interactions between both independent variables were effective. Finally, high coefficient of determination (R2) values indicated good agreement between the actual and predicted values. It was recommended as a result of the study that 20% concentration of bio-oil should be used to rejuvenate the aged asphalt binder for reuse in pavement construction.

The effect of incorporating magnetic fly ash in asphalt binders with respect to permanent deformation and fatigue

The search for efficient and environmentally viable materials to improve the quality and durability of asphalt binders used in roadways has been growing in recent years. This is especially true giving the increase in the volume and magnitude of traffic loads, as well as the changes in the earth's temperature that cause frequent pavement distresses, such as permanent deformation and fatigue. In this context, the objective of this work is to evaluate the potential of magnetic particles from fly ash, as a residual resource with high added value and low-cost raw material for modifying asphalt binders. Magnetic particles were incorporated into the asphalt binder at 2%, 4%, 6% and 8%, content by weight. The materials were characterized by chemical, empirical and rheological tests, specifically the Multiple Stress Creep and Recovery and the Linear Amplitude Sweep test. X-ray Fluorescence data revealed silicon, aluminum and iron as the main elements present in the fly ash, as well as the increase in iron concentration after magnetic separation in the magnetic particle sample. A homogeneous dispersion of magnetic particles in the asphalt binder observed by Scanning Electron Microscopy and shifts in infrared bands characteristic of iron (ca. 450 cm-1) and of asphalt binder (ca. 1456 cm-1) clearly indicated a significative interaction between the magnetic particles and the asphalt binder. The rheological results indicated that the incorporation of particles provide better performance to the binder in terms of both permanent deformation and fatigue. The modified binders were less susceptible to permanent deformation than the neat binder, and this is reflected in the increase in adequate traffic levels, moving from standard traffic to heavy traffic at a temperature of 64 °C. This economical, easy, and sustainable approach to using magnetic particles in hot asphalt binders can contribute to producing asphalts that are more efficient with changes in temperature and traffic.

Qualitative Evaluation for Asphalt Binder Modified with SBS Polymer

Solutions for safer, more durable infrastructure are required in light of increasing traffic and severe weather in Iraq. The most significant road conservation and maintenance challenges are the pavement's low resistance to dynamic loads and short service life. As a result, vast sums of money are spent annually to enhance the road service capacities in Iraq. Thermoplastic electrometric polymers for bitumen modification create long-lasting, cost-effective roadways. This study aims to determine how the mechanical properties of neat asphalt binder change when styrene butadiene styrene (SBS) is added as a modifier. The current research investigates adding three percentages of SBS (3, 5, and 7% of the weight of bitumen). Both neat and polymer-modified bitumen (PMB) were subjected to a series of physical laboratory and Superpave tests, including a dynamic shear rheometer tester (DSR) and a storage stability test. In addition, a chemical analysis test was conducted to identify any change in the neat binder chemical composition due to the addition of SBS polymer. The results indicated that 5% of SBS polymer was the optimum addition percentage to the local asphalt in Iraq. Additionally, it reduced the susceptibility of bitumen to temperature changes and enhanced its characteristics in all laboratory tests. The obtained PMB significantly improved rutting and fatigue factors compared to the neat asphalt binder. Based on the DSR tester and the storage stability test, the ratio of 5% SBS met the requirements of class PG76-10, used in the central and southern governorates of Iraq. Using SBS polymer on the surface course in Iraq reduces road damage due to the scorching summer sun, reduces the likelihood of rutting and fatigue cracking, and works well in hot regions, resulting in roads that last longer, provide comfortable riding, and require less maintenance.

Effect of recycled vegetable oil on the performance of nanomarl-modified asphalt mixtures

In response to the demand for a greener approach to pavement infrastructure and the economic benefits associated with alternative materials, the modification of neat binders has been a consistent focus. This research aimed to enhance the characteristics of asphalt binders and mixtures by incorporating recycled vegetable oil (RVO) and nanomarl. RVO was added to 60/70 penetration bitumen at concentrations of 1%, 3%, and 5% by weight, while nanomarl was kept constant at 5% by weight of the bitumen. Various physical, rheological, and microstructural properties of the modified binders were evaluated, including penetration, softening point, viscosity, rutting resistance, fatigue resistance, creep, stiffness, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Furthermore, the moisture susceptibility and rutting resistance performance of asphalt mixtures incorporating these modified binders were investigated through analyses of tensile strength ratio and Hamburg wheel tracking. The test results revealed that the incorporation of RVO in bitumen led to a gradual increase in the penetration value of the modified bitumen. Simultaneously, the softening point and viscosity of the modified bitumen decreased, indicating that the addition of oil rendered the modified bitumen softer. However, the inclusion of nanomarl in RVO-modified bitumen improved its viscoelastic behavior and positively influenced its rheological properties under both unaged and aged conditions. Specifically, the addition of 5% nanomarl resulted in reduced penetration value, increased softening point, viscosity, rutting resistance, fatigue resistance, creep stiffness, and improved relaxation behavior at low temperatures. The most favorable outcomes were observed when incorporating 1% RVO with 5% nanomarl. Moreover, SEM and FTIR analysis demonstrated successful blending of the additives into the bitumen, without any evidence of phase separation. This indicates a homogeneous distribution of the additives within the bitumen matrix.Practical application: The modification of bitumen with waste or recycled oils for the production of asphalt mixture has been successfully studied in numerous researches. However, this study introduces a novel approach by synergistically combining recycled vegetable oil (RVO) modification with the incorporation of nanomarl particles into asphalt mixture. The innovation aspect lies in the integration of two sustainable and environmentally friendly components, RVO and nanomral, to enhance asphalt performance. The findings offer a blueprint for incorporating sustainable materials and approaches in road construction projects. Pavement engineers can adopt the use of RVO modification and nanomarl particles to create longer-lasting and environmentally friendly asphalt pavements. In regions with challenging climatic conditions, the use of this modified asphalt can lead to improved infrastructure resilience. Roads built with these materials can better withstand temperature fluctuations. The integration of RVO and nanomarl particles offers improved performance, cost-effectiveness, reduced environmental impact, and also opens avenue for further exploration and optimization of asphalt mixtures incorporating innovative additives.

Multiscale evaluation of asphalt binder rejuvenation dosing and efficacy

The final composition of asphalt binder in an asphalt mix can vary depending if it is a neat, virgin binder, or a blend of neat binder with reclaimed asphalt pavement (RAP), modifiers, and/or rejuvenators. As recycling of asphalt concrete becomes more commonplace worldwide, so too must be the use of chemical rejuvenators which can restore the original properties of the associated asphalt binder, contributing to the performance and therefore sustainability aspect of this material. In this context, this work aimed to evaluate the influence of rejuvenation in different proportions of aged and unaged binder, as well as the best way to dose rejuvenators, taking into consideration aspects that go beyond the Superpave Performance Grading characterization of binders. In the first phase of this study, when rejuvenator contents based on low PG recovery were proportionally added to different aged/unaged binder blends, it was observed that restoration of ductility and strength of the rejuvenated aged binder was limited. However, when an additional cycle of aging was applied to simulate the new service life of recycled material, the rejuvenated recycled material generally performed better than unrejuvenated recycled material. This long term effect can better differentiate the performance of different rejuvenators. Afterwards, the dosing procedure was investigated using an extensive range of dosages. An optimal dosage determination approach was developed and verified by means of the rejuvenation of aged asphalt mixtures from the rheological, mechanical, and chemical perspectives. Finally, the differences between laboratory-aged binder and laboratory-aged mixtures when rejuvenators are used was investigated, and it was determined that the mechanisms of rejuvenation at the two scales are not completely alike. Key findings also include the importance of re-aging asphalt binder blends before testing when a rejuvenator is used and the dominance of unaged binder within binder blends with limited replacement with recycled asphalt. Overall, this work opens the door to future studies of rejuvenation of asphalt using different approaches than those which have been conventionally used, including consideration of amount of replaced binder, using nonlinear viscoelastic characterization, fundamental chemical studies, and the method of addition based on mixture versus binder scale studies.

Improving the performance and rheological properties of RAP binders using gilsonite/nanoclay and softer binder

One of the ways to improve the performance of asphalt containing RAP is the use of a modified softer binder, which can enhance the rheological and performance characteristics. In this study, to improve the rutting and fatigue properties of reclaimed asphalt binder (RAB), a softer binder containing vacuum tower bottom (VTB) and Gilsonite/Nanoclay (Gil/Nc) composite were used. In this regard, the behavior of modified RAP binders has been controlled and analyzed using physical, rheological, and performance criteria from a laboratory test and ANOVA statistical method. The three scenarios designed in this research included a neat binder, RAB containing a soft binder, and RAB containing Gilsonite and different percentages of Nanoclay. The results showed that the modified softer binders (MSB) due to the presence of a high percentage of asphaltene in Gilsonite cause a quasi-solid behavior with a lower decay rate against plastic strains and improve rutting resistance at high PG temperature. The results of the BBR test showed that despite the negative effect of the Gil/Nc combination on the low-temperature behavior, the presence of VTB containing significant aromatic compounds compensated this problem to a large extent. The simultaneous results of DSR and BBR tests showed that RAB25_Gil/Nc6, RAB50_Gil/Nc6, and RAB50_Gil/Nc3 binders with useful temperature ranges of 97.5 °C, 97.1 °C, and 94.2 °C have the best performance. The outcomes of the LAS test showed that MSB increases fatigue life and reduces the probability of cracking of RAB. MSB containing Nc6 performs better due to the formation of an elastic network due to the strong interaction between nanoparticles and functional groups of the binder. The statistical analysis based on the laboratory results showed that the changes in dosage of the Nc and RAB have a significant impact on the performance characteristics. According to technical and functional considerations, MSB_Gil/Nc6 combination was proposed for modification of the binder containing RAB50.

Rheological Behaviors of Waste Polyethylene Modified Asphalt Binder: Statistical Analysis of Interlaboratory Testing Results

Abstract This article investigated the effect of waste polyethylene (PE) on the modified asphalt binders’ rheological behavior from a statistical point of view. The interlaboratory testing results from the RILEM Technical Committee 279 Valorization of Waste and Secondary Materials for Roads Task Group 1 were used for this purpose. First, an unaged 70/100 penetration graded neat binder was selected as the reference material. Next, a single 5 % content of waste PE additives (PE-pellets and PE-shreds) was mixed with a 95 % neat binder to prepare two PE modified binders. Then, dynamic shear rheometer–based temperature-frequency sweep tests were performed over a wide range of temperatures and frequencies to evaluate the rheological properties of these three binders. Different rheological behaviors were observed in the isochronal plots at high temperatures. Based on a reproducibility precision requirement proposed for phase angle, 28°C was set as the transition temperature across the rheological behaviors. Next, according to the three rheological behaviors defined in a previous study by the authors, statistical analysis was introduced to identify sensitive rheological parameters and determine the thresholds. Results indicate that the phase angle measured above 28°C and 1.59 Hz can be used as a sensitive parameter to discriminate the three rheological behaviors of PE modified binders. The thresholds among different behaviors were also calculated as an example for phase angle measured at the highest common testing temperature of 70°C. Additional experimental evaluations on more types of PE modified binders, especially at intermediate and high temperatures, are recommended to better understand their influence on the rheological behavior of PE modified binders.

Evaluation of Aging Evolution of Olive Pomace–Modified Asphalt Binders under Natural Weather Aging Conditions

Abstract The natural weather aging test (NWAT) for asphalt binders is an essential benchmark aging test used to investigate the aging evolution of asphalt binders under actual weather conditions. This study assessed the aging rates of olive pomace–modified asphalt binders and the control neat binder under NWAT. Instead of aging days, weather factors were proposed as metrics to correlate with the aging evolution of the rheological properties of asphalt binders. The test results showed that the olive pulp–rich fraction-modified asphalt binders after the rolling thin-film oven (RTFO) test had lower aging susceptibility than the RTFO-aged control binder. The RTFO-aged binders exhibited lower aging rates than the corresponding unaged asphalt binders under NWAT. The sums of weather indexes such as the sum of the daily maximum ultraviolet index are rational field metrics to correlate with the rheological aging properties of natural weather–aged asphalt binders. Caution shall be taken when using aging days to interpret the aging rates of asphalt binders under NWAT.

Fatigue Performance of Recycled Asphalt Mixtures: Viscoelastic Continuum Damage Approach and Cost Analysis

This study aims to evaluate the fatigue phenomenon in recycled hot asphalt mixture for an asphalt surface layer. Eight mixtures were evaluated in the laboratory, and the samples were divided into two major groups: four mixtures containing neat binder and RAP from source 1 (RAP with neat binder) and four mixtures containing SBS-modified binder and RAP from source 2 (RAP with SBS-modified binder). The levels of RAP incorporation were 0%, 10%, 20%, and 30% in relation to the total weight of the mixtures. The mixtures followed the Marshall mix design methodology. The results indicate that mixtures with polymer-modified binder presented better performance, whereas the addition of RAP slightly decreased the resistance to fatigue cracking. In terms of economic analysis, the use of RAP, for all cases, leads to a reduction in production costs due to the reduction of the binder and aggregate added, with savings of up to 14.1% in the case of 30% of RAP for the SBS binder. When evaluating the economic impact of inserting RAP and its relationship with fatigue performance in the long term, it can be observed that the type of binder added impacts the results: mixtures with SBS binder present economic gains within acceptable quality parameters up to 30% RAP insertion; for mixtures with neat binder, the percentage of up to 10% RAP is advantageous.

Effect of Stress Levels and Temperatures on Stress Recovery of Asphalt Binders

Abstract: HMA's rut resistance comes from the asphalt binder and aggregates. Rutting, which causes depressions in hot-mix asphalt (HMA) pavements along wheel paths, is a common type of distress. Both the loading and recovery phases of asphalt pavement performance are significantly impacted by the asphalt binder. In contrast to the extensive study conducted during the loading phase, the recovery phase receives comparatively little attention. Percent recovery tests asphalt binder elastic behaviour and stress dependence. Asphalt binder can self-repair and improve over time. Using a dynamic shear rheometer's multiple stress creep recovery method, virgin and modified asphalt binder were compared. Different temperatures and stresses were applied to the asphalt binders, and their responses were analysed. The results of the tests showed that the retrieval proportion of asphalt binder could be significantly increased by using admixtures, nanostructured materials, and viscous fluids. This case study shows that unmodified binders do not exhibit significant sensitivity to stress or strain under reasonable stress or tension conditions, nor do they showed considerable restoration under creep conditions; as a result, MSCR testing is not required for testing unmodified binders. Because of its potential as a modified binder performance indicator, Super Pave binder specification includes it. Furthermore, the data presented above demonstrates that certain modified binders provide better percentage recovery than neat binders. The viscous fluids were the ones that performed the best out of all the samples that we examined, closely followed by the nanostructured materials and the virgin binders

Mixing carbon nanotubes with asphalt binder through a foaming process toward high-performance warm mix asphalt (WMA)

ABSTRACT This paper investigates mixing carbon nanotubes (CNTs) with asphalt binder through a foaming process to produce high-performance warm mix asphalt (WMA). Two different solvents of ethanol and a water-based surfactant are used to disperse the multi-walled CNTs. Initial morphological assessment of the two CNT solutions showed that a more homogenous dispersion of the CNTs was achieved using the water surfactant solution. The foaming performance, thermal, and rheological properties of the foamed asphalt mixed with different percentages of CNTs are further investigated. The test results showed that a very small amount of CNTs (0.06% ∼ 0.1% in weight of the binder) can effectively enhance the foaming performance for bubble stability without tangibly increasing the rheological properties of the foamed asphalt. The specific heat capacity of the foamed samples was smaller than the neat binder, whereas the glass transition temperature of the foamed samples shifted to a lower temperature as compared to that of the neat binder. The thermal conductivity of the 6% CNTs sample (0.24% wt. in asphalt binder) was improved by two-fold compared with the foamed unmodified asphalt, which indicates the potential of using CNTs in the binder for enhancement of thermal properties in asphalt pavements.

Assessment of the Effect of Nono-clay on Recycled Asphalt Mixtures Resistance to Moisture

Introducing nanotechnology to the pavement industry witnessed a great interest due to the proven benefits of nanotechnology in various scientific fields. However, the reduction in the binder's characteristics might be disadvantageous to the durability of the recycled mixture, making it more susceptible to external factors such as moisture. Therefore, using nanotechnology is expected here to treat this issue. The goal of the current paper is to report on the influence of the nano-clay montmorillonite (MMT) powder (MMT k10) on the resistance to moisture in the hot recycled mixtures or the Reclaimed Asphalt Pavement mixtures (RAP mixtures). In this work, different proportions of rejuvenated RAP were employed. These proportions are 30, 40, and 50% as a percent of the overall weight of the mix. The percentages were mixed with a nano-modified neat binder with (0, 1, 3, and 5)% nono-clay MMT as a proportion of the bitumen’s weight. Two types of mixtures are prepared and used in this paper: nano-modified RAP mixtures and unmodified RAP mixtures. On both types of mixtures, the compressive strength test, the index of retained strength (IRS), the indirect tensile strength tests (ITS), and the tensile strength ratio (TSR) were carried out to compare and evaluate the moisture resistance of rejuvenated RAP mixtures. The experimental test results indicated that using 5 percent nono-clay in regenerated RAP mixes provides better performance than not using it. where it increased moisture damage resistance by5.53% for IRS value and 3.66% for TSR for 50 percent RAP mixes.

Rheological properties of asphalt binder modified with waste polyethylene: An interlaboratory research from the RILEM TC WMR

Significant volumes of waste materials such as plastics is generated every year worldwide with a potentially harmful impact on the environment. At the same time, the demand for asphalt modifiers has seen an increase over the year with consequent higher costs for these types of additives. Therefore, combining large amounts of available waste plastics with asphalt binder as an extender or modifier would potentially improve the paving material properties while limiting the disposed waste. While several rheological studies have been performed in the past, they were restricted to single research efforts hindering a consistent comparison among the valuable results of these investigations. For this reason, the Task Group 1 of the RILEM Technical Committee 279-WMR established a research activity with 11 international institutions to conduct interlaboratory research to evaluate the possibility of using waste polyethylene (PE) as an additive in asphalt binder. The study addressed the combined impact of PE materials and experimental conditions on the rheological properties of asphalt binder. For this purpose, conventional tests (penetration value, softening point temperature, and Fraass breaking point temperature) and the linear viscoelastic characterization using the Dynamic Shear Rheometer (DSR) were adopted. An unaged pen grade 70/100 neat binder was selected as the reference binder; PE-pellets and PE-shreds, produced from the recycled waste polyethylene materials, were used as the polymer additives. A single content (5%) of PE-pellets and PE-shreds was used to blend the PE material with the reference binder (95%) and prepare the two PE modified binders. Results indicate that the use of plastic modifiers leads to an overall higher complex shear modulus and softening point temperature while decreasing the penetration value. Higher dispersion in the results, especially in phase angles, was observed for blended binders at high temperatures. The PE modified binders exhibited poor reproducibility among laboratories and a low level of repeatability. Such a scatter in the data could result from an uneven dispersion of plastic material at high temperatures. In contrast, plastic shapes and batches appeared to have a limited impact. Three different rheological behaviors, neat binder, modified binder, and complex modified binder, were visually identified among the interlaboratory results and based on a simple statistical analysis of variance. Further analysis of the data suggested that the Glover Rowe (G-R) parameter can be used as a sensitive tool to classify the rheological behaviors of PE modified binders. Further experimental evaluation on specific testing conditions, such as measurement gaps of DSR at high temperatures, is recommended to advance the understanding of their influence on the rheological behavior of PE modified binders.

A Brief Overview of Utilizing Crumb Rubber as Asphalt Binder Modifier

The discarding of scrap tires is a serious environmental hazard worldwide. Simultaneously, the asphalt mixture containing neat binders do not always perform as required. Therefore, various efforts have been taken in the past to enhance the performance properties of the neat asphalt cements by modifying them with crumb rubber powder. Consequently, this will decrease the environmental hazards of waste tires. According to prior and ongoing research, the modification of asphalt mixtures using crumb rubber have enhanced the asphalt mixtures properties such as low and high temperature performance as well as rutting deformation resistance, fatigue cracking resistance. This paper affords via an overview of the physical and rheological properties of the rubberized asphalt binders under different conditions. This review transacts through the impact of crumb rubber particles on the asphalt binder’s workability, rotational viscosity, the needle penetration, softening point, low- temperature and high-temperature performance. Furthermore, fatigue cracking resistance, rutting behavior and storage stability are in the focus.

Effect of Organic-Montmorillonite on rheological performance of Bio-Asphalt composites with various oxidative aging

Several previous studies have demonstrated that bio-asphalt derived from Waste Cooking Oil (WCO) displays superior performance in cracking resistance at low and medium temperature, but inferior in high temperature rutting resistance. This study aims to further improve the rutting resistance of WCO based bio-asphalt by a compound modification with Organized Montmorillonite (OMMT). One neat asphalt binder with penetration grade of 90 is selected in this study. The WCO based bio-oils are firstly mixed with neat binders followed by further modified with the OMMT additives. The frequency sweep, linear amplitude sweep (LAS) and multiple stress creep recovery (MSCR) tests are respectively conducted for evaluation of the linear viscoelastic properties, fatigue and rutting resistance. Experimental results demonstrate again that the fatigue resistances of bio-binders are improved compared to the base asphalt whereas the addition of bio-oil obviously reduces the binder rutting resistance at high temperature. However, the OMMT addition into the bio-asphalt is found to effectively enhance the rutting resistance when increasing the OMMT content without compromising the fatigue performance. Therefore, it can be preliminary concluded that the Bio/OMMT compound modification approach can be utilized to address the rutting potential concern of WCO based bio-binders at high temperature. Furthermore, the Response Surface Methodology (RSM) is employed to model the rheological properties of Bio/OMMT compound modified binder under various modifier weights, in which the damage characteristic and performance index can be effectively estimated.

Performance of waste plastic bio-oil as a rejuvenator for asphalt binder

Pavement recycling is actively applied on asphalt roads due to ageing problems associated with bituminous binders when exposed to weathering and trafficking during their service life. Recycling of asphalt occurs through rejuvenator agents. This study utilised bio-oil produced from hydrothermal liquefaction of waste plastic films (linear low-density polyethylene - LLDPE) to rejuvenate laboratory-aged bitumen. Initially, the neat bitumen was aged through thermal ageing (Pressure Ageing Vessel – PAV) and then the aged binder was mixed with bio-oil from waste plastics at 5% and 8% bio-oil (BO) by weight of aged binder. All four binders including neat bitumen, aged bitumen, aged bitumen/BO-5% and aged bitumen/BO-8% were analysed for thermogravimetric analysis, Fourier Transform Infra-Red analysis, rheology in the linear viscoelastic region, multiple stress creep and recovery analysis, and linear amplitude sweep analysis. The ageing of neat binder resulted in hardening of the binder; however, the bio-oil rejuvenator softened the aged binder significantly. The thermo-chemical and rheological performance of aged binder was significantly improved after the addition of bio-oil. The outcomes suggest how bio-oil produced from hydrothermal liquefaction of waste plastics (possibly non-recyclable) may serve as potential rejuvenator for aged asphalt binders in an effort to recycle more using non-recyclable material.