High-temperature Storage Stability Research Articles

Evaluation of the Effect of C9 Petroleum Resin on Rheological Behavior, Microstructure, and Chemical Properties of Styrene–Butadiene–Styrene Modified Asphalt

Understanding the modification mechanism of C9 petroleum resin (C9PR) on styrene–butadiene–styrene (SBS) polymer modified asphalt properties is of significant importance. In this paper, dynamic shear rheometer (DSR), storage stability, fluorescence morphology (FM), scanning electron microscope (SEM), Fourier transform-infrared (FTIR) spectrometer, and molecular dynamic (MD) simulation were adopted to evaluate the rheological, chemical, and microstructure molecular motion state of C9PR and SBS composite modified asphalt at different aging states. The DSR storage results indicate that the addition of C9PR could improve the high-temperature property, storage stability, and temperature susceptibility. FM and SEM results indicate that the network microstructure was enhanced and the roughness between polymer resins and virgin asphalt was improved at the microscopic scale. The MD results indicate that the heterogeneity between C9PR and SBS modified asphalt was demonstrated, and the bonding energies were enhanced with the addition of C9PR. Moreover, the FTIR results indicate that new function groups were generated in addition to C9PR. In general, the addition of C9PR is a good approach to promote high-quality polymer modified asphalt (PMA) for pavement engineering.

Nano-Additives in Asphalt Binder: Bridging the Gap between Traditional Materials and Modern Requirements

This research delves into the realm of asphalt technology, exploring the potential of nano-additives to enhance traditional asphalt binder properties. Focusing on Nano-Titanium Dioxide (NT), Nano-Aluminum Oxide (NA), and Nano-Silica Oxide (NS), this study investigates the effects of incorporating these nanomaterials at varying dosages, ranging from 0% to 8%, on the asphalt binder’s performance. This study employs a series of experimental tests, including consistency, storage stability, rotational viscosity, mass loss due to aging, and rheological properties, to assess the impact of nano-additives on asphalt binder characteristics. The findings indicate a substantial improvement in the consistency of the asphalt binder with the addition of nanomaterials, particularly NS, which shows a 41% reduction in penetration at an 8% content and a notable increase in the softening point. The storage stability tests reveal that NS-modified asphalt exhibits superior stability compared to NT and NA, with a significantly lower ΔT increase. Furthermore, the investigation into rotational viscosity suggests that NS, despite increasing the binder’s viscosity, does not exceed the AASHTO M320 threshold, ensuring the binder’s workability. Aging tests demonstrate that NT, at lower concentrations, acts as an effective anti-aging agent, whereas NA and NS tend to increase the mass loss, impacting thermal stability. This study concludes that while each nanomaterial uniquely influences the asphalt binder’s properties, NS stands out in terms of enhancing the high-temperature performance and storage stability. Optimal dosages of 6% for NT and NA and 4% for NS are recommended based on the Overall Desirability analysis. This research bridges the gap between traditional asphalt materials and modern requirements, highlighting the transformative impact of nano-additives in advancing asphalt pavement technology.

Evaluation of asphalt binder and mixture properties utilizing fish scale powder as a biomodifier

Fish represents an abundant and underutilized waste product from the fishing industry. This study investigated the effects of incorporating fish scale powder (FSP) at various dosages (3%, 6%, 9%, and 12%) on the properties of asphalt binder and mixtures. Conventional tests, viscosity, storage stability, Fourier transform infrared spectroscopy, and multiple stress creep recovery tests were conducted on the binder. Mix design, wheel tracking, indirect tensile strength, fatigue, and ultrasonic pulse velocity tests were evaluated for the asphalt mixtures. The results showed that FSP increased the binder’s stiffness and reduced the temperature susceptibility but compromised the low-temperature performance and workability regardless of the dosages. The storage stability test results demonstrated the improved high-temperature storage stability. In the mixtures, the permanent deformation resistance enhanced with increasing the FSP content, decreasing the rut depth from 4.3 mm for the control sample to 2.9 mm at 12% FSP. The moisture damage resistance, indicated by the tensile strength ratio, increased from 90% for the control sample to 94.1% at 12% FSP. However, the fatigue life decreased from 14010 cycles for the control sample to 11190 cycles at 12% FSP. The dynamic and elastic modulus values before conditioning increased with higher FSP dosages, and this increasing trend was also observed after conditioning, signifying greater stiffness retention and moisture resistance of the asphalt mixtures containing higher amounts of FSP. Numerically, the 6–9% FSP range offered the optimum balance, improving the rutting resistance by 18% and the moisture resistance by 3.2% compared to those of the control sample, while limiting the fatigue life to 12% and maintaining the workability. Overall, FSP has potential for use as an asphalt biomodifier by transforming an environmental liability into a value-added sustainable paving material.

Evaluation of the Thermal Stability and Micro-Modification Mechanism of SBR/PP-Modified Asphalt.

To evaluate the thermal stability of composite polymer-modified asphalt, thermoplastic elastomer styrene-butadiene rubber (SBR)/polypropylene (PP) pellets were prepared using a hot-melt blending technique, with butyl rubber powder and waste polypropylene pellets as raw materials. The effects of different evaluation indexes on the thermal stability of SBR/PP-modified asphalt were investigated using a frequency scan test and a multi-stress creep recovery (MSCR) test, and the compatibility of SBR/PP particles with asphalt was studied using the Cole-Cole diagram and microstructure images. The tests show that, firstly, the performance grade (PG) classification of asphalt can be improved by adding an SBR/PP thermoplastic elastomer to enhance the adaptability of asphalt in high- and low-temperature environments, and the evaluation separation index can reflect the high-temperature storage stability of composite-modified asphalt more reasonably. Additionally, the larger the rubber-to-plastic ratio the worse the high-temperature thermal stability of composite-modified asphalt. Moreover, the addition of additives to the composite particles can promote the SBR/PP particles in the asphalt to be more uniformly dispersed, forming a more desirable microstructure and improving the thermal stability of composite-modified asphalt. Ultimately, the semicircular curve of the Cole-Cole diagram can reflect the compatibility characteristics of the two-phase structure of SBR/PP-modified asphalt, which can be used as an auxiliary index to evaluate the compatibility of polymer-modified asphalt.

Controllable organic/inorganic composite film enables improved long-term and high-temperature storage performance of lithium primary battery

Though lithium primary battery has been widely used, high temperature and long-term storage still possibly cause its failure because of the active lithium anode, which continuously reacts with electrolyte, forms an unstable solid electrolyte interface and leads to the degradation of battery performance. In this work, a novel organic-inorganic composite protecting film composed of well-dispersed inorganic lithium nitride (Li3N) among poly (propylene carbonate) (PPC) organic matrix is controllably fabricated on the Li anode by spin coating, to enhance interfacial compatibility and stability. The composite film exhibits superior ionic conductivity of 3.57 × 10−4 S cm−1, and the Li-CFx battery with composite film delivers an excellent specific discharge capacity of 940 mAh g−1 at 0.1 C, and excellent rate capacity of 492 mAh g−1 even at 8 C. After storage at room temperature and 55 °C for 60 days, the battery can still release high specific capacities of 867 and 536 mAh g−1. With the assistance of composite film, a stable Li3N/LiF-rich SEI is formed on the Li anode and LiF-rich CEI is generated on the CFx cathode, ensuring long-term and high-temperature storage stability of Li-CFx battery. This study demonstrates a facile organic/inorganic composite film protecting strategy to achieve high-performance lithium battery.

Effect of styrene butadiene styrene and desulfurized rubber powder on asphalt modification: Preparation, performance enhancement, mechanism analysis

The aim of this study is to propose a desulfurized rubber powder / styrene butadiene styrene (DRP/SBS) composite modified asphalt technology by combining the advantages of DRP and SBS. This reduces the production cost of modified asphalt and improves the performance of asphalt. In this paper, orthogonal tests were used to optimize preparation process parameters of DRP/SBS composite modified asphalt. And the physicochemical properties, modification mechanism of composite modified asphalt had been thoroughly studied. Subsequently, the results showed that the optimum content of DRP and SBS modifiers are 25 % and 2 %, respectively. The suitable preparation process is to add SBS first, then DRP, while shearing at 5000 r/min for 50 min. In addition, DRP/SBS composite modified asphalt has better high-temperature performance, viscosity-temperature characteristics, aging resistance, and storage stability. Meanwhile, the storage stability of the composite modified asphalt was verified by fluorescence microscopy test. Through the Fourier transform infrared spectroscopy test, it was observed that the composite modified asphalt modification process is a compatible and stable modification of physical and chemical coexistence. Overall, the composite modification method achieves recycling of waste tires while improving pavement performance, thus promoting the sustainability of pavement.

Molecular dynamics simulation and experimental analysis on fluidity improvement of liquid rubber modified asphalt binder

Liquid styrene-butadiene rubber (LSBR) has been used as a modifier to improve high-temperature storage stability and cracking resistance of asphalt binder. However, the interaction mechanism between LSBR and asphalt binder at both micro and macro scales has not been well understood. In this study, the intermolecular dynamics, rheological and chemical properties of liquid rubber modified asphalt (LRMA) binder by laboratory experiments and molecular dynamics simulation. Five LSBR dosages (0, 0.5, 1.0, 1.5, 2.0, and 2.5% by weight of asphalt binder) were applied to prepare the LRMA binders. Frequency sweep, performance grading, and multiple stress creep recovery (MSCR) tests were conducted to assess the intermediate- and high-temperatures rheological properties of modified asphalt binders. Fourier transforms infrared (FTIR) spectroscopy was applied to evaluate the chemical properties. Molecular dynamics (MD) simulation was performed to evaluate compatibility and molecular mobility during self-healing process. The results indicated that the addition of LSBR improved the fluidity of asphalt binder at intermediate- and high- temperature, and also enhanced the susceptibility to temperature changes. FTIR results showed that LSBR could effectively delay aging of asphalt binder and ameliorate the service performance degradation. The MD simulation results indicated that the addition of LSBR could improve the solubility of different components in asphalt and the homogeneity of asphalt system. LRMA had a better capability to heal micro-crack than the unmodified asphalt binder. LSBR could improve the fluidity of base asphalt and aged asphalt. It is feasible and appropriate to use liquid styrene-butadiene rubber to improve fluidity of asphalt to meet the requirements of construction and production. Keywords: asphalt fluidity, molecular dynamics simulation, liquid styrene-butadiene rubber, self-healing, rheological property.

Effects of using waste solid sheet photopolymer plates in combination with SBS on the rheological properties of bitumen

ABSTRACT Large quantities of Solid Sheet Photopolymer plates (SSP) are used and wasted by the flexographic printing industry worldwide. The use of waste SSP, contains valuable polymers for bitumen modification, is an effective way of disposing of post-consumer products and an alternative way of obtaining new modifiers with good properties. Styrene–butadiene-styrene (SBS) copolymer, which is widely used in bitumen modification, causes excessive costs. The purpose of this study is to look at the effects of using SSP in combination with SBS and how much SSP saves on SBS content. Dynamic Shear Rheometer (DSR), Multi-Stress Creep Recovery (MSCR), Bending Beam Rheometer (BBR), Storage Stability tests, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) were carried out. The performance of the 4 and 5 wt.% single SBS modifications was compared with the SBS + SSP combination. SBS and SSP additives were found to interact well, and the use of 7% SSP in combination with 2% SBS provided improved low and high temperature performance and storage stability compared to the single 5% SBS modification. The use of waste SSP, which is cheaper than bitumen, together with SBS in bitumen modification offers a cost-effective and environmentally friendly solution without compromising performance.

High-Temperature Rheological Properties and Storage Stability of Bitumen Modified with the Char Produced from Co-Pyrolysis of Different Wastes

By enhancing the bitumen properties with the additives produced from waste, not only can the performance of flexible pavements be improved, but it can also contribute to the environment. This research aims to produce a novel pyrolytic char from different wastes and to investigate the usability of this char as an additive in bitumen. In this study, first, the pyrolytic char was produced from the co-pyrolysis of three different wastes, including waste paper cups, polypropylene (PP), and polyethylene terephthalate (PET) waste. Properties of the char were determined by using CHN (carbon, hydrogen, and nitrogen) and Fourier transform infrared spectroscopy (FTIR) analyses. The high-temperature rheological properties of binders were evaluated by using DSR (dynamic shear rheometer), RV (rotational viscometer), softening point, and penetration tests. Additionally, specific gravity, storage stability, high-temperature performance grades (PGs), and temperature susceptibilities of binders were determined. Test results showed that this pyrolytic char enhanced the high-temperature properties of neat bitumen by increasing softening point, viscosity, rutting resistance, and high-temperature PG of pure bitumen. Additionally, it can be said that the bituminous binder modified with this pyrolytic char had good storage stability when it was used at an 8% ratio in neat bitumen.

Preparation of terminal blend/ grafting activated crumb rubber composite modified asphalt based on response surface methodology

Recycling waste tires, crushing them into crumb rubber (CR) and adding them to asphalt can effectively improve the performance and prolong the service life of asphalt pavement. However, the crumb rubber modified asphalt (CRMA) prepared by aforementioned process is prone to segregation during storage and transportation. The terminal blend rubber asphalt (TB) prepared with fine rubber powder by high-speed shearing at high temperature for long time, which effectively improves the storage stability and working performance of crumb rubber modified asphalt, but reduces the high-temperature performance. In this study, grafting activated crumb rubber (GACR) was incorporated into TB to improve its high temperature performance without impairing storage stability. Using shearing temperature, shearing time and grafting activated crumb rubber content as influencing factors, the response surface method (RSM) was carried out to optimize the preparation process. The results indicated that 180°C was a critical temperature, and the swelling of crumb rubber dominated with the temperature below it, but the desulfurization prevailed with the temperature above it. The extension of time favored the swelling of crumb rubber at low temperature but promoted desulfurization at high temperature. With the increase of crumb rubber content, the high temperature performance of modified asphalt improved whereas the storage stability deteriorated. According to the determination of response values and the prediction of optimal values, the suitable preparation conditions and parameters were recommended as shearing temperature of 190°C, shearing time of 90 min, and GACR content of 15%. The composite modified asphalt prepared through the optimized process showed good high temperature stability and storage stability.

Study on Properties and Micro-Mechanism of RHB-SBS Composite-Modified Asphalt.

Rice husk biochar (RHB) is a renewable agricultural waste, and its fixation on pavements helps develop environmentally friendly, economical, and sustainable asphalt pavements. This paper used RHB to replace part of styrene-butadiene-styrene (SBS) for the composite modification study of matrix asphalt. The high- and low-temperature properties and microscopic mechanisms of the composite-modified asphalt were studied through a series of tests. The results showed that, compared with SBS-modified asphalt, the softening point, viscosity, complex shear modulus, stiffness modulus, and rutting factors of RHB-SBS composite-modified asphalt were improved. In contrast, the ductility and creep rate were slightly decreased, indicating an improvement in the high-temperature performance of composite-modified asphalt, but a slight decrease in its low-temperature performance. The process of RHB and SBS composite modification was mainly physical blending, with only a small number of chemical reactions, and no new functional groups were generated. The porous structure of RHB enables it to adhere better to the network crosslinked continuous phase system formed by SBS and matrix asphalt. This results in composite-modified asphalt with good high-temperature storage stability and rheological properties. Therefore, RHB-SBS composite-modified asphalt can be applied to high-temperature areas and rice-producing areas, and the optimal content of RHB is suggested to be 15%.

Characterization of chloroprene rubber-modified asphalt binders

Despite being one of the potential candidates for a suitable elastomeric additive to modify asphalt binders, there is a lack of research on using chloroprene rubber (CR). This study evaluates the suitability of using CR to enhance asphalt binder properties, particularly rutting and fatigue performances. Two different grades of asphalt binder (60/70 and 85/100 penetration grade) were modified by 3.5% and 7% CR to meet this end. The conventional physical, high-temperature storage stability, rotational viscosity (RV), dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), and linear amplitude sweep (LAS) tests were used to examine various features of the CR-modified asphalt binder. Results indicate that CR decreases penetration, ductility, and temperature susceptibility and increases softening point and viscosity of the asphalt binder. Additionally, the CR-modified binder can present acceptable pumpability and workability within the construction temperature range. However, the CR-modified binder has phase separation potential, particularly at high modification contents. Based on the results of MSCR and LAS tests, CR can effectively increase the rutting resistance, elastic recovery, and fatigue life of the asphalt binder. Nevertheless, the CR-modified asphalt binder’s rutting and fatigue behaviors depend mainly on the grade of the base asphalt binder.

Evaluating the High-Temperature Properties and Reaction Mechanism of Terminal Blend Rubber/Nano Silica Composite Modified Asphalt Using Activated Rubber.

Terminal blend (TB) rubberized asphalt is a popular technology in the production of rubberized asphalt. However, it always presents challenges regarding the inadequate high-temperature rutting performance of the binders. Additionally, crumb rubber (CR), a modifier of asphalt is a cross-linked material which presents poor compatibility between CR particles and bitumen. Incorporating nanomaterials and pretreating CR particles are two possible solutions to address this drawback. But the performance improvement and modification mechanism of the composite TB binders is not clearly understood. Therefore, the purpose of this research was to evaluate the high-temperature properties and reaction mechanism of the TB rubber/nano silica composite modified asphalt using microwave activated rubber. To achieve the research purpose, bitumen penetration grade 80-100 was first modified with 8% CR particles at elevated temperature to produce TB rubberized asphalt followed by the addition of 0.5, 1.5 and 3.0% weight percentage of nano silica to produce TB rubber/nano silica composite modified asphalt. Short and long-term aging tests were performed on samples by thin film oven test (TFOT) and pressure aging vessel (PAV) prior to chemical and rheological tests. The results of the study shows that nano silica has a great influence on the high temperature rutting resistance, storage stability and anti-aging properties of TB rubberized asphalt. Nano silica promoted good interaction and compatibility between CR particles and bitumen and improved the overall rheological properties of the binders. XRD test results revealed that the TB rubberized/nano silica composite modified asphalt samples were amorphous materials and did not have a crystalline structure. The reaction mechanism between rubber and asphalt was found to be physical, whereas nano silica interacted chemically with TB rubberized asphalt. In light of these findings, this research concluded that nano silica evidently improves the high-temperature rutting properties of TB rubberized asphalt, which deserves further exploration and application.

Research on rheological properties of CNT-SBR modified asphalt

For the sake of improving the high-temperature rutting resistance, storage stability, and fatigue endurance of SBR-modified asphalt. In this study, powdered carbon nanotubes (CNT) with a fineness of 1000 mesh were used to modify 4 % further SBR-modified asphalt. The physical properties and modification mechanism of CNT-SBR modified asphalt were studied by segregation test, temperature sweep, multiple stress creep test (MSCR), bending beam rheological test (BBR), linear scanning (LAS), and Fourier transform infrared spectroscopy (FTIR). Based on the test results, CNT incorporation can significantly enhance the rheological properties of SBR-modified asphalt, making it suitable for supporting higher traffic loads. Compared with SBR-modified asphalt, 1.5 %CNT-SBR modified asphalt significantly enhanced its high-temperature characteristics and anti-aging performance. −12 °C low-temperature stress relief rate raised by 12.6 %. Meanwhile, the 1.5 %CNT-SBR modified asphalt has excellent storage stability at high temperatures, the 70℃ dissociation rate is only 0.03, and fatigue life could be increased by 80.4 %. FTIR test showed that the reaction process of CNT, SBR, and neat asphalt belongs to physical blending. Moreover, FTIR test results showed that CNT and SBR could improve the anti-aging performance of neat asphalt. Careful consideration of CNT-SBR modified asphalt mechanical properties, when the SBR content is 4 %, the recommended CNT content is 1.5 % (1.5 %CNT-SBR).

Multi-Scale Characterization of High-Temperature Properties and Thermal Storage Stability Performance of Discarded-Mask-Modified Asphalt

In the context of the global pandemic of COVID-19, the use and disposal of medical masks have created a series of ethical and environmental issues. The purpose of this paper is to study and evaluate the high temperature properties and thermal storage stability of discarded-mask (DM)-modified asphalt from a multi-scale perspective using molecular dynamics (MD) simulation and experimental methods. A series of tests was conducted to evaluate the physical, rheological, thermal storage stability and microscopic properties of the samples. These tests include softening point, rotational viscosity, dynamic shear rheology (DSR), Fourier transform infrared (FT-IR) spectroscopy and molecular dynamics simulation. The results showed that the DM modifier could improve the softening point, rotational viscosity and rutting factor of the asphalt. After thermal storage, the DM-modified asphalt produced segregation. The difference in the softening point between the top and bottom of the sample increased from 2.2 °C to 17.1 °C when the DM modifier admixture was increased from 1% to 4%. FT-IR test results showed that the main component of the DM modifier was polypropylene, and the DM-modified asphalt was mainly a physical co-blending process. MD simulation results show that the DM modifier can increase the cohesive energy density (CED) and reduce the fractional free volume (FFV) of asphalt and reduce the binding energy between base asphalt and DM modifier. Multi-scale characterization reveals that DM modifiers can improve the high temperature performance and reduce the thermal storage stability of asphalt. It is noteworthy that both macroscopic tests and microscopic simulations show that 1% is an acceptable dosage level.

Properties and mechanism of SBS/crumb rubber composite high viscosity modified asphalt

Previous studies have shown that traditional modified asphalt is difficult to meet the requirements of road quality at the requirements of permeable pavement quality at complex service environments. SBS/crumb rubber composite high viscosity modified asphalt(SBS/CR) was prepared by adding tackifying resin and other modifiers. Standard tube separation tests and rheological results showed that the SBS/CR has better high-temperature performance and storage stability. Atomic force microscopy (AFM) results concluded that the modifiers formed a stable network structure in asphalt system, restricting the free movement and diffusion of asphalt molecules. Asphalt molecules undergo phase changes in a small range, resulting in a "Bee structure" with a large number, small area, and uniform distribution, which improved its surface roughness. Fourier infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analyses confirmed the modification mechanism includes both chemical reaction and physical modification. The tackifying resin was mainly combined with the asphalt binder in the form of physical fusion. Compared with matrix asphalt, the internal structure of the SBS/CR was more stable, the heat absorption area became smaller, and the thermal stability was improved.

Effect of Aromatic Petroleum Resin on Microstructure of SBS Modified Asphalt

In this paper, aromatic petroleum resin (APR) was used as raw material. The fluorescence microscopic photography of styrene-butadiene-styrene block copolymer (SBS) modified asphalt with different contents of APR was carried out, and the effect of APR on the dispersion of SBS modified asphalt was quantitatively studied. The nano-surface morphology of SBS modified asphalt with different APR contents was tested by atomic force microscope (AFM), and the effects of APR content on AFM nanoscale parameters such as roughness and maximum amplitude were analyzed. In addition, this paper also tested the basic technical indexes of SBS modified asphalt with different APR contents and revealed its improvement law on the pavement performance of SBS modified asphalt. The results show that the use of APR is beneficial to the shearing of SBS into smaller particles. The larger the amount of APR, the smaller the maximum particle size and average particle size of SBS in asphalt and the smaller the roughness and maximum amplitude of SBS modified asphalt. APR can improve the viscosity and low-temperature ductility of SBS asphalt to a certain extent. High-temperature storage stability is improved obviously; SBS modified asphalt mixed with APR has a more dense spatial cross-linking structure after thorough development. The research results are helpful to reveal the mechanism of APR improving the performance of SBS polymer asphalt.

Nano-Al2O3 composite on intermediate and high temperature properties of neat and modified asphalt binders and their effect on hot mix asphalt mixtures

Composite modification is increasingly used to alleviate the detrimental problems associated with asphalt modifiers and meet the massive demand for asphalt pavement. In this study, nano-Al2O3 composite modifications at three concentrations of 1%, 2%, and 3% by weight of asphalt binder were implemented in neat and modified asphalt binders to improve their performance at high and intermediate temperatures. These binders were evaluated in terms of their physical, rheological, and high-temperature storage stability properties. In addition, nano-Al2O3 composite modified binders were utilized in asphalt concrete and investigated for their resistance to cracking, permanent deformation, and moisture damage. The nano-Al2O3 composite modifications were made using neat, polymer-modified, and crumb-rubber (CR) modified asphalt binders. Adding nano-Al2O3 to the asphalt binders was found to improve stiffness, high-temperature storage stability, permanent deformation resistance, and cracking tolerance. Moreover, the composites of nano-Al2O3 with neat and modified asphalt binders were found to provide improved resistance to permanent deformation, cracking, and moisture damage in hot mix asphalt concrete. The composite of 2% nano-Al2O3 showed the best performance in terms of resistance to permanent deformation, the composite of 3% nano-Al2O3 showed the best performance in terms of resistance to moisture damage, the composites of 2% nano-Al2O3 with polymer and CR-modified asphalt binders both showed the best performance in terms of resistance to cracking, and the composite of 3% nano-Al2O3 with AC20 showed improved resistance to cracking.

Synergistic effect of SBS copolymers and aromatic oil on the characteristics of asphalt binders and mixtures containing reclaimed asphalt pavement

Rejuvenators have been utilized to restore the physical and rheological properties of aged asphalt binders found in the reclaimed asphalt pavement (RAP). Also, the rejuvenators are utilized to enhance the cracking resistance of asphalt containing RAP. In addition, polymers have been efficiently applied to enhance the rutting performance of rejuvenated mixtures. The purpose of this study was to assess the influence of combining SBS copolymers and aromatic oil (AO) at the same time as a hybrid rejuvenator (HR) on the performance of high RAP asphalt binders and mixtures. HR is a mixture of 25% SBS and 75% AO. The properties of the rejuvenated binders were assessed by SARA (Saturates, Asphaltene, Resin, and Aromatics) fractions analysis, Fourier Transform Infrared Spectrum (FTIR), physical tests, high-temperature storage stability test, Dynamic Shear Rheometer (DSR) test, and Bending Beam Rheological (BBR) test. In addition, the mechanical behaviour of the rejuvenated mixtures was assessed using the Indirect Tensile Strength (ITS) test, moisture susceptibility test, resilient modulus test, and wheel tracking rutting test. The results showed that appropriate adjustment of the SARA fractions and SBS copolymer could improve the overall performance of mixtures and binders with high RAP content. However, it is asserted that a field investigation of this compound rejuvenator should be done to further analyze its influence on the long-term field behavior of high RAP mixtures.

Evaluation method of storage stability of SBS modified bitumen based on dynamic rheological properties

In order to better evaluate the storage stability of Styrene-Butadiene-Styrene Block copolymer (SBS) modified bitumen at high temperature, this paper analyzed the law of Dynamic shear rheological (DSR) test results of SBS modified bitumen after high-temperature storage and proposed DSR segregation parameters and DSR segregation index of SBS modified bitumen based on DSR test. Many kinds of SBS modified bitumen were prepared, and the application of DSR segregation index to evaluate the high-temperature storage stability of SBS modified bitumen was carried out. The main conclusions are: Take the DSR test results of SBS modified bitumen stored at high temperature but continuously stirred without segregation as the reference value, under the same storage temperature and time, the percentage of the difference of Complex modulus (G*) or Phase angle (δ) or Rutting factor (G*/sin δ) between the upper 1/3 and the bottom 1/3 of SBS modified bitumen to the reference value shows a linear relationship at different scanning temperatures. The closer the slope of DSR segregation parameters with temperature is to 0, the better the storage stability of the bitumen is. DSR segregation index takes DSR segregation parameter as parameters and is associated with the difference of segregation softening point. When the DSR segregation index is greater than 0, the storage stability of SBS modified bitumen can meet the requirements of the current standard. DSR segregation index is not bound to the type of bitumen, it is speculated that it is closely related to the compatibility between bitumen and SBS modifier. All factors affecting the storage stability of SBS modified bitumen affect the DSR segregation index. DSR segregation index has high stability in the evaluation of high-temperature storage stability of SBS modified bitumen and can be used as an auxiliary evaluation index of 48 h segregation softening point difference.