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As foaming agent for the preparation of zeolite-foamed asphalt, the foaming water released from EC130 warm-mix additive and the residual zeolite minerals have different effects on the properties of asphalt. To investigate the effect of EC130 warm-mix additive on the high temperature performance and fatigue resistance of SBS modified asphalt, three additives of limestone powder, EC130 zeolite mineral and EC130 warm-mix additive were used, and the single-factor test was designed with additive dosage as variable. By temperature scan test, multiple stress creep recovery test and linear amplitude sweep test, the effects of EC130 zeolite mineral and foaming water released from EC130 warm-mix additive on the high temperature performance and fatigue resistance of SBS modified asphalt were compared and analyzed with reference to the effect of limestone powder on asphalt properties. The results show that like limestone mineral powder, the EC130 zeolite mineral in zeolite foamed asphalt can increase the elasticity and decrease the viscosity, which is favorable for rutting resistance but unfavorable for fatigue resistance. The foaming water in zeolite foamed asphalt can increase the viscosity and decrease the elasticity, which is favorable for fatigue resistance but unfavorable for rutting resistance. [ABSTRACT FROM AUTHOR]

Past studies broadly discussed the effect of sulfur on the rheological properties of styrene–butadiene–styrene (SBS) modified asphalt, while the relationships between the rheological properties and phase behaviour of SBS-modified asphalt after sulfur vulcanisation have received less attention, which limits the further understanding of the relations between the structure and performance. To this end, this paper is aimed to discuss viscoelastic response at the molecular level and reveal the enhancement mechanism of SBS-modified asphalt after adding sulfur. Thus, the morphology, phase structure, and rheological behaviour of SBS/Sulfur modified asphalt were investigated by experimental assessment and molecular dynamics. Based on the results, it was found that the polybutadiene segments in SBS copolymer are the leading reactive site of vulcanisation, the interactions between SBS copolymer and light components were enhanced by sulfur treatment, the orderliness of asphalt molecules in SBS/sulfur modified asphalt was strengthened, and SBS copolymer presents a stronger attraction to aromatic after vulcanisation, which means the increase of boundary layer is also the significant cause to the improvement of compatibility. The findings are expected to deepen understanding of the vulcanisation mechanism and the rheological behaviour of SBS/Sulfur modified asphalt. [ABSTRACT FROM AUTHOR]

The rule and mechanism of influence of asphalt storage tank on heat storage performance of SBS modified asphalt were simulated in a laboratory oven. The three indexes, viscosity index and force ductility index of SBS modified asphalt with different heat storage time were tested before and after RTFOT aging, and the relationship between each index and the heat storage time was analyzed. The causes for the change of the three indexes and the viscosity index were revealed through the force ductility test. The results showed that, with the prolongation of the heat storage time of SBS modified asphalt, the penetration, softening point and 5°C ductility of SBS modified asphalt before and after RTFOT aging decreased while the Brinell viscosity, peak force of force ductility curve, F0, turning point tension, F1, and breaking tension, F2, increased. The indexes of SBS modified asphalt after RTFOT aging deteriorated further, which was mainly caused by the change of base asphalt and SBS network nodes. The tensile compliance index, f, in the force ductility test has a good negative correlation with the heat storage time, which can be used as a key indicator to evaluate the heat storage performance of asphalt. [ABSTRACT FROM AUTHOR]

To study the regeneration effect and mechanism of waste engine oil(WEO) on styrene-butadiene-styrene(SBS) modified asphalt. The aged SBS modified asphalt was prepared by pressurized aging vessel test, the regenerated asphalt containing different content of WEO was produced, and the physical and rheological properties of regenerated asphalt were evaluated. In addition, the regeneration mechanism of aged SBS modified asphalt was studied by using infrared spectrum test, four-component analysis test, and fluorescence microanalysis test. The results show that the penetration and ductility of aged SBS modified asphalt decrease, and the softening point and viscosity increase compared with virgin SBS modified asphalt. The penetration and ductility of aged SBS modified asphalt are increased with the increase of the content of WEO and the softening point and viscosity are decreased. The high-temperature rheological properties of aged SBS modified asphalt decreased with the content of WEO increased and the fatigue life is improved. WEO can reduce the stiffness modulus of aged SBS modified asphalt, and has no significant effect on the creep rate index. The SBS is damaged, and the content of carbonyl and sulfoxide in SBS modified are increased during the aging process and the content of carbonyl and sulfoxide are decreased with the content of WEO increased, which belongs to the process of physical regeneration. The content of saturated and aromatic decreased during the aging process, while the content of colloid and asphaltene increased, however, the effect of WEO on aged SBS modified asphalt is the opposite. The broken SBS molecules will swell under the action of waste oil and restore the properties of aged asphalt. [ABSTRACT FROM AUTHOR]

Due to the superiorities of Styrene butadiene styrene (SBS) modified asphalt, it is widely used in civil engineering application. Meanwhile, accurately predicting and obtaining performance parameters of SBS modified asphalt in unison is difficult. At present, it is essential to discover an accurate and simple method between the input and output data. ANNs are used to model the performance and behavior of materials in place of conventional physical tests because of their adaptability and learning. The objective of this study discussed the application of ANNs in determining performance of SBS modified asphalt, based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) tests. A total of 150 asphalt mixtures were prepared from three matrix asphalt, two SBS modifiers and five modifier dosages. With the most suitable algorithm and number of neurons, an ANN model with seven hidden neurons was used to predict SBS content, needle penetration and softening point by using infrared spectral data of different modified asphalts as input. The results indicated that ANN-based models are valid for predicting the performance of SBS modified asphalt. The coefficient of determination (R2) of SBS content, softening point and penetration prediction models with the same grade of asphalt exceeded 99%, 98% and 96%, respectively. It can be concluded that ANNs can provide well-satisfied regression models between the SBS content and infrared spectrum statistics sets, and the precision of penetration and softening point model founded by the same grade of asphalt is high enough to can meet the forecast demand. [ABSTRACT FROM AUTHOR]

The sustainable reuse of waste plastic as an alternative construction material has numerous environmental and economic advantages. New opportunities to recycle waste plastic in asphalt for road construction would mitigate landfill issues and significantly reduce global carbon emissions. With a clear aim to contribute to a more efficient reuse of waste plastic, this paper reutilized two types of waste plastic (polypropylene (PP) and polyethylene (PE)) as asphalt modifiers to improve the performance of asphalt pavement as well as to achieve the purpose of sustainable recycling waste plastic. Therefore, the optimal preparation parameters of plastic-modified asphalt were recommended by the orthogonal test. Then, the dispersion and modification mechanisms of plastic particles in plastic-modified asphalt were further studied by Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Differential Scanning Calorimetry (TG-DSC). The results show that the asphalt containing PP and PE shows better overall performance at high temperatures compared with the base asphalt. Furthermore, PE-modified asphalt and PP-modified asphalt exhibited optimal properties when prepared at 3000 rpm for 30 min at 170 °C. Moreover, the results of the expansion mechanism show that the main reaction process of plastic asphalt is a physical change. Finally, PP-modified asphalt and PE-modified asphalt generally perform well and are suitable for high-temperature areas. Consequentially, the results of this research promote the recycling of waste plastic, ultimately advocating the recycling of waste materials and environmental protection of pavement construction. [ABSTRACT FROM AUTHOR]

To prepare SBS modified asphalt (SMA) waterproofing membrane with excellent self-healing performance, in this paper, four self-healing agents (ASHA-A, ASHA-B, ASHA-C, ASHA-D) with acylhydrazone bonds and carbon-carbon double bonds (C C) were synthesized, and were used to prepare self-healing SMA waterproofing membranes (SSMA-A, SSMA-B, SSMA-C, SSMA-D). The effects of ASHAs with different structures on the structure, high and low temperature properties, joint peel strength and self-healing performance of SSMAs were investigated. The Fourier transform infrared spectroscopy and fluorescence microscope results showed that acylhydrazone bonds of ASHAs were introduced into the chains of SBS molecules, and the SBS in SSMAs occurred crosslinking through the C C of ASHAs and SBS, the crosslinked network structures of SBS in SSMA-C and SSMA-D were denser and more complete because ASHA-C and ASHA-D contained more C C involved in the crosslinking reaction. The softening point and low temperature flexibility of SSMAs were enhanced by the formation of the SBS crosslinked network structure, and the optimum dosage of ASHAs was 0.6%. The joint peel strength of SSMA-A, SSMA-B, SSMA-C and SSMA-D increased by 26.68%, 31.25%, 49.52% and 56.97% compared to SMA. The introduction of acylhydrazone bonds with reversible fracture and rearrangement significantly improved the crack self-healing performance of SMA, the impermeability times of SMA, SSMA-A, SSMA-B, SSMA-C and SSMA-D were 13.28 min, 37.29 min, 42.53 min, 53.34 min and 59.67 min after self-healing at 40℃ for 8 h, which indicated that ASHA-D with benzene ring and multiple C C had the best improvement in self-healing performance of SMA. [Display omitted] • Acylhydrazone self-healing agents with different structures were synthesized. • The introduction of acylhydrazone bonds improved the crack self-healing performance of SBS modified asphalt waterproofing membrane. • The effect of acylhydrazone self-healing agents on the properties of SBS modified asphalt waterproofing membrane was investigated. [ABSTRACT FROM AUTHOR]

In asphalt pavement thermal regeneration, incorporation of regenerant can restore the properties of aged SBS modified asphalt, but the effect of regenerant on the recovery of aged asphalt and the dosage of regenerant are not clear. In this study, experiments are carried to determine the effect of regenerant on the performance of aged SBS modified asphalt and the appropriate dose. Accelerated aging test is conducted by rolling thin film oven test (RTFOT) at different times. Then, different doses of regenerant (2 %, 4 %, 6 %, 8 %, 10 %, 12 %) are added to the specimens before and after aging, and test its technical indexes such as penetration, softening point and ductility to analyze the effect of regenerant on the properties of aged asphalt. The results show that: with the increase of the amount of regenerating agent, the aging asphalt performance indexes are restored, the softening point of regenerated asphalt is reduced, and the ductility and needle penetration are increased. Based on the analysis of the relationship between the aging time of SBS modified asphalt and the amount of regenerant, interpolation fitting is carried out to obtain the formula for the best amount of regenerant, so as to determine the best regenerant dosage for aged asphalt mixes in actual engineering applications. [ABSTRACT FROM AUTHOR]

This study resolves the poor enhancement problem of high‐temperature performance and lower dissolution of styrene‐butadiene‐styrene (SBS) modified asphalt and soybean bio‐asphalt (SBA) (extracted from waste soybean oil) by tannic acid (TA) modified bamboo fiber (MBF). The rheological properties and microscopic morphologies of the modified asphalt and fibers were investigated by dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR) tests, and Fourier transform infrared (FTIR) spectroscopy. The results showed that the rutting factor and deformation recovery rate of 3% MBF/3% SBS/SBA modified asphalt at 64°C increased by 78.4% and 31.99% as compared with those of 5% SBS modified asphalt. Further, the phenolic hydroxyl group of TA reacted with C═O groups in SBA to form a strong connection between BF and bio‐asphalt. Fluorescence microscopy analysis revealed that SBS solubilization and BF formed a uniform and stable network structure in the modified asphalt. This study provides a useful, greener, and cost‐effective strategy for the effective utilization of industrial waste (BF and waste soybean oil) by converting into advanced functional materials for highway and construction industries novel and hence can concomitantly decrease environmental pollution and enhance energy conservations. [ABSTRACT FROM AUTHOR]

SBS modified asphalt (SBSMA) pavements have gained popularity worldwide due to their prominent performance. However, its maintenance and reconstruction projects will produce a large amount of reclaimed asphalt pavement (RAP) during the long-term service of asphalt pavement. Adding rejuvenators products is a common method to recycling RAP. However, conventional rejuvenators are typical component regulators applicable to recycling unmodified asphalt, while there is a poor regeneration effect for the aged SBS modified asphalt (A-SBSMA), because it cannot repair the degraded SBS polymer. Fortunately, reactive rejuvenator (RR) has achieved this breakthrough based on the research findings in recent years. It contains special compounds that have the ability to repair the degraded SBS. The vital questions to be investigated in the present review are how the four current systems of RR (epoxy system, isocyanate system, compound system and polymer system) affect A-SBSMA's properties and how well does its regeneration effect. Existing research indicated that RRs are favorable for the regeneration of A-SBSMA and have their respective characteristics. This review summaries various RR different regeneration mechanism, and analyzed its effects on physical properties, rheological properties, high and low temperature properties, and microscopic characteristics of A-SBSMA. Although research on RR is still in its infancy with a limited number of relevant studies, they show an excellent regeneration effect for A-SBSMA and hold a promising prospect. Overall, this review provides information on the feasibility of using RR as a sustainable SBSMA rejuvenator to promote conserving resources and reusing RAP. [Display omitted] • Traditional regenerant is not completely suitable for A-SBSMA regeneration. • RR can realize the re-crosslinking of SBS polymer fragments. • RR can comprehensively regenerate A-SBSMA performance. • RR has a unique regeneration mechanism for A-SBSMA. [ABSTRACT FROM AUTHOR]

To enhance the dispersion of graphene oxide (GO) in Styrene-butadiene-styrene (SBS) modified asphalt (SA) and the comprehensive physical properties of GO/SBS-modified asphalt (GSA), PEA-GO composites were prepared by grafting polyetheramine (PEA) onto GO for the preparation of PEA-GO/SBS-modified asphalt (PGSA). In this study, the chemical structure of PEA-GO was examined using fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The conventional properties of GSA and PGSA were analyzed. The effects of GO and PEA-GO on the high and low-temperature prevalent properties of SA were investigated by dynamic shear rheology (DSR) test and bending beam rheology (BBR) test. The adhesion properties of GSA and PGSA were investigated by surface free energy theory (SFE). The surface micro-morphology of GSA and PGSA and the dispersion state of GO in SA were analyzed using atomic force microscopy (AFM) and fluorescence microscopy (FM). The results showed that the characteristic absorption peaks of N-H, CH 2 -CH 2, and C-N appeared in the FTIR diagram of PEA-GO. A new peak appeared in the XPS diagram: C-N. The high-temperature performance, low-temperature crack resistance, and adhesion of PGSA were superior to those of GSA. The size of the "bee structure" in PGSA is larger than in GSA, and PEA-GO demonstrates uniform dispersion in SA. This study serves as a reference for fine-tuning graphene oxide (GO) at the microscopic level to enhance the physical properties of GSA. • A functional composite of polyetheramine grafted graphene oxide was successfully prepared. • The spatial site resistance effect of polyetheramine improves the dispersion of GO in asphalt. • PEA significantly improved the physical properties of GO/SBS modified asphalt. [ABSTRACT FROM AUTHOR]

Agroforestry solid waste bagasse fiber (BF) possesses sustainable, carbon-neutral characteristics when used as a reinforcement material for asphalt pavements. However, the incompatibility between BF and the asphalt matrix limits its wide application. This study proposes a strategy for cost-effective and environmentally friendly modification of fiber surfaces, aiming to transform a drawback into an advantage. That is, the lignin in BF, which affects the tensile strength of fibers, is dissolved by a deep eutectic solvent (DES) system, and then the lignin is reborn on the surface of the fibers with the assistance of tannic acid. Based on the hydrophobicity and free radical trapping properties of lignin, regenerated lignin is expected to act as a natural coupling agent between BF and styrene-butadiene-styrene (SBS) asphalt materials and as an anti-aging agent for asphalt. The experimental results showed that the modified BF realized the enhancement of asphalt interfacial compatibility and toughening of asphalt matrix. Specifically, the shear resistance, viscoelasticity and rutting resistance of the modified BF/SBS-modified asphalt were improved by 46.61%, 22.67% and 30.06%, respectively, and the UV aging susceptibility was decreased by 75.02% compared with that of the BF/SBS-modified asphalt. In conclusion, this work introduces a simple and practical strategy for enhancing the interaction between BF and asphalt, which is crucial for advancing biomass recycling and green transportation development. [Display omitted] [ABSTRACT FROM AUTHOR]

Salt erosion is an important negative factor on the performance deterioration of asphalt-based materials. The basic properties of asphalt in salt erosion environments have been extensively studied; however, there is a certain lack of research on the rheological property of styrene–butadiene–styrene (SBS) modified asphalt under various salt erosion conditions. This study aims to identify the rheology deterioration of SBS modified asphalt under the action of salt freeze–thaw or saline immersion cycles through laboratory experiments. Rheological properties and creep recovery properties of SBS modified asphalt were tested based on the dynamic shear rheometer, and their rutting resistance capacity and fatigue cracking resistance were analyzed. Viscoelastic properties and low-temperature property of SBS modified asphalt were investigated by Burgers model, Christensen–Anderson–Marasteanu model and glass transition temperature. Results showed that the rutting capacity increased by an average of 34.5% and 39.7% after 21 times salt freeze–thaw and saline immersion cycles, respectively, while the fatigue cracking resistance decreased by 34.2% and 40.1%. Multi-stress creep recovery test manifested that both salt erosion modes had slight influence on the creep recovery property. However, the non-recoverable creep compliance at 3.2 kPa decreased by 37.5% and 32.3% after 21 times salt freeze–thaw and saline immersion cycles, respectively. Based on glass transition temperature, the low-temperature performance of asphalt decreased significantly after salt erosion. The rheological behavior and damage degree of asphalt were different for different salt erosion modes. The study may provide a theoretical basis for the construction and maintenance of asphalt pavement in salt-rich areas. [ABSTRACT FROM AUTHOR]

The sustainable advancement and low-carbon application of asphalt pavement significantly benefit from the reutilization of waste SBS modified asphalt (SBSMA) mixtures. However, the high-efficiency rejuvenation of aged SBSMA (ASBSMA) remains a persistent challenge. In this study, a novel reactive rejuvenator was developed using waste cooking oil (WCO) and methylene diphenylene isocyanate (MDI) to restore asphalt components and reconstruct SBS structures in ASBSMA. Temperature Sweep, Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC) tests were conducted to investigate the rejuvenation effect and mechanism of ASBSMA. The results indicate that the incorporation of WCO restores the low temperature performance of ASBSMA, but adversely affects its high temperature performance. Conversely, the addition of MDI enhances the high temperature performance of ASBSMA, but an excessive dose of MDI has a negative impact on its low temperature performance. Chemical composition analysis shows that the rejuvenation by WCO is a physical dissolution and softening process, while MDI can react with the SBS aged products to produce long chain products with an amide structure and reconstruct the cross-linked structure of SBS. Although the temperature stability of rejuvenated SBSMA is not fully restored to its original state, it shows significant improvement compared with ASBSMA due to the reconstruction of SBS structure. This study effectively clarifies the reactive rejuvenation mechanism of ASBSMA, achieves the synergistic restoration of asphalt components and SBS structure, and contributes to high-efficient recycling of WCO and waste asphalt materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The contributions of components to system viscosity are quantitatively calculated. • Equilibrium swelling ratio is used as an evaluation index for compatibility. • Trans PB shows low mobility and complete network structure due to high regularity. • Trans PB shows strong adsorption and swelling due to large contact area with maltenes. • Viscosity and compatibility can be improved by increasing the trans PB content in SBS. Optimizing styrene–butadiene–styrene copolymer (SBS) design for pavement engineering is crucial for producing cost-effective SBS modifiers and improving road quality. Five types of SBS molecules were characterized using 1H NMR. The influence of SBS content and molecular structure on the viscosity and compatibility was explained by molecular mobility, shearing phase morphology, adsorption and swelling behaviors based on molecular dynamics. The results show that the viscosity contribution of SBS is determined by the SBS molecular structure and phase morphology. SBS with longer and more regular chain structure exhibits lower mobility, and a higher propensity for forming network structures, which enhances resistance to the disaggregation of polystyrene (PS) and disentanglement of polybutadiene (PB) during shear. Furthermore, the viscosity contribution of asphalt is determined by the adsorption between SBS and maltenes, as well as the competition between SBS and asphaltenes, which reduces the maltenes mobility and promotes the asphaltenes aggregation. With increasing SBS content, the adsorption strength between SBS and maltenes increases and SBS tends to form a network structure, leading to an increase in viscosity. SBS with high trans -1,4 PB content (SBS-t) exhibits the best viscosity contribution, owing to its exceptionally long and regular molecular chain. High maltenes content or a wide SBS distribution range increase the compatibility. SBS-t has the largest distribution range, resulting in the largest contact area and the best compatibility. [ABSTRACT FROM AUTHOR]

• Asphalt rheological properties of field and laboratory aging can be corresponding. • Rheological and microscopic properties differ between field and laboratory aging. • Early aging behavior can restore and simulate with laboratory aging. • Laboratory aging fails to fully simulate field aging behavior. In this study, the correlation and difference of Styrene-Butadiene-Styrene (SBS) modified asphalt rheological and microscopic performance under field aging and laboratory aging were analyzed. The asphalt recovery experiment obtained SBS modified asphalt after construction aging (CA), 1 year field aging (1A), and 5 years field aging (5A) as field aging samples. The SBS modified asphalt samples were obtained by laboratory aging methods: ultraviolet aging (UV), rotating film oven test (RTFOT), and pressure aging vessel (PAV). Dynamic shear rheometer (DSR) and bending beam rheometer (BBR) experiments were applied to test the SBS modified asphalt rheological performance, and infrared spectroscopy (IR) and fluorescence microscopy (FM) were applied to test the SBS modified asphalt microscopic performance. By contrasting the SBS modified asphalt correlation and difference in rheological and microscopic performance during field aging and laboratory aging, the conclusion demonstrates that the degree of rheological and microscopic performance after CA treatment is not significantly different from that after RTFOT treatment. However, from the micro performance analysis, the micro performance indexes of PAV (10H) and PAV (20H) were significantly lower than those of 1A and 5A, and the rheological and micro properties are different after accelerated aging. This suggests that accelerated aging can recover and simulate the behavior in the early stages of field aging, but with increasing age, accelerated aging cannot fully simulate the aging behavior in more complex situations, resulting in a lower degree of accelerated aging than in the mid- to late-stage field aging. [ABSTRACT FROM AUTHOR]

[Display omitted] • Propose a novel GPC-based method to assess the aging condition of SBS binder in RAP. • Find suitable chemical composition fingerprinting to estimate SBS binders' properties. • Clarify the change mechanism of polymer and asphaltene in SBS binder due to aging. As fossil energy sources gradually become depleted, the reclamation of recycled asphalt pavement (RAP) has received increasing attention. During the production process of recycled mixtures, the aging conditions of binders in RAP need to be measured prior to the mixing design process. The conventional method adopts chemical solvents, including trichloroethylene and toluene to extract and recovery binders in the RAP. And then measure the corresponding properties of RAP binders. However, the whole process is complicated and time-consuming, and the used chemical solvents are highly toxic and harmful to researcher's health. Some scholars have proposed some methods to test the aging condition of asphalt binders in the RAP directly without extraction and recovery using the novel observation instruments. However, these methods are not suitable for modified asphalt. At present, modified asphalt has been often used in the road construction,especially for SBS modified asphalt. As such, the present study aims to introduce a novel approach to test the aging conditions of SBS modified binders in the mixtures avoiding the extraction and recovery process based on gel permeation chromatography (GPC). For this purpose, the molecular weight distribution as well as the physical properties of modified asphalt and binders in the mixtures at various aging degrees were first analyzed using GPC test. The polymer and asphaltene content of asphalt binders derived from GPC test were found correlation well with the aging degrees and properties of asphalt binders. Following this, several estimation models correlating the polymer and asphaltene content with penetration, viscosity and rutting factor were established. The robustness of established models were verified using laboratory-aged asphalt mixtures with three different SBS modifier contents and two kinds of on-site RAPs. The verification results showed that the properties in the mixture were reasonably estimated. [ABSTRACT FROM AUTHOR]

• A novel RA combined with new SBSMA are used to recycle field-aged SBSMA. • RA can lessen the aging behavior of recycled SBSMA from the molecular structure. • Continuous performance grade of ASR 0.45 NS is restored effectively. Styrene-butadiene-styrene block copolymers (SBS) modified asphalt has been the main binder applied in the surface course of high-grade asphalt pavement. However, as more and more pavements are entering into the maintenance period, a mass of waste SBS modified asphalt mixtures are produced. To effectively restore the performance of field-aged SBS modified asphalt (SBSMA), a novel rejuvenator (RA) combined with fresh SBSMA was used in this research. The rheological properties of recycled SBSMA were investigated using dynamic shear and bending beam rheometer tests, and the micro characteristics were characterized by fluorescence microscopy, Fourier transforms infrared spectroscopy and chemical composition tests. The results indicate that RA can lessen the aging behavior of recycled SBSMA from the molecular structure, enhance the compatibility between SBS modifier and asphalt in recycled SBSMA. The combined utilization of RA and new SBSMA can effectively recover the high, intermediate and low temperature rheological properties of recycled SBSMA. Moreover, when the ratio of aged SBSMA with RA to new SBSMA is 0.45:1, the recycled SBSMA has the closest continuous performance grade to new SBSMA. [ABSTRACT FROM AUTHOR]

To comprehend the deterioration of adhesion property for styrene-butadiene-styrene (SBS) modified asphalt in salt-freeze-thawing environment, the surface microstructure and mechanical images of SBS modified asphalt were obtained by atomic force microscopy (AFM). Additionally, the change law of chemical composition of SBS modified asphalt in salt-freeze-thawing environment was studied by Fourier transform infrared spectrometer (FTIR) test. Ultimately, the deterioration mechanism of adhesion property of SBS modified asphalt in salt-freeze-thawing environment was revealed. The findings indicate that the phase state of multi-components in SBS modified asphalt exhibits a trend of "homogenization" after freeze-thaw cycles in NaCl solution, and the surface roughness of SBS modified asphalt gradually decreases, resulting in microstructural characteristics that are similar to those of base asphalt. The adhesion force of SBS modified asphalt experiences a significant decrease, while the Derjaguin-Muller-Toporov (DMT) modulus increases to various degrees. Furthermore, the range of variation in adhesion force is greater than DMT modulus. The carbonyl index and sulfoxide index of SBS modified asphalt increases by various degrees after coupling effect of salt erosion and freeze-thaw cycle, while the aliphatic index and butadiene index declines. The primary cause of the deterioration of adhesion performance of SBS modified asphalt under salt-freeze-thaw coupling effect is attributed to significant variations in the functional group index. • The influence of salt-freeze-thawing environment on microstructure characteristic of asphalt binder is discussed. • The influence of salt-freeze-thawing environment on adhesion property of asphalt binder is explored. • The change law of chemical composition of SBS modified asphalt under salt-freeze-thawing environment is explored. • The correlation between adhesion property and functional group index of SBS modified asphalt is established. • The deterioration mechanism of adhesion property of SBS modified asphalt in salt-freeze-thawing environment is revealed. [ABSTRACT FROM AUTHOR]

[Display omitted] • This provides a novel analytical approach for understanding the mechanism of improving the macroscopic properties of SBS-modified asphalt with nanomaterials. • The modification mechanisms of carbon nanomaterials on asphalt include both chemical reactions and physical mixing. • Carbon nanomaterials can promote the dispersion and cross-linking of SBS in the oil phase, as well as filling in the asphaltene. Based on the four-component separation technology of asphalt, the influence mechanism of carbon nanotubes (CNTs), graphene microsheets (GNPs) and graphene oxide (GO) in SBS-modified asphalt four-component was systematically analyzed by combining macroscopic properties and microscopic characteristics, as well as exploring the morphological distribution of SBS in asphalt four-component. According to the results of Fourier transform infrared spectroscopy and field emission scanning electron microscopy, the modification mechanism of asphalt by three types of carbon nanomaterials follows two pathways: chemical reaction and physical blending. The addition of CNTs, GNPs, and GO results in the destruction of long carbon chains of the saturated fraction in SBS-modified asphalt, and promotes the aggregation of SBS in the asphaltene, as well as its dense distribution and crosslinking in the oil fractions. The results of the fluorescence microscopy test and phase separation test showed that the dispersing effect of the three carbon nanomaterials could alleviate the aggregation phenomenon of SBS, improve the mutual integration between SBS and matrix asphalt, and promote the storage stability of SBS-modified asphalt. Therefore, based on the excellent mechanical properties of the three carbon nanomaterials and their promotion of filling and crosslinking of SBS in asphaltene, they have made significant contributions to the mechanical properties of carbon nanomaterials-composite SBS modified asphalt. This can also be demonstrated by DSR testing and conventional physical property testing. This study hopes to provide a viable analytical route for the use of nanomaterials in modulating the four-component structure and improving the properties of asphalt. [ABSTRACT FROM AUTHOR]

Highlights • Thermochromic microcapsule improves fatigue and aging resistances of both base asphalt and SMA. • Thermochromic microcapsule has few effects on rutting and cracking performances of SMA. • Thermochromic microcapsule can improve the aging resistance of both base asphalt and SMA. • Action mechanism of red thermochromic microcapsule on SMA is more complex than base asphalt. Abstract Thermochromic microcapsule is an innovative and promising asphalt modifier which can dynamically adjust its reflectivity to solar radiation in accordance with temperature. However, thermochromic microcapsule may exhibit different effects on base and modified asphalt binders due to the existence of modifiers. In this paper, the effects of thermochromic microcapsule on rheological and aging behaviors of base and styrene-butadiene-styrene copolymer (SBS) modified asphalt binders were compared. Pavement performance-related rheological tests such as continuous performance grade (PG) grading, multiple stress creep recovery (MSCR), linear amplitude sweep (LAS), shear stress relaxation (SSR) and temperature sweep (TS) were conducted by dynamic shear rheometer (DSR) or bending beam rheometer (BBR) to evaluate rutting, fatigue, cracking and aging resistances of base and SBS modified asphalt binders influenced by thermochromic microcapsule. In addition, aging susceptibilities of asphalt binders were further analyzed by tracking the carbonyl increment after aging. The results indicated that thermochromic microcapsule improved fatigue resistances of both base and SBS modified asphalt binders while improving effect on base asphalt was more obvious than SBS modified asphalt binder. Different from base asphalt binder, SBS modified asphalt binder was almost not influenced by thermochromic microcapsule in terms of rutting and cracking performances. Like base asphalt binder, aging resistance of SBS modified asphalt binder was improved due to the introduction of thermochromic microcapsule. However, the influence of thermochromic microcapsule on anti-aging behaviors of SBS modified asphalt binder was more complex in comparison with base asphalt due to the existence of SBS modifier. [ABSTRACT FROM AUTHOR]

Due to the segregation of asphalt pavement, the damage of asphalt pavement always starts from locality. The viscosity of the 30# asphalt is always relative higher, which may cause more worries about the segregation of the 30# asphalt mixtures. During the construction of Jin-Hai highway in Fujian province of China, three test roads were constructed, two of them were constructed with the 30# low penetration asphalt and one with SBS modified asphalt. Other factors, such as different construction technologies, source of asphalt, sources of aggregates and types of bearing layers, may affect the segregation of asphalt pavement were also investigated. In addition, two calibration methods were investigated to ensure a better calibration method for the calibration of the pavement quality indicator (PQI). The results show that it is of great benefits to use PQI as an on-site monitoring during the construction of asphalt pavement, the Method 1 is recommended as the calibration method for the PQI. The 30# low penetration asphalt mixture has a good construction performance, the 5.5 cm thickness of 30# low penetration asphalt concrete will not appear some specific segregation situation s by the trapezoid paving method. [ABSTRACT FROM AUTHOR]

The composite modified asphalt was produced by high speed shearing method and the mixing amounts of crumb rubber were respective 7%，10%，13% and 16%. The results show that according to the three major indexes of asphalt and creep tests with bending beam rheometer, the high temperature stability of the modified asphalt is better than that of the single SBS modified asphalt, while the low temperature performance is not improved. The dynamic shear rheological tests show that the viscoelastic properties of composite modified asphalt are also improved. The experimental results of modification mechanism by fluorescence microscopy and infrared spectroscopy indicate that the physical swelling reaction occurs in the process of modification with the rubber changing from granular to mesh. There is no new functional group, but the peak value of infrared spectrum characteristic peak changes, indicating that the reaction process has chemical bond open under the conditions of high temperature and high speed shear. Combining macro and micro tests, the appropriate dosage of rubber is 10% to 13%. [ABSTRACT FROM AUTHOR]

Highlights • Thermochromic powders had a slight effect on high-temperature properties of SBS modified asphalt. • Thermochromic powders could improve low-temperature performance of SBS modified asphalt. • Thermochromic powders could significantly improve the aging resistance of SBS modified asphalt. Abstract Styrene-butadiene-styrene copolymer (SBS) modified asphalt is widely utilized in road construction. However, aging effect on SBS modified asphalt is still a serious problem that needs to be resolved. It has been demonstrated that thermochromic materials can-not only adjust the road surface temperature, but also improve the aging resistance of base asphalt. This paper mainly investigated the effects of different content (0, 2, 4, 6, 8%) of red thermochromic powders (RTP) on the thermal oxidizing aging of SBS modified asphalt. Thin film oven test (TFOT), pressure aging vessel test (PAV) and ultraviolet radiation (UV), were used to simulate thermo-oxidative aging and ultraviolet aging of RTP binders, respectively. Physical and rheological properties of RTP binders before and after three aging methods were discussed. The results displayed that the red thermochromic powders had a slight effect on high-temperature stability of SBS modified asphalt, while the low-temperature performance grade of the SBS modified asphalt could be improved with the introduction of RTP. Aging behaviors of RTP asphalt binder could be effectively prevented in comparison with blank sample, indicating its good aging resistance which is in accordance with changes in physical and rheological properties of the binders before and after aging. In addition, 2% and 4% RTP binders showed superior aging resistance than 6% and 8% RTP binders. [ABSTRACT FROM AUTHOR]

The effects of different types (red, black and blue color) and content (2% and 4%) of thermochromic powders on aging properties of styrene-butadiene-styrene copolymer (SBS) modified asphalt were investigated. Physical properties of the binders (ductility, penetration, viscosity and softening point) were tested before and after thermal-oxidative and ultraviolet radiation aging. The results showed thermochromic powders improved the deformability and weakened the high-temperature performance of SBS modified asphalt to some extent. Thermochromic powders could obviously improve the anti-aging properties of SBS modified asphalt. In addition, SBS modified asphalt with 2% thermochromic materials showed the best aging resistance under all aging modes. [ABSTRACT FROM AUTHOR]

Highlights • The effect of adding Naphthenic oil into SBS modified asphalt was compared with adding Nano-MMT. • An ‘ingredients microstructure’ model was proposed for SBS modified asphalt. • The influence of naphthenic on SBS modified asphalt was divided into three stages while only one for Nano-MMT. • Naphthenic oil takes effect as a supplement for maltene. Abstract Naphthenic oil is an organic solvent whose effect as an additive to SBS modified asphalt is rarely studied. The influence of naphthenic oil on SBS modified asphalt was investigated in the paper. The influence of a well-known inorganic solid additive, Nano-MMT, was also studied to make a comparison. Storage stability, low/high temperature properties, and rheology were tested with different additive dosages. It is found that the storage stability of SBS modified asphalt can be improved by both Nano-MMT and naphthenic oil. Low temperature property is improved by naphthenic oil but worsened by Nano-MMT. High temperature viscosity is enhanced by naphthenic oil and decreased by Nano-MMT. High temperature sensitivity reflected by softening point and rutting factor increases with Nano-MMT, while it rises first then falls with naphthenic oil. An ‘ingredients microstructure’ model was proposed to describe the microstructure of ingredients of SBS modified asphalt. The model considers SBS modified asphalt to consist of two domains; one is the bee structures domain which contains maltenes inside, the other one is maltene domain which also contains asphaltenes. SBS which is smaller than the bee-like structure is randomly distributed in the maltene. Under the proposed model, the mechanism of naphthenic oil is divided into three stages considering the variation of dosage of naphthenic oil, while the effect of Nano-MMT has only one stage. It was found that the model proposed can explain the changes in storage stability and properties of SBS modified asphalt. It is proved practical to consider naphthenic oil as a supplement for maltene, taking effect in the mixture as saturates and aromatics. [ABSTRACT FROM AUTHOR]

The cross-linked network present in crumb rubber (CR) limits its uniform dispersion in styrene-butadienestyrene modified asphalt (SBSMA). For this purpose, CR was degraded using a twin screw extruder to improve its dispersion properties in SBSMA. Different degraded rubbers (DR) prepared at different degradation temperatures were blended with SBSMA. Interaction in asphalt, SBS and degraded rubber were analyzed and compared using thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The degradation behavior, glass transition temperature and the low temperature rheological properties of the modified asphalt were evaluated. The results indicate that the degree of degradation in the CR affects its dispersion and interactions with SBSMA, which further influences the performance of the modified asphalts. The morphological analysis explains the mechanism of interactions within the degraded rubber, asphalt and SBS, specifies that the modification of the asphalt occurs via the exchange of materials among these three components. [ABSTRACT FROM AUTHOR]

[Display omitted] • The reaction conditions have great influence on the performance of SBS modified asphalt. • The stabilizer content is the key factor for the performance improvement of SBS modified asphalt. • The PB segment in the SBS polymer participates in the chemical reaction. • The cross-linking percentage of SBS modified asphalt is about 13%. Recently, the batch production of styrene–butadienestyrene (SBS) modified asphalt has been realized, but quality control is still in the empirical stage. While the chemical reaction position and the cross-linking degree are unclear, affecting the controlling quality of SBS modified asphalt. Therefore, this study investigated the influence of the reaction conditions and the stabilizer content on the performance and morphology of the SBS modified asphalt. And whether the chemical reaction exists and the chemical reaction position were confirmed by preparing the polystyrene (PS) monomer, polybutadiene(PB) monomer, and SBS modified asphalt with and without stabilizer. Finally, the fluorescence microscope (FM) test, Fourier transformation infrared spectroscopy (FTIR) test and the chemical titration method were used to characterize quantitatively the microstructure changes of SBS modified asphalt. The results show that the reaction conditions greatly influence the performance of SBS modified asphalt. After adding the stabilizer, the phase state of the system changed from the SBS phase as a dispersed phase and the asphalt phase as a continuous phase to the double continuous phase, and the network structure was formed. The chemical reaction has taken place in the PB and SBS modified asphalt, and the PB segment of the SBS polymer participates in the chemical reaction. Furthermore, the degree of cross-linking reaction of SBS modified asphalt is low, and the range of the cross-linking percentage is about 12.3%-14.5%. [ABSTRACT FROM AUTHOR]

• The multi-scale study was conducted on the adhesion properties of the WMRA. • The effect of aged SBS modified asphalt content on the adhesion properties of the WMRA in macroscopic and microscopic scales was studied. • The micromorphology and nano-adhesion of WMRA were studied with AFM technology. • The pull-off strength of WMRA exhibited an excellent correlation with the adhesion roughness index R a of WMRA. The adhesion properties have been a major concern of warm mix recycled SBS modified asphalt. This study aims to evaluate the adhesion properties of warm mix recycled SBS modified asphalt on multi-scale. Three kinds of asphalt (blends of aged and unaged SBS modified asphalt [AUA], AUA with rejuvenator [ARA], and ARA with warm additive [WMRA]) were prepared. The effects of the content of aged SBS modified asphalt, rejuvenator and wax-based warm additive on the adhesion of WMRA were investigated using the pull-off test and surface free energy theory. The micromorphology and nano-adhesion were measured by atomic force microscopy (AFM), and the test data were compared with macroscopic adhesion. The results showed that the Lewis acid component of AUA increased with the raised content of aged SBS modified asphalt. The wax-based warm additive caused a decrease in the Lewis acid component, which caused the adhesion work of WMRA to be lower than that of AUA and ARA. When the content of aged SBS modified asphalt was low, the rejuvenator could improve the adhesion of AUA and reached a peak at 20%. After adding the wax-based warm additive, the microscopic surface of WMRA showed irregular and non-uniform morphological characteristics, and the bee structure was unclear and gathered to form an island-like structure. The crystallization of wax-based warm additive on the asphalt surface caused the increased of WMRA on nano-adhesion and roughness indexes. The adhesion work and adhesion roughness index R a could be used to evaluate the adhesion of the WMRA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Innovative apply MXene in the field of UV resistance of ecological road materials. • Expound on the interaction mechanism of MXene, SBS and asphalt. • Clarify the UV shielding mechanism of MXene/SBS modified asphalt. • Analyze the effect of regulation and control of MXene properties on UV resistance of modified asphalt. The pursuit of improving the special properties of modified asphalt using advanced nanomaterials and understanding its mechanism based on material properties is highly attractive topic. In this study, four types of MXene (Ti 3 C 2 Tx) (prepared by adjusting the synthesis methods) were incorporated into styrene–butadienestyrene (SBS) block copolymer modified asphalt as ultraviolet (UV) aging resistant modifiers. The UV aging behaviors, such as asphalt photo-oxidation and SBS copolymer degradation, were evaluated by simulating UV aging of modified asphalts using indoor equipment. The chemical and rheological results showed that MXene incorporated modified asphalts had excellent high-temperature performance and rutting resistance. Furthermore, MXene incorporation significantly inhibited asphalt oxidation and SBS copolymer degradation. The underlying mechanism of these intriguing properties was found to be the few-layered structure and -F, -O surface end groups of MXene, which were the key factors responsible for the enhanced anti-UV aging performance of modified asphalt. [ABSTRACT FROM AUTHOR]

Perennial freeze-thaw cycles have caused plenty of defects on asphalt pavements. To analyze the effect on asphalt binder and mastic under freeze-thaw cycles, the multiple stress creep recovery (MSCR) tests, frequency sweep tests, linear amplitude sweep (LAS) tests, and bending beam rheological (BBR) tests were performed first. The rheological property of asphalt binder and mastic was evaluated through the Burgers model, 2S2P1D (two springs, two parabolic elements, and one dashpot) model, Sigmoidal model, and viscoelastic continuum damage (VECD) theory. The Einstein coefficient and K. D. Z i e g e l − B − G ∗ (K − B − G ∗ ) model were adopted to investigate the asphalt binder-filler interaction subsequently. Finally, Fourier transform infrared spectroscopy (FTIR) test was conducted to analyze the variation of chemical composition of asphalt binder before and after freeze-thaw cycles. The results showed that as freeze-thaw cycle increased, the percent recovery of asphalt binder increased, and the non-recoverable creep compliance of asphalt binder decreased and that of asphalt mastic increased first but decreased. The rutting factor and fatigue factor of asphalt binder and mastic increased after freeze-thaw cycles. The asphalt mastic showed poorer fatigue resistance than asphalt binder at a given freeze-thaw cycle. The low-temperature stiffness of asphalt binder and mastic increased as freeze-thaw cycle increased. K − B − G ∗ value showed that the asphalt binder-filler interaction damaged seriously after fifteen freeze-thaw cycles, and the Einstein coefficient decreased by 52.73% after twenty freeze-thaw cycles. The I S and I C indexes increased, and the I B index decreased after twenty freeze-thaw cycles. The design and construction of asphalt pavement in seasonal frozen regions may benefit from this study. [Display omitted] • The effects of freeze-thaw cycles on asphalt binder and mastic were investigated. • The rheological properties of asphalt binder and mastic were compared and evaluated. • Freeze-thaw cycles caused accelerated damage from asphalt binder-filler interaction. • The asphalt binder's chemical composition was affected by freeze-thaw cycles. • The effects of interaction and chemical variation on asphalt property were observed. [ABSTRACT FROM AUTHOR]

Layered double hydroxide (LDH) could improve the aging resistance of an asphalt binder. However, the previous work all arbitrarily selected only one dosage of LDH such as 3% or 5%, which could not be enough to know the effect of LDH and its dosage on the pavement performance and aging resistance of an asphalt binder accurately, it is important to investigate the LDH effect on the properties of asphalt from more widely ranges of dosages. Meanwhile, the LDH and asphalt binder interaction is still unclear. In this paper, six dosages (from 2% to 7%) of Mg-Al-CO 3 2− -LDH were conducted to modify the styrene-butadienestyrene modified asphalt (SBS MA). The Fourier transform infrared spectroscopy (FTIR) and X ray diffraction (XRD) results indicate that there is no chemical reaction between LDH and SBS MA, the blending of LDH and SBS MA is a physical way. The rheological properties of SBS MA are studied by both dynamic shear rheometer (DSR) and bending beams rheometer (BBR), the results show that LDH can improve the high temperature performance of SBS MA, and does not significantly weaken other properties of SBS MA by controlling LDH dosage to be lower than 4%. The FTIR, complex modulus and VAI results show that LDH can significantly improve both the thermal oxide aging and UV aging resistances of SBS MA. LDH dosage of 4% is suggested to be the optimal dosage after considering the effect of LDH on the aging resistance and pavement performance of asphalt binder. [ABSTRACT FROM AUTHOR]

To improve the low-temperature and anti-fatigue performances of the bridge deck pavement and decrease its cost, an unsaturated polyester resin (UPR) modified asphalt mixture is put forward in this paper. First the optimum formula of UPR modified asphalt is determined through several tests. Second the ductility, bending beam rheometer (BBR), dynamic shear rheometer (DSR) and tensile tests are conducted for matrix asphalt, and SBS, epoxy and UPR modified asphalts. Finally, Marshall, rutting, low temperature bending, freeze-thaw splitting and fatigue tests are conducted for their mixtures. Test results show that the laboratory performances of UPR modified asphalt mixture are more excellent than those of SBS modified asphalt mixture and have advantages over those of epoxy modified asphalt mixture in low-temperature crack resistance, water stability and anti-fatigue ability. The maximum flexural-tensile strain, stripping inflection point and fatigue life of UPR modified asphalt mixture are 2.54, 1.25 and 1.08 times of those of epoxy modified asphalt mixture, respectively. Whereas the cost of UPR modified asphalt is only 62% of that of epoxy modified asphalt. Although the BPA will have a certain impact on the health of BPA unsaturated polyester resins production workers and construction workers, this impact can be controlled by limiting BPA concentrations within reasonable ranges and taking effective protective measures. [ABSTRACT FROM AUTHOR]

The simultaneous polymer degradation and asphalt oxidation of polymer modified asphalt (PMA) binder make it difficult to understand the rheological behavior of PMA in the aging process. The present study was meant to investigate the rheological behavior of various PMAs before and after aging (Rolling Thin Film Oven Test (RTFOT) and Pressure Aging Vessel (PAV)) by using rheological master curves in combination with Gel Permeation Chromatography (GPC). The GPC test was performed to obtain the average molecular weight (Mw) of the polymer and distribution of asphaltenes and maltenes. The properties of chemical and rheological were analyzed comprehensively and the results indicated that the phase angle (δ) is more sensitive to asphalt composition (sulfur contents, polymer and base binder characteristic) than the complex shear modulus. Besides, the δ shape can strongly reflect the differences between the rheological responses of the modified asphalts under the different aging conditions. A plateau would occur if the SBS network was formed. Thus the δ shape of SBS modified asphalt will be closer to that of base binder when SBS structure was completely destroyed. Although the degradation of polymer became severer when sulfur was added, sulfur can promote the formation of three-dimensional structures of styrene–butadiene–styrene (SBS) and improve the rheological property of aged PMAs. [ABSTRACT FROM AUTHOR]

Low temperature properties of the styrene-butadiene-styrene (SBS) modified asphalt binder and aged SBS modified asphalt binder containing rejuvenators were investigated using conventional methods (penetration and ductility at 5 °C), Fraass breaking point test, dynamic shear rheometer (DSR), force ductility test and bending beam rheometer (BBR). Effects of the aging and the contents and characteristics of the rejuvenator on these properties were studied. The results indicated that aging declined low temperature properties of SBS modified asphalt binder, and the rejuvenators improved low temperature properties of aged SBS modified asphalt binder. The degrees of improvement increased with rejuvenator content and were influenced by rejuvenator type. The study also showed a statistically linear correlation between different low temperature parameters. But the penetration at °C may not a good parameter to evaluate the low temperature properties of asphalt binder. [ABSTRACT FROM AUTHOR]

Highly reclaimed rubber (HRR)/SBS modified asphalt (HRRMA) technology is planned to endow the advantage of aging resistance of HRR to SBS modified asphalts. The effect of content and type of HRR, reclaim degree and vulcanization on morphologies, physical properties and aging behavior of SBS modified asphalt were investigated. The characteristics and distribution of major functional groups of HRRMA before and after thermal aging and UV aging were analyzed by infrared spectrum. Rheological properties of HRRMAs are characterized by using dynamic shear rheometer (DSR). Addition of HRR in SBS modified asphalt showed increase in penetration values before and after short term aging and UV aging. HRR reclaimed at higher temperature showed increased compatibility with asphalt, resulting in the increase of ductility, better thermal and UV aging resistance. Rheological properties of modified asphalt changed significantly after aging. Moreover, the morphologies of HRR modified asphalt showed it has better compatibility between SBS and HRR. Crosslinking further enhanced the ductility and aging resistance, whereas less increased the processing viscosity of the modified asphalt. The use of HRR in SBS modified asphalt is not only a cost-effective way to recycle waste rubbers but also improve the aging resistance and physical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Separated the degradation of SBS from the oxidation aging of the matrix asphalt. • The protective effect of matrix asphalt on SBS is first enhanced and then weakened. • The SBS effective content in weathering aging follows an exponential decay function. • Established the conversion of the SBS effective content between different aging. Under the weathering environment, the aging behavior of SBS-modified asphalt (SBSMA) is complex, including oxidation of matrix asphalt, degradation of SBS, and disruption of SBS-asphalt interaction. However, most studies on the weathering mechanism of SBS-modified asphalt have mainly been considered from its overall perspective and based on environmental variables. In order to investigate the aging mechanism of SBSMA more clearly, the paper proposes a novel method of SBS-independent weathering to determine the aging behavior of SBS under accelerated weathering conditions and its effect on the performance of modified asphalt. Finally, by correlating its samples (M1) with the behavior of different fresh SBSMA(M2) and weathering aged SBSMA(M3), the SBS effective content equation under weathering conditions and the conversion coefficient between different aging methods were determined. Furthermore, by analyzing the physicochemical properties of SBS polymers before and after weathering and comparing them with the calculated results of SBS effective content within modified asphalt, it is discussed that the swelling effect of SBS under this method differs due to different aging levels, which affects the complete separation of matrix asphalt oxidation and SBS degradation. The macroscopic rheological behavior of samples was evaluated by dynamic shear rheology experiments (DSR), the variation of their chemical component and molecular weight were analyzed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC), and the microscopic network was observed by fluorescence microscopy (FM). The results illustrate that the degradation pattern of weathering SBS follows a single exponential decay function. The SBS effective content decreases to 66.7 %, 50 %, and 33.3 % after accelerated weathering for 5.8 h, 10.5 h, and 14.5 h, respectively. In addition, the conversion relationship between the effective content of SBS under two modes of SBS independent weathering aging and SBSMA weathering aging was established. The effective content of SBS within SBSMA at different service stages and its remaining modification capacity can be reasonably predicted by simple SBS weathering tests. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effects of capsules on self-healing ratios of base and SBS modified asphalt mixtures were studied. • Oil release ratios after compaction were 5.7% and 7.0% for base and SBS modified asphalt mixtures. • Capsules in SBS modified asphalt concrete released oil more rapidly under loading. • Both base and SBS modified asphalts were rejuvenated by the capsules. • SBS modified asphalt concrete containing the capsules showed lower healing ratio. Calcium alginate capsules can gradually release healing agent and heal cracks in asphalt mixtures under vehicle loading. However, the current research is focusing on how calcium alginate capsules affect the self-healing abilities of base asphalt mixtures. It is still unclear whether calcium alginate capsules can be utilized to rejuvenate and heal SBS modified asphalt mixture. Through a three-point bending (3 PB)-cyclic compression loading-3 PB test, the effects of calcium alginate capsules on the self-healing characteristics of base and SBS modified asphalt mixtures were examined and compared in this study. Fourier transform infrared spectroscopy (FTIR) and dynamic shear rheometer (DSR) tests were conducted on extracted asphalt binders to study the release behaviors of the capsules within different asphalt mixtures and their regeneration effects on the asphalt binders. The findings demonstrate that under cyclic compression loading, calcium alginate capsules can greatly enhance the strength recovery ratios of base and SBS modified asphalt concretes. The capsules in SBS modified asphalt concrete released the oil more rapidly than in base asphalt concrete probably due to the higher mixing temperature. Both the base and SBS modified asphalts can be rejuvenated by the oil released from the capsules. However, SBS modified asphalt concrete containing the capsules showed lower strength recovery ratios than base asphalt concrete due to lower flow ability of SBS modified asphalt and incapacity of the capsules to repair the broken SBS polymer network. [ABSTRACT FROM AUTHOR]

This paper establishes a new model to evaluate the stability of SBS modified asphalt based on quantitative analysis of microstructure. The model considers both the vertical separation level and horizontal separation level, making it a more comprehensive one. The comprehensive evaluation index ϕ T,t in the model can better describe the influence of temperature and time on stability of SBS modified asphalt. At the temperature of 30 °C, 60 °C, and 120 °C, ϕ T,t shows a relationship with time which agrees with the logistic curve. The regular macro stability test was also carried out to verify the accuracy of the model. The curves of Softening Point Difference vs. time derived by the proposed model show a satisfactory agreement with the experiment-based curves, which proves the accuracy of the new model and the relationship between micro and macro stability index as well. [ABSTRACT FROM AUTHOR]

Styrene-butadiene-styrene copolymers (SBS) modified asphalt has been widely used for extending the service life of pavement. Understanding the natural weathering mechanism of SBS modified asphalt (SBSMA) is useful for both the extension of service life and recycling SBSMA pavement. The natural weathering process of base asphalt (BA) and SBSMA is traced by characterizing the rheological and structural evolution of different aged asphalts. Artificial aging such as rolling thin film oven test (RTFOT) and UV aging is compared with the weathering process. Infrared spectroscopic, gel permeation chromatography and dynamic shear rheometer are used to analyze this evolution. The results illustrate that significant changes occur in the chemical structures and rheological properties of SBSMA during natural weathering process. SBSMA shows the same aging trend as BA in terms of rheological and chemical evolution. The SBSMA aging is more serious than BA when comparing the aged ratio of rheological properties, whereas BA is more serious when comparing the ratio of carbonyl index. Furthermore, the molecular condensation is dominant in aging of BA than that of SBSMA. Comparing artificial aging and natural weathering of SBSMA, it is noted that RTFOT and UV aging could not completely simulate the natural weathering behavior of SBSMA. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the effect of the warm compaction modifier on the physical and rheological properties of High-viscosity High-elasticity modified asphalt and SBS modified asphalt. Three types of asphalt binder with different concentrations (at 0.3%, 0.5%, 0.8% by weight) of the warm compaction modifier were studied respectively. The influence of the warm compaction modifier on the physical and rheological properties was evaluated by penetration, softening point, and ductility and Dynamic Shear Rheometer (DSR) test. It was evident that the addition of the warm compaction modifier had a significant effect on the stiffness and elasticity behavior of the asphalt both at high and intermediate temperatures. It is indicated by DSR analysis that the warm compaction modifier could increase stiffness and fatigue behavior compared with base modified asphalt. Based on the physical and rheological tests, the concentration of warm compaction modifier was recommended to be at 0.3% by the weight of base modified asphalt. [ABSTRACT FROM AUTHOR]

The aging hardening of neat asphalt binder and the aging degradation of styrene-butadiene-styrene (SBS) polymer could significantly shorten the service life of the SBS modified asphalt (SBSMA) pavement and produce vast waste asphalt pavement materials. In order to recycle and reuse the aged SBSMA in a sustainable way, a green compound rejuvenator, which consists of aromatic oil and triallyl isocyanurate (TAIC), was developed to restore the original properties of the aged SBSMA based on the synchronous rejuvenating mechanism (i.e., colloidal structure regulation and SBS polymer structural reconstruction). The rejuvenating efficiency of the newly developed compound rejuvenator was first verified by fluorescence images, functional group characteristics, and molecular weight distributions of the SBSMA before and after rejuvenation. The rheological properties of the synchronous rejuvenated SBSMA (SRSBSMA), including the high-temperature permanent deformation resistance, low-temperature anti-cracking resistance, and fatigue resistance performance, were subsequently tested and compared with those of the SRSBSMA developed in previous studies. The results showed that aromatic oil had the capability to stabilize the unbalanced colloidal structure of the aged neat asphalt binder, while TAIC underwent a chemical reaction with the active group of the aged SBS to reconstruct the crosslinking network structure of the SBS modifier. Additionally, the rheological test results indicated that the performance of SRSBSMA restored by the new compound rejuvenator was the closest one to that of the virgin SBSMA as compared with the existing rejuvenators. To this end, the newly developed compound rejuvenator is proven to be promising in restoring the properties of SBSMA, which thus can be used to efficiently rejuvenate the aged SBSMA pavement. The schematic diagram of sustainable development for the asphalt pavement and the crosslinking network structure evolution of SBS polymer in its service and active rejuvenation. [Display omitted] [ABSTRACT FROM AUTHOR]

• OATP enhances high temperature performance of SMAWM. • Compared with ATP, OATP has less influence on low-temperature performance of SMAWM. • OATP significantly improves thermal and UV aging resistance of SMAWM. In order to improve the aging resistance of styrene butadiene styrene (SBS) modified asphalt waterproofing membranes (SMAWM), in this study, vinyltriethoxysilane grafted attapulgite (VTES-g-ATP) and octadecyl-dimethyl-benzyl-ammonium chloride intercalated attapulgite (ODBA-i-ATP) was prepared, respectively. The effects of VTES-g-ATP and ODBA-i-ATP on properties of SMAWM before and after thermal and ultraviolet aging were investigated. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and loss on ignition test indicated that the cationic surfactant octadecyl-dimethyl-benzyl-ammonium chloride (ODBA) was intercalated into the porous structure of attapulgite (ATP), while the coupling agent vinyltriethoxysilane (VTES) was grafted on the surface of ATP. The water contact angles of ATP, VTES-g-ATP and ODBA-i-ATP were 0°, 50.25° and 72.25°, respectively, revealing VTES-g-ATP and ODBA-i-ATP had better hydrophobicity. Compared to ATP, VTES-g-ATP and ODBA-i-ATP effectively improved the softening point and viscosity and had less effect on the low-temperature flexibility of SMAWM. The results of thermal and ultraviolet aging showed that VTES-g-ATP and ODBA-i-ATP were superior to ATP in enhancing aging resistance of SMAWA, particularly ODBA-i-ATP. FTIR analysis showed that ATP, VTES-g-ATP and ODBA-i-ATP effectively inhibited the oxidative polycondensation of asphalt and the degradation of SBS. Considering the balance of physical properties and aging resistance of modified SMAWM, the ODBA-i-ATP was more suitable as an additive for SMAWM, and the optimal dosage of ODBA-i-ATP in SMAWM is 3.0 wt%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Innovative application of APTES, co-deposition of PEI and PDA in the modification of polyacrylonitrile fibers. • Double-layer membrane structure modified polyacrylonitrile fibers. • P-P/A-P/PAN and A-P/PAN with higher surface free energy, roughness and adhesion. • P-P/A-P/PAN/SBS@MA and A-P/PAN/SBS@MA had better viscoelastic properties. • P-P/A-P/PAN/SBS@MA and A-P/PAN/SBS@MA had better low temperature crack resistance and high temperature adhesion properties. To further enhance the properties of polyacrylonitrile (PAN) fiber incorporated modified asphalt, a new method of PAN fiber modification with a double membrane was developed. The influence of interface characteristics of modified fiber on the properties of fiber-reinforced asphalt was revealed from the free energy of the fiber surface and the adhesion between the modified fiber and matrix asphalt. Two types of PAN modified fibers with single-layer membrane structure (A-P/PAN) and double-layer membrane structure (P-P/A-P/PAN) were prepared, which were applied to synthesize three types of modified asphalts (Mas), i.e., PAN/SBS@MA, A-P/PAN/SBS@MA, and P-P/A-P/PAN/SBS@MA. Dynamic shear rheometer (DSR) experiment showed that at 46℃, the G*, G', and G' of P-P/A-P/PAN/SBS@MA were 24%, 19%, and 37% higher than those of PAN/SBS@MA. Similarly, at 175 ℃, the maximum yield strength of P-P/A-P/PAN/SBS@MA was 16.38% and 32.7% higher than those of A-P/PAN/SBS@MA and PAN/SBS@MA, respectively, which was attributed to the better surface free energy and adhesion work of the modified fibers. The surface contact angle test results showed that free energy of the surface and adhesion work of P-P/A-P/PAN fibers are 62% and 26.5% higher than those of PAN fibers, respectively. Scanning electron microscopy, atomic force microscopy, and UV-Vis tests indicated that the fiber's surface has successfully constructed a double-layer membrane structure. The fluorescent microscopy and cryo-SEM tests of the modified asphalt further confirmed that the modified PAN fiber had better interfacial interaction with the base asphalt. This study shows that the double-layer film modified PAN fiber composite SBS asphalt has good viscoelastic properties, high temperature adhesion, and low temperature fracture resistance, and hence carries critical practical engineering applications for highways, low temperature area pavements, airport pavements, and construction pavement. [ABSTRACT FROM AUTHOR]

Rubber asphalt (RA) and styrene–butadiene–styrene (SBS) modified asphalt are widely used for all roads grades. However, the fumes generated by RA preparation as well as the high cost of SBS modified asphalt have limited their widely development. To address these challenges, desulfurized rubber powder (DRP) was developed as a cheap and clean modifier. Herein, DRP and SBS were applied to produce composite modified asphalt. Afterward, experiments were performed to evaluate the performances of the resulting blend. The basic physical properties of the DRP/SBS composite modified asphalt were satisfactory when DRP and SBS comprised 15% and 4% of the blend, respectively. Regarding the road performances, the DRP/SBS composite modified asphalt mixture performed much better than SBS modified asphalt mixture. Moreover, microcosmic property tests and inorganic fume emission monitoring indicated that the DRP/SBS composite modified asphalt reduced fumes because of the stable chemical bonding of DRP, absorption of the light components, and increased swelling. Finally, the DRP/SBS composite modified asphalt and its mixture significantly reduced SO 2 emissions by more than 40% and NO 2 and NOx emissions by more than 50%, which demonstrated their potentially significant contributions toward field construction application and environmental protection. [ABSTRACT FROM AUTHOR]

[Display omitted] • HAP-PDA on the surface of RP was grown by in situ biomimetic mineralization. • HAP-PDA-RP/SBS-MA was prepared via a facile and convenient strategy. • HAP-PDA-RP/SBS-MA exhibited improved mechanical performance, rutting resistance. • Enhanced performance of HAP-PDA-RP/SBS-MA was attributed to new network structure. Based on the impact resistance of hydroxyapatite (HAP) and the adhesion of polydopamine (PDA), in situ biomimetic mineralization strategy was used to grow HAP-PDA coatings on the surface of rubber powder (RP) to prepare HAP-PDA-RP, which was in turn applied as a modifier to prepare styrene–butadienestyrene (SBS) modified asphalt (SBS-MA). XRD, Raman and XRF analyses confirmed the successful synthesis of HAP monomers. EDS and SEM showed that HAP-PDA is successfully attached to the surface of RP while FM test revealed a clear cross-linked network structure in HAP-PDA-RP modified SBS-MA (HAP-PDA-RP/SBS-MA). DSR test results indicated that at 46 °C, the storage modulus and loss modulus of 15%HAP-PDA-RP/SBS-MA were 27.9% and 24.5% higher than those of 10%RP/SBS-MA respectively. MSCR tests showed that compared to the strain of SBS-MA, the strain of 15%HAP-PDA-RP/SBS-MA was decreased by 78.5% and 65.0% at 0.1 kPa and 3.2 kPa stress levels, respectively. This study provided a facile and convenient strategy for the preparation of HAP-PDA-RP/SBS-MA with significantly superior mechanical and thermal properties for practical applications in construction and road industries. [ABSTRACT FROM AUTHOR]

• Developed coarse grained models to study interaction between asphalt and SBS with different molecular structures. • Validated model results through asphaltene aggregation and diffusion coefficient. • Conducted complex viscosity tests and microscopy observation of SBS-modified asphalt. • Evaluated compatibility and stability through interaction energy and gyration radius of SBS from simulation. Asphalt binder modified by styrene butadiene styrene (SBS) has been widely used for improving pavement quality. However, compatibility issues between asphalt and SBS remain for phase separation and storage stability. This study aims to investigate the compatibility between asphalt and SBS with different molecular structures. Coarse grained models for asphalt binder were built based on Dissipative Particle Dynamics (DPD) and validated based on the calculated interlayer distance and diffusion coefficient of asphaltenes. The interaction energy and gyration radius were used as performance indicators of compatibility from molecular simulation; while complex viscosity tests and fluorescence microscopy were conducted for experimental evaluation. The results show that asphaltenes would aggregate more in SBS-modified asphalt than in virgin asphalt. The addition of SBS reduces diffusion coefficients of aromatics, resins, and saturates, but not asphaltenes. The SBS with less styrene shows the stronger interaction energy and the larger gyration radius intersecting with asphalt matrix, thus improves compatibility and stability of SBS-modified asphalt. These findings are in good agreements with the viscosity results of Cole–Cole plots and the observed phase morphology of SBS-modified asphalt. The analysis findings provide fundamental understanding of the interaction mechanisms between SBS polymer and asphalt at molecular scale. [ABSTRACT FROM AUTHOR]

With the increasing environmental considerations and rising costs of construction materials, reclaimed asphalt pavement (RAP) has been frequently added into asphalt paving mixtures during pavement construction. Many studies have been conducted with regard to the study of reclaimed unmodified asphalt pavement, but the reclaimed SBS modified asphalt pavement is still unknown. In this study, the effects of RAP and rejuvenating agent on the performance were studied. The moisture susceptibility, rutting resistance, dynamic modulus, low temperature anti cracking performance and fatigue was tested. Furthermore, in order to better understand the effects of RAP and rejuvenating agent, the control asphalt mixture was measured using the same methods. The results indicated that the asphalt mixture incorporating reclaimed SBS modified asphalt pavement with better moisture susceptibility, rutting resistance, dynamic modulus, low temperature anti cracking performance and fatigue resistance was obtained by blending new SBS modified asphalt binder and rejuvenating agent. Thus, the rejuvenating agent will benefit the effort of preparing more sustainable asphalt pavement containing RAP. [ABSTRACT FROM AUTHOR]