Performance Of Asphalt Binder Research Articles

Fitting Quality of NMR Relaxation Data to Differentiate Asphalt Binders

Asphalt binder performance grades (PGs) are important metrics in designing pavements for effective transportation infrastructure. The PG system relies on the binder’s stiffness and is determined through energy- and time-intensive physical testing. Physical properties, like stiffness, can also be determined by spin–lattice NMR relaxometry, a non-destructive chemical method. NMR relaxometry can quantify the molecular mobility of materials by determining relaxation times from exponential decays of excited nuclear magnetization. While relaxation times have been used to determine physical properties of materials, a quantitative relation to the PG grades of asphalt binder is yet to be established. In this study, T1 NMR relaxation analyses were used to differentiate between solid asphalt binders and determine the fastest yet still-reliable method of modeling exponential decay data. Algorithms that fit exponential decay relaxation data using one, two, or three independent relaxation times were compared with a 128-coefficient discrete inverse Laplace transformation to determine the best mathematical fit for a comparative analysis. The number of data points was then reduced from 256 to 64 to 16 and finally to 8 data points on a relaxation curve to reduce the testing time and determine the minimum number of data points needed for comparison. Two batches of PG 64-22 asphalt binder, along with samples of PG 76-22 and 94-10 binders, were investigated. The best compromise between measuring time and data reliability was found by acquiring 64 data points and then using a biexponential model to fit the experimental data. The PG 64-22 sources provided similar results, indicating similar physical properties. The PG 64-22 and PG 76-22 binders could also be compared via monoexponential data fits, but the PG 94-10 samples required an additional relaxation parameter for comparison. To differentiate all three binder grades, the primary relaxation times, along with their relative ratios, were utilized.

Exploring the physicochemical and rheological properties of sustainable asphalt binders modified with lignin and high-viscosity additive

The primary objective of this investigation is to evaluate how the incorporation of lignin and high-viscosity modifiers impacts the performance of asphalt binders. Lignin-modified asphalt binder (LBA) and lignin-high viscosity modifier composite-modified asphalt binder (LHA) were created by blending 5 % and 15 % lignin, respectively. To understand the physicochemical interactions, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were employed to analyze functional groups, thermal properties, and phase changes. Additionally, the linear rheological behavior and nonlinear rheological behavior were evaluated through frequency sweep and multiple stress creep recovery tests. The findings suggest that lignin blends physically with the asphalt binder and high-viscosity modifier without a chemical reaction. Although the onset pyrolysis temperature of lignin is significantly lower than that of asphalt binders, due to its relatively low content, the thermal decomposition of lignin-modified asphalt binders is primarily controlled by the asphalt binder itself and still exceeds the construction temperature. However, lignin incorporation increases the asphalt binder's glass transition temperature, potentially affecting low-temperature performance. Lignin significantly enhances the modulus in the high-frequency region of both unmodified and high-viscosity modified asphalt binder. However, it has a negative effect on the modulus in the low-frequency region of high-viscosity modified asphalt binder. Furthermore, nonlinear creep recovery test results demonstrate that lignin positively contributes to the deformation resistance of unmodified asphalt binder in a content-dependent manner, whereas it reduces the elastic behavior and deformation resistance of high-viscosity modified asphalt binder. In addition, low levels of lignin increase the stress sensitivity of binders, while high levels of lignin decrease it. Despite these effects, the performance of lignin and high-viscosity additive composite-modified asphalt binder remains superior to that of unmodified asphalt binder. These findings offer valuable insights into the combined use of lignin and polymers in asphalt binder modification.

Study on use of recycled waste materials on the performance of asphalt binder and mixes: A comprehensive review

All aspects of daily living frequently involve the use of plastics. Due to the lack of effective waste treatment methods, massive global environmental problems will be caused by the accumulation of waste plastics. The use of waste materials in road building is of tremendous interest since it has the potential to reduce hazards and pollution while conserving natural resources. High-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), ethyl vinyl acetate (EVA), and polyvinyl chloride are the most appropriate and relevant of waste plastics. There are other types of waste materials used in the asphalt such as reclaimed asphalt pavement (RAP), crumb rubber (CR), steel slag, glass powder etc. These all-waste materials have been briefly discussed. In this review article several concerns have been raised about the physical and chemical qualities, of asphalt pavements that have been mixed with waste materials. Using waste materials in asphalt pavements can raise several concerns regarding the physical and chemical qualities of the resulting mixtures. These concerns typically revolve around factors such as durability, performance, environmental impact, and overall sustainability. This research article provides a thorough analysis of the wet and dry procedures used to mix different types of waste plastics. Overall, including waste plastics into asphalt mix improved rutting, fatigue, and moisture resistance. Additionally, recycling waste plastics in this manner helps in reducing environmental pollution and conserving natural resources. Overall, the inclusion of waste plastics in asphalt mixtures can contribute to the development of more sustainable and durable pavements with improved performance in terms of rutting, fatigue, and moisture resistance. There are still certain issues like compatibility and low temperature performances that need to be addressed. To overcome the aforementioned issues, many strategies are used, including the use of nanomaterials, chemical additives, and polymer additives. Additional research should be conducted to investigate the ageing effect, pavement performance monitoring, polymer stability, and the economic and environmental considerations associated with the usage of plastics in asphalt pavements.

Proposal for a New Method for Evaluating Polymer-Modified Bitumen Fatigue and Self-Restoration Performances Considering the Whole Damage Characteristic Curve

Fatigue performance and self-repairing activity of asphalt binders are two properties that highly influence the fatigue cracking response of asphalt pavement. There are still numerous gaps in knowledge to fill linked with these two characteristics. For instance, current parameters fail to accommodate these two bitumen phenomena fully. This study aims to propose a new procedure to address this issue utilizing the linear amplitude sweep (LAS) test, LAS with rest period (RP) (LASH) test, and simplified viscoelastic continuum damage (S-VECD) model. This research work used four different types of asphalt binders: neat asphalt (NA), self-healing thermoplastic polyurethane (STPU)-modified bitumen (STPB), self-healing poly (dimethyl siloxane) crosslinked with urea bond (IPA1w)-modified bitumen (IPAB), and styrene–butadiene–styrene (SBS)-modified bitumen (SBSB). Before the testing process, all the materials were subjected to short-term and long-term aging. The new procedure showed a superior capacity to analyze and accommodate all bitumen fatigue performances and self-repairing activities compared to the current method. Another finding proved that asphalt binders with a higher self-restoration behavior failed to show a better fatigue performance. Moreover, the higher fatigue performance increments produced by STPU and IPA1w in NA concerning the control bitumen were 123.7% and 143.7%, respectively. Those values were obtained with 1.0% STPU and 0.5% IPA1w in NA. A breakthrough finding demonstrated that asphalt binder fatigue response is augmented when the RP was applied at a higher damage intensity (S) value. STPB and IPAB reached their highest increments of fatigue response, containing 1.0% of STPU and 0.5% of IPA1w, respectively. Those augmentations were 207.54% and 232.64%, respectively.

Sustainability of Asphalt Mixtures Containing 50% RAP and Recycling Agents

The substitution of virgin asphalt binder with reclaimed asphalt pavement (RAP) has environmental and economic merits, however, cracking susceptibility arises due to the aged asphalt binder within RAP. The objectives of this study are to (1) enhance the cracking resistance of asphalt mixtures containing 50% RAP utilizing recycling agents (RAs) derived from six petroleum-based and bio-based materials, (2) conduct an environmental impact assessment (represented by global warming potential “GWP”) for high-RAP mixtures including RAs, and (3) estimate the cost effectiveness of including high-RAP content in asphalt mixtures. Based on the RAP asphalt binder performance grade (PG), base asphalt binder PG, and RAP content, the RA contents were determined to achieve a target asphalt binder of PG 76-22. A control mixture was benchmarked for comparison, specified for high-traffic volume roads, and contained PG 76-22 polymer-modified asphalt binder. The engineering performance of studied asphalt mixtures was evaluated using the Hamburg wheel-tracking (HWT), semi-circular bend, Illinois flexibility index, Ideal cracking tolerance, and thermal stress-restrained specimen tensile strength tests. It was found that petroleum-derived aromatic oil, soy-based oil, and tall oil fatty acid-based RAs demonstrated a successful restoration of aged RAP asphalt binder without compromising the permanent deformation resistance. The 50% RAP mixtures emitted less GWP by 41% and 42.9% using petroleum- and bio-oil RAs, respectively, and achieved a 31% cost reduction compared to the control mixtures.

The influence of Multi-Layer Plastic Packaging (MPP) on the high-temperature performance of asphalt binders and mixtures using wet and dry mixing methods

ABSTRACT High temperatures, combined with heavy traffic loads, increase the risk of permanent deformation and reduce the useful lifespan of pavements, leading to a greater need for maintenance and rehabilitation activities throughout the pavement's service life. This study aims to evaluate the effectiveness of recycled thermoplastic additives, specifically Multi-Layer Plastic Packaging (MPP) materials, in enhancing the high-temperature performance of asphalt mixtures. MPP materials, including types such as Polyester, Polyethylene, Nylon, and Metalized Polyester, were used for binder modification in asphalt mixtures. The modification was conducted using both wet and dry methods. The physical and rheological properties of the modified binders were assessed at high temperatures to determine their impact on stiffness and resistance to permanent deformation. The results indicate that MPP materials significantly improve the high-temperature performance of asphalt mixtures by enhancing binder stiffness and resistance to permanent deformation, with the wet method proving more effective than the dry method. These findings highlight the need for developing practical guidelines for incorporating MPP materials in asphalt production in the future and underscore the importance of comprehensive studies on maintenance, rehabilitation, and overall pavement lifecycle costs.

Effects of Laboratory Ageing on the Chemical Composition and High-Temperature Performance of Warm Mix Asphalt Binders

Warm asphalt mixtures can suffer from decreased short-term high-temperature performance; therefore, introducing additional modifiers can mitigate this risk. This study investigates the effects of a liquid organosilane warm mix additive (WMAd) and grade-bumping polyethylene-based additive added simultaneously to asphalt binders on their chemical composition and its relationship with performance characteristics. Previous studies found relationships between the formation of certain chemical species during bitumen ageing and the increase in their viscosity, stiffness and other performance characteristics—the present work intended to verify these relationships when the two mentioned additives are used. Two asphalt binders were investigated—a paving-grade 50/70 binder and a 45/80-55 polymer-modified bitumen. The chemical analysis was performed using Fourier-transform infrared (FTIR) spectroscopy in attenuated total reflectance mode and focused on the quantification of carbonyl, sulfoxide, polybutadiene and polystyrene structures in the asphalt binders subjected to laboratory short- and long-term ageing. Additionally, the relationships between asphalt binder performance and selected FTIR indices were evaluated using a dynamic shear rheometer. It was found that the investigated additives significantly affected the apparent contents of all evaluated chemical structures in the asphalt binders; however, these changes were not reflected in their performance evaluation.

Optimizing modified asphalt binder performance at high and intermediate temperatures using experimental and machine learning approaches

Asphalt pavements are highly susceptible to temperature-induced stresses, which can lead to significant deterioration such as rutting at high temperatures and cracking at low temperatures. These challenges are exacerbated by global warming, which raises pavement temperatures and potentially accelerates material degradation. Addressing these issues, this study utilizes two base asphalt binders, PG 64–22 and PG 76–22, and the use of phase change materials (PCMs) like styrene-butadiene-styrene, lignin, and ground tire rubber to enhance the resilience of asphalt binders. Through an extensive experimental investigation, which includes aging processes such as rolling thin film oven and pressure aging vessel, alongside a series of both traditional and advanced tests (including dynamic shear rheometer, rotational viscometer, Fourier transform infrared spectroscopy, among others), a comprehensive set of 51 samples were analysed. By incorporating these binders and PCMs into asphalt, the experimental work demonstrated a significant improvement in the thermal and mechanical properties, effectively increasing resistance to high-temperature rutting and fatigue cracking. Complementing the experimental approach, machine learning models were employed to predict complex asphalt binder properties, such as combustion value and failure temperature, based on the experimental data. This dual approach fills a significant gap in the literature by offering a more efficient method and prediction model for optimizing pavement materials amidst climate change, while also promising to significantly advance pavement technology by enhancing material design and performance.

Epoxy asphalt binder reinforced with waste polyethylene terephthalate (PET) for improving toughness

ABSTRACT The instinct brittleness of epoxy resin is one of the challenges to the durability of epoxy asphalt pavements, which may cause various failures, such as cracking, potholes and delamination. To improve the toughness of epoxy asphalts, polymer tougheners have been commonly introduced. On the other hand, the rapid accumulation of unrecycled end-of-life polyethylene terephthalate (PET) waste brings a serious environmental problem. Addressing this, the research aims to explore the use of recycled PET (rPET) as a value-added toughener for epoxy asphalt binders. To obtain this goal, waste PET bottles were cut into flakes and integrated into asphalt binders to prepare rPET modified epoxy asphalt binders. The effect of the rPET content on the phase-separated morphology, rotational viscosity and mechanical and thermal properties of epoxy asphalt binder was studied. Notably, rPET dissolved in the asphalt binder, preventing the occurrence of phase separation in the discontinuous phase of rPET modified epoxy asphalt binders. The addition of rPET increased the viscosity, dynamic modulus and the glass transition temperature (Tg) of epoxy of epoxy asphalt binder. Furthermore, the mechanical properties and low-temperature performance of epoxy asphalt binder were also augmented. Remarkably, with the addition of 3 wt% rPET, the toughness of epoxy asphalt binder increased by 48%.

An efficient and robust method for evaluating the low-temperature performance of asphalt binder based on DSR testing

The BBR test has received growing concerns regarding its applicability to field studies and special materials due to the large amount of long-term aged asphalt binder used in preparing asphalt binder beams and the time-consuming beam preparation and testing process. In recent years, the application of a dynamic shear rheometer (DSR) to investigate the low-temperature performance of asphalt binder has attracted widespread attention because it uses significantly less asphalt binder for testing and allows for easy specimen preparation. The objective of this study was to develop an efficient and robust method to evaluate the low-temperature performance of asphalt binder based on DSR testing. Frequency sweep tests were performed on twelve asphalt binders at temperatures ranging from 0 to 25 °C using the 8-mm parallel plate geometry. Two conversions were applied to frequency sweep test data in order to predict the flexural creep stiffness and m-value of asphalt binder, namely the conversion from frequency domain to time domain and the conversion from shear loading to bending loading. The 1S2P1D model was employed to construct the master curves of storage modulus and loss modulus. Afterwards, the flexural creep stiffness was predicted using the shear creep compliance master curve model, which was derived from the 1S2P1D model using the inverse Laplace transform, and the Poisson’s ratio, which was assumed to be constant. It was found that the predicted values of S(60) and m(60) were comparable to the counterparts measured by the BBR, which well demonstrated the feasibility of the proposed DSR-BBR conversion method. In comparison to existing analysis methods, the proposed conversion method strictly complied with the linear viscoelastic theory, and it enabled efficient and robust predictions because the prediction model of flexural creep stiffness had the same parameters as those of the 1S2P1D model, thus avoiding multiple data fittings.

Performance enhancement of asphalt mixture through the addition of recycled polymer materials

Enhancing the performance of asphalt binders is essential for ensuring the long-term durability and serviceability of asphalt mixtures, as it can help reduce the frequency of maintenance and repair work, ultimately leading to the development of more sustainable transportation infrastructure. To achieve this goal, this study investigates the effects of incorporating recycled polymer materials, including reclaimed polyvinyl chloride (PVC) and polystyrene (PS) derived from household waste, into hot mix asphalt. The experimental work involved subjecting the polymer-modified asphalt binders to a range of physical tests, such as softening point, penetration, ductility, indirect tensile strength, Marshall stability, and moisture susceptibility, and the results showed that the addition of recycled polymers, with an optimal content of 4%, led to lower penetration values and higher softening point temperatures, indicating improved resistance to temperature changes. Further analysis of the asphalt mixture performance revealed several beneficial outcomes, including a decrease in flow, a boost in the asphalt mixture's resistance to moisture-induced damage, and an improvement in Marshall stability and indirect tensile strength, with the inclusion of 4% recycled polymers yielding increases in Marshall stability of 43.7% and 37.4% for PVC and PS-modified mixes, respectively, and increments in indirect tensile strength of 32.2% and 29.7% for the same mixes. The study concludes that the use of recycled polymers can effectively enhance the performance and durability of asphalt mixtures, contributing to the development of more sustainable asphalt pavement construction practices by utilizing locally available or reused materials, which could lead to the increased knowledge and application of stronger and more weather-resistant asphalt mixes, ultimately promoting the advancement of sustainable transportation infrastructure.

Moisture Sensitivity Performance of Hot Mix Asphalt Mixture Incorporating Fly Ash Geopolymer (FAG) Asphalt Binder

In Malaysia, Hot Mix Asphalt (HMA) is widely used in asphalt production. HMA is a mixture of asphalt and aggregates that give durability to the road surface for pavement. Due to vehicles excessive traffic loadings that cause road surface damage, this pavement technology frequently undergoes maintenance and rehabilitation work. This study used recycled material as a modified binder and showned the best result in increasing stiffness and better rutting performance with high percentages of additives. This research focuses on the effect of FAG additive on asphalt mixture performance evaluation according to SuperpaveTM mixes design method. The procedures were specified according to the American Association of State Highway and Transportation Officials (AASHTO), American Society for Testing and Materials (ASTM), British Standard (BS) and Malaysian Standard (MS). The granite aggregate type was produced by a local quarry with conventional asphalt binder grade 80/100 and 60/70. Incorporation FAG in modified asphalt binder as levels of 0, 3, 5, 7, 9, and 11% by mass of asphalt binder. The performance of moisture sensitivity showed low moisture damage susceptibility for the mixture based on consistent values of TSR, in which all the specimens met the minimum TSR threshold of 80%. The optimization findings indicated that 9% of fly ash geopolymer might be the ideal content for modifying the asphalt binder. Overall, research findings suggest that using geopolymers may have improved some of the characteristics of asphalt binder and the performance of asphalt binders in pavement applications. Thus, the outcomes of this research were significantly used for further performance test and analysis on the asphalt mixture.

Unveiling the composite rejuvenator efficacy on performance improvement of asphalt binder including high RAP contents

Since the incompatibility between crumb rubber (CR) and reclaimed asphalt binder (RAB) can cause sedimentation and limit its application, this study employed waste cooking oil (WCO) to pre-treat CR particles at different CR/WCO ratios, and assessed its impact on performance of asphalt binders including 30 % and 50 % RABs. Anti-aging and rejuvenation potentials of corresponding composite rejuvenators in binder blends were explored by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) tests, while the performance of corresponding binder blends was evaluated by bending beam rheometer (BBR), linear amplitude sweep (LAS), and multiple stress creep recovery (MSCR) tests. Furthermore, correlation analyses were performed to explore the relationships between the chemical and rheological parameters with a significance level below 0.05. The results confirmed the rejuvenation efficacy of composite rejuvenators in high RAB, and improvement in the critical low temperature of binder blends to a higher performance grade (PG) level compared to the non-treated CR modified binder. In addition, the fatigue cracking resistance was improved at the strain levels higher than 4 % in LAS test. However, the pre-swelled CR fairly compromised the rutting performance of binder blends compared to non-treated CR, its performance was still better than virgin binder. The correlation analysis suggested that it is possible to use chemical parameters as indicators for evaluating certain rheological properties.

Application of the polyurethane foam recycling product as an asphalt extender for sustainable road construction

Polyurethane foam (PUF) is widely used across industries owing to its excellent properties, but it has caused a solid waste stream in the environment. Alcoholysis has been found to be an effective and eco-friendly approach to address this issue. However, substantial by-products are generated in the alcoholysis process, presenting challenges to waste PUF recycling. The by-products of the PUF recycling process (BPF) exhibit similar physical properties to asphalt binder. Therefore, this study uses BPF as an asphalt extender to prepare BPF-asphalt, focusing on its influence on asphalt binder properties. The results show that BPF can greatly maintain or even improve the performance of asphalt binder with good compatibility and workability through physical mixing. The optimum amount is 10 % of the mass of the base asphalt binder. Differences in chemical composition lead to differences in BPF-asphalt properties. Thermal polymerization of polystyrene with small molecular weight in BPF plays an important role in improving the high-temperature performance and fatigue resistance. The presence of diethylene glycol has a negative effect on the performance of BPF-asphalt. This study demonstrates the feasibility of the solution of BPF as an asphalt extender to alleviate the disposal pressure of waste PUF and the consumption of asphalt resources.

State-of-the-Art Review on the Behavior of Bio-Asphalt Binders and Mixtures.

Asphalt binder is the most common material used in road construction. However, the need for more durable and safer pavements requires a better understanding of asphalt's aging mechanisms and how its characteristics can be improved. The current challenge for the road industry is to use renewable materials (i.e., biomaterials not subjected to depletion) as a partial replacement for petroleum-based asphalt, which leads to reducing the carbon footprint. The most promising is to utilize biomaterials following the principles of sustainability in the modification of the asphalt binder. However, to understand whether the application of renewable materials represents a reliable and viable solution or just a research idea, this review covers various techniques for extracting bio-oil and preparing bio-modified asphalt binders, technical aspects including physical properties of different bio-oils, the impact of bio-oil addition on asphalt binder performance, and the compatibility of bio-oils with conventional binders. Key findings indicate that bio-oil can enhance modified asphalt binders' low-temperature performance and aging resistance. However, the effect on high-temperature performance varies based on the bio-oil source and preparation method. The paper concludes that while bio-oils show promise as renewable modifiers for asphalt binders, further research is needed to optimize their use and fully understand their long-term performance implications.

Investigating the properties of a novel organic composite warm mix additive on SBS modified asphalt binder

This study investigated the effects of new organic composite warm mix additive on the performance and microstructure of SBS modified asphalt binder. Acmp, as an organic composite warm mix additive, was used to prepare warm mix SBS modified asphalt binders with different contents, and compared and analyzed with Sasobit and Evotherm warm mix additives. The rheological properties of asphalt binders were evaluated by rotational viscometer, dynamic shear rheometer and bending beam rheometer. The effects of the warm mix additives on chemical composition and microstructure of binders were analyzed by fourier transform infrared spectroscopy, thermogravimetric analysis and fluorescence microscope. The results showed that, Acmp had significant viscosity reducing effect, and 6 % Acmp reduced the rotational viscosity of binder by approximately 50 %. Acmp warm mix modified asphalt binder exhibited better low temperature performance compared to Sasobit and Evotherm, but Acmp had negative impact on the high temperature performance. Acmp was mainly composed of light components produced by the cracking of rubber powder and plastic powder, which were mainly short chain alkanes and did not affect the distribution of SBS in binder. These light components were well soluble in asphalt binder to improve its fluidity and were the main components that affected the performance of binders and achieved warm mix effects. Considering the performance of asphalt binder and mixture, Acmp is more suitable for pavements in cold regions, with a recommended dosage of 5 % of asphalt mass. The findings validate the effectiveness of organic composite warm mix additives and contribute to the exploration of more efficient new warm mix technologies.

Development of superpave asphalt binder specifications to meet climate conditions in the UAE

ABSTRACT Asphalt binder's performance is highly sensitive to temperature fluctuations and climatic conditions. The selection of an inappropriate asphalt binder leads to considerable damage and impacts roads' longevity. The current selection practice of asphalt binder in the United Arab Emirates (UAE) is mainly according to the penetration grading system, which does not consider local temperature conditions. The Superpave Performance Grade (PG) system considers extreme pavement temperatures to define appropriate asphalt binder PG. This study aimed at developing the Superpave asphalt binder PG map for the UAE. The Strategic Highway Research Program (SHRP) and Long-Term Pavement Performance Program (LTPP) Superpave models were used to calculate the pavement temperatures employing air temperature records collected from 20 weather stations across the UAE. The result of the Superpave PG map highlights three distinct asphalt binder grades at 98% reliability: PG 76-10, PG 70-10, and PG 64-10. The PG 76 -10 asphalt binder is the most prevalent PG, covering more than 85% of the UAE map. However, the current construction practice utilizes penetration grades 40/50 and 60/70, through both asphalt binders are equivalent to PG 64-xx. This necessitates the use of different modifier technologies to achieve the Superpave requirements of PG 76-10 and PG 70-10.

Innovative use of nanomaterials for improving performance of asphalt binder and asphaltic concrete: a state-of-the-art review

ABSTRACT Rising costs of constructing and maintaining asphaltic concrete pavements present a challenge requiring an alternative solution. Nanomaterials can be cost-effectively integrated with asphalt binder to provide beneficial effects for asphaltic concrete mixture. This paper investigated seven different types of nanomaterials, namely nanoclay, carbon nanotube, nanosilica, nano-titanium dioxide, nano-zinc oxide, graphene oxide, and carbon nanofiber by examining their production methods, benefits, applications, and limitations based on the data available in published literature. Challenges and limitations discussed include economic, production, and blending problems, some of which are due to the lack of research on the topic. This study provides a framework from which the pavement engineering community can conduct experimental research on nanomaterials for applications in asphaltic concrete pavements. The review of previous studies reveals that new asphalt binders and asphaltic concrete mixtures incorporating nanomaterials can be developed for improved performance of flexible pavements. It is expected that further research can be devoted to overcoming the current challenges faced by aging transportation infrastructure through use of nanomaterials in asphalt binder and asphaltic concrete. Above all, research gaps in the present state of knowledge have been identified and certain recommendations are given for future investigations.

Multiscale evaluation of aging susceptibility of asphalt binders modified with recycled rubber and plastic pyrolytic oil composites

Changes in rheological performance, migration of chemical components, and microstructure transformation are some of the processes that occur as asphalt binders age across various stages throughout their lifecycle. Aging-related changes influence pavement performance, typically increasing its susceptibility to issues like fatigue and thermal cracking. Thus, comprehending the role of aging in the performance of asphalt binders is vital for devising effective pavement design and maintenance strategies. The use of plastic pyrolysis oil and recycled non-tire automobile rubber to create oil-rubber modified asphalt binders is becoming quite popular as a sustainable and environmentally friendly method for asphalt pavements. This study aimed to assess the aging behavior of asphalt binders modified with plastic pyrolysis oil and recycled non-tire automotive rubber, both separately and in composite modification. Binders underwent testing under four aging conditions: unaged, short-term aged, long-term aged, and extended long-term aged. The study focused on a multiscale assessment of aging characteristics, encompassing macroscale, mesoscale, microscale, and nanoscale analyses. At the macroscale, the binders were tested for rheological parameters using multiple stress creep recovery (MSCR), linear amplitude sweep (LAS), and Glover-Rowe (G-R) parameter tests, while the mesoscale analysis was conducted using Fourier-transform infrared (FTIR) spectroscopy. Additionally, microstructural analysis was performed using atomic force microscopy (AFM), and nanoscale evaluation was carried out using nuclear magnetic resonance (NMR). Finally, a comprehensive assessment index that included all the parameters under study was generated using radar graph analysis. It was observed that modifying an asphalt binder with a heat-preheated composite of plastic pyrolysis oil and recycled non-tire automotive rubber showed the lowest CAI values, thus helping to mitigate the effects of aging and achieving enhanced binder performance.

Morphological, thermochemical, and rheomechanical evaluation of self-healing performance of asphalt binder modified with hybrid-structured phase change material capsules

Currently, sustainable pavement research focuses on modified asphalt binders with self-healing features for achieving durability and safety goals. This study assesses the self-healing behavior of asphalt binders incorporating innovative lab-manufactured hybrid-structured phase change material capsules (HPCMC). The HPCMC, using by-product paraffin oil as a core encapsulated by waste nano-silica fume as a shell, varied in core-to-shell ratios (0.5:1, 1:1, 2:1) and dosages (1 %, 3 %, 5 %, 7 %) by asphalt weight. Morphological, thermal, and chemical characterizations were conducted using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). Healing efficiency of unaged and short-term aged HPCMC-modified binders was evaluated using SEM and energy dispersive X-ray (EDX) for morphological and chemical analysis. Rheomechanics were examined through rotational viscosity (RV), performance grading (PG), multiple stress creep recovery (MSCR), strain sweep (SS), frequency sweep (FS), linear amplitude sweep (LAS), and linear amplitude sweep-based healing (LASH). Study findings exhibit superior healing in HPCMC-modified binders compared to unmodified ones, particularly at a 3 % dosage and 1:1 core-to-shell ratio in unaged conditions. This study also evaluates healing assessment criteria and validates the self-healing mechanism, indicating significant potential for the proposed approach to revolutionize pavement construction and maintenance.