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To analyze the impacts of composition-associated factors of high-viscosity asphalt mixtures and thermal aging on the cohesion and adhesion characteristics of high viscosity–modified asphalt (HVMA), neat asphalts (NAs), high-viscosity additives, and aggregates were selected, and several HVMAs were first prepared. Then, the prepared HVMAs were subject to contact angle testing, and their cohesion and adhesion behaviors and influencing factors were explored by multifactor orthogonal testing coupled with the surface free energy (SFE) concept. Further, the variations and influencing factors of cohesion and adhesion properties of relevant HVMAs under aging were analyzed in comparison with styrene-butadiene-styrene (SBS)-modified asphalts (SBSMAs) and NAs. Lastly, under aging, the change behaviors of microscopic phases of HVMAs were contrastively investigated using atomic force microscopy (AFM) testing, and the relationship between the microscopic phases and the cohesion and adhesion properties was illustrated. Results showed that NA type, high-viscosity additive dosage and type, and aggregate type notably influenced the cohesion and adhesion of HVMAs, and the high-viscosity additive dosage influenced their cohesion the most. Aging weakened the cohesion and adhesion of asphalts, and the HVMAs possessed the superior cohesion and adhesion at each aging period. Under aging, the NA type, aggregate type, and aging level remarkably affected the cohesion and adhesion of HVMAs, among which the NA type affected their cohesion most prominently. Besides, the aggregate type was the most influential variable on the adhesion of HVMAs whether the HVMAs were aged or not. AFM testing demonstrated that aging reduced the component of microscopic phase structures of HVMAs and the amount of their bee structures, and diminished the surface roughness Ra of asphalt binders; in contrast, aging did not alter the component of microstructural morphology of SBSMAs and NAs. The cohesion and adhesion indexes of HVMAs under aging obeyed the high Pearson correlation and the moderate linear correlation with the Ra index. [ABSTRACT FROM AUTHOR]

Interface properties between asphalt and aggregate intimately affect the service performance and long-term durability of asphalt pavement. This study seeks to explore the interfacial adhesion features of high-viscosity asphalt (HVA)-aggregate under water conditioning to provide the understanding for the moisture damage of HVA-aggregate interface and asphalt pavement. To this end, the HVA was initially suffered from different durations of water conditioning, and atomic force microscopy (AFM) test was employed to gather the microscopic phase structure and adhesion force of water-conditioned HVA and aggregate, to analyze the adhesion variations of HVA-aggregate interface. Further, molecular dynamics method was used to simulate the changing process and influencing mechanism of adhesion effect at the HVA-aggregate interface under water immersion. The findings indicated that with the increasing water immersion, Catana phase of HVAs vanished, and concave and convex structures appeared on the surface, along with pit groove dispersion phase structures. Longer immersion time resulted in augmented surface roughness of HVA and a more dispersed height distribution in the area domain, most notably during the initial stages of water immersion. Aging increased sensitivity to immersion duration in terms of surface roughness, mechanical properties and adhesion ability of HVAs. Water immersion had a diminishing effect on the mechanical properties of HVA at different aging degrees, although it increased the micro-mechanical modulus of HVAs and impaired the interface adhesion with aggregates. Under water immersion, the phase structure and mechanical properties of HVAs and the interface adhesion indexes all distinguished a prominent negative Pearson correlation (correlation coefficient |R| > 0.7000), and these factors were critical for HVA-aggregate interface adhesion, as alterations in surface phase structure and micro-mechanical traits of HVAs triggered variations in the HVA-aggregate interface adhesion. In addition, water content in the interface layer, simulation temperature and mineral anisotropy significantly affected the interfacial adhesion of HVA and aggregate in water environment. The introduction of water and the rise of temperature considerably weakened the interfacial adhesion effect of asphalt-aggregate system, and the interface adhesion failure occurred once the water layer thickness surpassed 5 Å. Comparatively, the HVA-calcite system demonstrated better interfacial adhesion competence than the HVA-α-quartz system, and the HVA-calcite {1 0 4} system showed the optimal interfacial adhesion. [Display omitted] • Water erosion altered surface phase morphology and micro structure of HVA. • Longer immersion duration resulted in faded adhesive force of HVA. • Thermal aging enhanced the susceptibility of micro-properties of HVA to immersion time. • Interfacial adhesion failure occurred when the water layer surpassed 5 Å. [ABSTRACT FROM AUTHOR]

In order to develop an environment-friendly asphalt rejuvenator, waste vegetable oil (WVO) was selected as the base oil. The composition of the rejuvenator was first designed based on the response surface methodology (RSM), and 16 groups of rejuvenator samples were obtained. Then, these samples were used to regenerate aged asphalt and 16 groups of rejuvenated asphalt samples were prepared. Afterward, the viscous, conventional, rheological, and fatigue resistance properties of these rejuvenated asphalts were measured and evaluated, and the optimal composition of rejuvenator was determined. Results show that the addition of WVO-based rejuvenator can reduce the viscosity and softening point of aged asphalt, increase its penetration and ductility, and restore the physical properties and viscosity of aged asphalt to that of original asphalt. With the addition of WVO-based rejuvenator, the high-temperature performance of aged asphalt gradually declined, but the rejuvenator with optimal composition can restore its high-temperature performance to the similar level as original asphalt. The addition of WVO-based rejuvenator can evidently improve the fatigue damage resistance and low-temperature cracking resistance of aged asphalt, achieving a good regeneration effect. The fitting equation based on RSM can achieve an accurate and reliable prediction on the viscous, conventional, rheological, and fatigue damage properties of rejuvenated asphalt. According to the results of model optimization, the optimal composition of WVO-based rejuvenator is recommended as WVO:Dibutyl phthalate (DBP):antiaging agent (AA) = 90:9:1. [ABSTRACT FROM AUTHOR]

To explore the macroproperties of biorecycled asphalt and the correlation between its components and macroproperties, the cooking-aged waste soybean oil was used as the base oil, along with mixing additives, to prepare the biorejuvenator, and a total of six biorejuvenators with different component ratios were first developed. Then, using these rejuvenators, six biorecycled asphalts were prepared and their chemical components and viscosity and a series of pavement properties were measured and evaluated. Finally, using the gray correlation theory, gray correlation analysis between macroproperties and four components was conducted for recycled asphalts. Results show that the addition of biorejuvenator can adjust the component distribution in the aged asphalt, and the components in the aged asphalt can be gradually restored to the original level, thus achieving the regeneration of aged asphalt. Biorejuvenator can restore the penetration, softening point, ductility, and viscosity of aged asphalt to the same level as original asphalt. Further, the biorejuvenator with appropriate composition can restore the rheological parameters such as G* , δ , Jnr , Nf , S , and m of aged asphalt to the level consistent with that of original asphalt. And it can significantly improve the low-temperature and fatigue properties of aged asphalt, while ensuring that the high-temperature performance of regenerated asphalt meets the specification requirements. Overall, the regeneration effects of R5 [base oil: dibutyl phthalate (DBP): antiaging agent: stabilizer=88∶10∶1∶1 ] and R6 (base oil: DBP: antiaging agent: stabilizer=90∶8∶1∶1) are optimal, which can guarantee that the pavement performance of recycled asphalt basically meets the requirements of original asphalt. The gray correlation analysis shows that the change of the four components of biorecycled asphalt will significantly affect its viscosity, high- and low-temperature performance, and fatigue behavior. The seven indexes of δ , softening point, penetration, m , viscosity, S , and Nf2.5 demonstrate a higher gray correlation with the four components of asphalt (all exceed 0.6), followed by ductility, Jnr0.1 , and Jnr3.2. However, G* correlates poorly with the four components of asphalt, whose gray correlation degree is not more than 0.4. [ABSTRACT FROM AUTHOR]

At present, the rationality and applicability of various high-temperature performance evaluation indexes for polymer-modified asphalts have not been comprehensively explored. This study aimed to fully explore their rationality and applicability. For this purpose, five asphalt binders including four representative polymer-modified asphalts and one neat asphalt (NA) were chosen, and many of their high-temperature performance indexes were first obtained by using a series of tests. Then the five corresponding asphalt mixtures were fabricated and their high-temperature performance indexes were also obtained by performing a wheel tracking test. On this basis, the high-temperature potential of asphalt binders was evaluated using the obtained indexes, and the correlation between the indexes of asphalt binders and their mixtures was analyzed via data processing software. Results show that the rankings of high-temperature performance of these five asphalt binders are not exactly consistent when all the high-temperature performance indexes—including penetration (P) at 25°C, penetration index (PI), equivalent softening point (T800), softening point (SP), dynamic viscosity (DV) at 60°C, rutting factor (G*/sinδ), improved rutting factor [G*/(sinδ)9] , Shenoy's nonrecoverable compliance (JShenoy), critical temperature of rutting factor (TG*/sinδ), nonrecoverable creep compliance (Jnr), creep modulus (GV), zero shear viscosity (ZSV), and generalized dynamic shear modulus (GDSM)—are utilized for evaluation. However, all the indexes can distinguish the polymer-modified asphalts from NA well. Among these indexes, the evaluation results of Jnr at different temperatures are consistent at the same stress level (0.1 or 3.2 kPa), and all the correlation coefficients between the Jnr and dynamic stability (DS) of asphalt mixtures exceed 0.9; thus, the Jnr is recommended as the dominant evaluation index. The G*/sinδ , TG*/sinδ , and GV correlate weakly with the DS, and the ZSV performs poor repeatability in the test; thus, their rationality needs to be further verified using more asphalt samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Variations of cohesion, adhesion and micro-attributes of asphalts under UV aging were explored. • Variation mechanism of asphalt-aggregate interface properties was illustrated. • UV aging degraded the cohesion and adhesion capacity of asphalt binders. • UV aging showed an enhanced impact on the interface features with the extended UV radiation time. • Adhesion force F ad most affected the interfacial cohesion and aqueous-condition adhesion. Time-dependent variation and mechanism of asphalt-aggregate interface features under ultraviolet (UV) aging have not yet been illustrated. This study explored the time-dependent variation and mechanism of asphalt-aggregate interface features under UV aging. To this end, six asphalt binders were chosen and subjected to different durations of UV aging, and then the variation behaviors of their cohesion-adhesion ability with the changing UV radiation time were analyzed through surface energy theory. Further, the microscopic attributes of asphalt binders experiencing the various UV aging durations were measured and their varying rules were investigated with a series of micro observations. Finally, the relationship between cohesion-adhesion characteristics and microscopic properties were illustrated and thus the variation mechanism of interfacial cohesion and adhesion were revealed by mathematical statistics and image presentation. The results showed that UV aging weakened the cohesion and multi-working adhesion of asphalt binders and the moisture stability of asphalt-aggregate systems, and overall presented a gradually strengthened influence on them with the prolonged UV radiation time, especially the UV radiation exceeded 6 days. The variation of phase morphology of asphalt binders under UV aging depended on the asphalt types and neat asphalt oil sources, and there existed a favorable linear relationship between Catana phase of asphalt binders and surface roughness. Adhesion force, function group and four components (saturate (S), aromatics (Ar), resin (R) and asphaltene (As)) also exhibited a gradually increasing variation as the UV radiation duration went on, and among which, the UV aging reduced the adhesion force of asphalt binders. Adhesion force F ad demonstrated the highest Pearson relevance with the cohesion and aqueous-condition adhesion and the moisture stability of asphalt-aggregate system, and the cohesion-adhesion properties of asphalt binders under UV aging met the multivariate linear mathematical relationship with the microscopic attributes screened, with the goodness-of-fit greater than 0.7000. [ABSTRACT FROM AUTHOR]

• Thermal aging behavior of HVA was contrastively explored from cohesion, adhesion and rheology perspectives. • Variations of phase topography and functional groups of HVA under aging were investigated using AFM and FTIR tests. • Correlation between macro-micro indicators of asphalts under aging was analyzed according to grey correlation theory. • Aging weakened cohesion, adhesion and low-temperature property of HVA and diminished its surface roughness. • Surface roughness R a and functional group indexes correlated well with several macro indexes. High viscosity asphalt (HVA) has been widely utilized in the paving of large-void asphalt pavement, and it will be affected by thermal aging and exhibit different pavement performance. In this study, through a series of macroscopic and microscopic experiments, the change behaviors of cohesion, adhesion, high- and low-temperature rheological properties, microscopic phase structure and functional groups of HVA under different thermal aging conditions were first analyzed—in comparison with the three asphalts viz. styrene-butadienestyrene (SBS) modified asphalt (SBSMA), crumb rubber modified asphalt (CRMA) and neat asphalt (NA). Further, the relationship between macro-micro properties of asphalt binders was investigated by grey correlation theory, and the comprehensive performance of HVA at different aging stages and its aging resistance were contrastively evaluated via using radar chart analysis method. Results showed that aging degraded the cohesion and adhesion of asphalt binders as well as the water stability of asphalt-aggregate systems, and weakened the low-temperature property of asphalt binders—compared to the unaged sample, the short- and long-term aging reduced the cohesion work of HVA by 1.10% and 3.41%, respectively, and decreased the water stability index of HVA-limestone system by 0.54% and 1.86%, respectively. However, the variations of viscoelastic properties, temperature sensitivity, creep recovery ability and rutting resistance of HVA under aging were inconsistent with those of SBSMA, CRMA and NA. Aging decreased the microscopic surface roughness R a of HVA and altered the intensity of functional groups at different wavenumbers, and the short- and long-term aging diminished its R a by 21.26% and 37.85% compared to the unaged sample, respectively. Grey correlation analysis showed that the microscopic surface roughness R a and the functional group indexes at different wavenumbers correlated well with several macroscopic indexes, which successfully explicated the variations of macroscopic properties of HVA from the micro perspective. Radar chart analysis displayed that the comprehensive performance of HVA in the original and short-term aging stages was second only to CRMA, but its comprehensive performance after long-term aging was only superior to NA; overall, HVA exhibited the most favorable anti-aging performance. [ABSTRACT FROM AUTHOR]

• WESE slurry seal used as the under-seal coat for rigid pavement was designed. • Anti-erosion, bonding and isolation properties of WESE slurry seal were evaluated. • Fine-graded WESE slurry mixture with 13.5% WESE has a higher performance-cost ratio. • WESE slurry seal shows a superior anti-erosion property and bonding with semi-rigid base. • Fine-graded WESE slurry seal demonstrates a most excellent isolation effect. Common slurry seal is poor at preventing pumping distress when used as the under-seal coat in rigid pavement. In order to improve the water stability of common slurry seal and reduce the pumping distress in rigid pavement, this paper adopts the method of compositely modified slurry seal using waterborne epoxy resin (WER) and styrene-butadiene rubber (SBR) latex. First, waterborne epoxy-SBR asphalt emulsion (WESE) was prepared and fine-graded WESE slurry seal was designed according to the performance requirements for the under-seal coat in rigid pavement. Then, dynamic water erosion resistance, bonding performance and isolation effect of the WESE slurry seal was analyzed and evaluated via a series of tests. Results showed that the water content, the dosage of WER in the WESE, and the WESE content had an effect on the properties of the WESE slurry mixture. In terms of the fine-graded WESE slurry mixture, the content of water and WESE is recommended to be 8.5% and 13.5%, respectively, by weight of aggregate, and the dosage of WER is recommended to be 3% by weight of WESE. The WESE slurry mixture, especially the fine-graded WESE slurry mixture, showed excellent resistance to dynamic water erosion. Moreover, the bonding performance between the WESE slurry seal and the semi-rigid base was affected by seal gradation, forming temperature and curing temperature. In order to guarantee a good bonding performance, the WESE slurry seal should be designed as a fine-graded mineral aggregate, and it should be formed at 20 °C and cured at no less than 10 °C. The WESE slurry seal showed the best isolation effect compared to both the chip seal and the asphalt concrete seal. [ABSTRACT FROM AUTHOR]

Neat asphalt emulsions have poor physicochemical properties. In order to endow neat asphalt emulsions with excellent physicochemical properties and broaden their application as pavement, this study adopted the composite modification method using waterborne epoxy resin (WER) and styrene–butadiene rubber (SBR) latex. Firstly, a waterborne-epoxy–SBR composite modified asphalt emulsions (WESAEs) with different amounts of WER were prepared, and the storage stability, workability, and residual properties were characterized with a series of tests. Then, the performance of the WESAEs was comprehensively evaluated by multiobjective gray target decision-making method, through which the optimal amount of WER in WESAE was determined. Lastly, the modification mechanism of WER was revealed by Fourier-transform infrared spectroscopy test. The results show that the incorporation of WER improves the high-temperature performance, thermal stability, rheological property, and adhesion of the SBR modified asphalt emulsion (SBRAE) residues. However, an excessive amount of WER will adversely affect the storage stability, particle distribution uniformity, and workability of the WESAE binder. The WESAE with 3% WER showed the best comprehensive performance; thus, the optimal amount of WER is 3% of the weight of the WESAE. Additionally, modification of the SBRAE by WER is a physical blending process, meaning no chemical reaction occurs in the blending process. [ABSTRACT FROM AUTHOR]

• Bio-rejuvenators include wood fiber, animal manure and waste oil types. • Bio-rejuvenator improves cracking resistance and moisture resistance. • Bio-rejuvenator reduces high temperature performance of aged asphalt. • Bio-rejuvenator restores the composition and performance of aged asphalt. To make full use of massive waste asphalt materials produced in the road construction and maintenance, and to solve the problems of low efficiency and poor environmental protection of petroleum-based rejuvenators, bio-rejuvenator was proposed to regenerate the waste asphalt materials. The bio-rejuvenator is a green, environmental protection and renewable material, which has a very wide application prospect in the regeneration. For the purpose of promoting the later research and application of bio-rejuvenator, this review summarizes the research progress of bio- rejuvenator in the regeneration of waste asphalt materials. The review results show that the bio-rejuvenator can significantly improve the low-temperature performance of waste asphalt binder, and restore its high-temperature performance to the level consistent with the virgin asphalt. Moreover, the bio-rejuvenator of waste oil type is studied most at present, and its optimum dosage is kept within about 18%, followed by wood fiber type, with a recommended optimum dosage of 5% ~ 20%. There are relatively few studies regarding animal manure type-rejuvenator, and the optimal dosage of swine manure-based bio-rejuvenator is approximately 5% ~ 10%. The addition of bio-rejuvenators can restore the chemical composition and pavement performance of aged asphalt, and achieve its regeneration. Among them, these four bio-rejuvenators of waste soybean oil (WSO), tung oil (TO), waste vegetable oil (WVO) and waste cooking oil (WCO) can significantly decrease the functional group index of aged asphalt, and WCO and 9% waste pig fat (WPF) can restore the four component content distribution of aged asphalt to the same level as virgin asphalt. Furthermore, the bio-rejuvenated asphalt mixture possesses good low-temperature crack resistance, moisture resistance and fatigue crack resistance; moreover, an appropriate amount of bio-rejuvenator can restore the high-temperature stability of the old asphalt mixture to the same level as that of fresh asphalt mixture. Future researches should be executed from the following aspects: further explore how to raise the utilization rate of waste asphalt material meanwhile guaranteeing the sufficient performance of bio-rejuvenated mixture; further explore the regeneration mechanism of bio-rejuvenator on aged asphalt from the micro- even nano-scale as well as the regeneration effect of bio-rejuvenators from other biomass sources; investigate its application in warm-mixed rejuvenated asphalt mixture while focusing on the regeneration of hot-mixed asphalt mixture by bio-rejuvenator; further research regarding fatigue property of rejuvenated asphalt mixture should be conducted and fatigue life prediction model should be also investigated; forming a unifying technical specification for bio-regeneration technology to standardize its application in the regeneration of waste asphalt materials. [ABSTRACT FROM AUTHOR]

• The HVM asphalt mixture composed by SBS compound modified asphalt has advantages in construction workability and comprehensive properties. • Construction workability of HVM asphalt mixture is significantly affected by the asphalt type and mixing temperature, and the latter influences more significantly. • The high viscosity modifier can be replaced with the self-developed HVM asphalt with SBS compound modifier to prepare SMA mixture of steel deck pavement. To seek the optimum asphalt binder used in stone mastic asphalt (SMA) mixture of steel deck pavement, the common modified asphalt in the SMA-13 mixture was replaced with high viscosity modified (HVM) asphalt, and the four kinds of HVM asphalts were selected in this paper. The different test methods such as experimental device of mixing power at different velocities, rutting test, Hamburg wheel tracking device(HWTD) test, bending test at low temperature and indirect tensile fatigue test were conducted to evaluate the construction workability, temperature stability, water stability and fatigue performance of HVM asphalt mixture. Besides the performance difference of various HVM asphalt mixture was also discussed. The results show that construction workability of SMA-13 mixture is significantly affected by the asphalt type and mixing temperature, and the influence of mixing temperature on construction workability is more obvious. Besides it is proved that the construction workability of asphalt mixture is influenced by asphalt viscosity and mineral aggregate. The SMA mixture with self-developed HVM asphalt composed by the linear and star styrene-butadienestyrene block copolymer (SBS) modifier has advantages in construction workability and comprehensive properties. Thus the above asphalt can be selected to prepare SMA mixture applied in steel deck pavement. The construction workability, high temperature performance and fatigue performance of HVM asphalt mixture with SBS compound modified asphalt are close to HVM asphalt mixture with TPS additive or HVM asphalt mixture with SINOTPS, and the the former low temperature performance and water stability are superior to HVM asphalt mixture with TPS additive and HVM asphalt mixture with SINOTPS. The dosage of SBS compound modifier in HVM asphalt is just 6.0%, and the blending ratio of linear SBS modifier and star SBS modifier in the compound modifier is 2:1. It means that the self-developed HVM asphalt with SBS compound modifier has the high performance-price ratio. The reduction of key modified materials in HVM asphalt will be conducive to saving the construction cost of pavement, which will promote the HVM asphalt with SBS compound modifier applying in SMA mixture of steel deck pavement. [ABSTRACT FROM AUTHOR]

• A new warm-mix recycling agent was developed using uniform design method. • WR improves low-temperature property and fatigue resistance of reclaimed asphalt. • WR remarkably reduces construction temperatures of reclaimed asphalt. • Compared with commercial rejuvenators, WR exhibits better economical benefit. Warm-mix recycling asphalt mixture has remarkable environmental and economic benefits. In this study, a new warm-mix recycling agent (WR) was developed by using base oil (80%), surfactant (9.5%), plasticizer (8.0%) and antiaging agent (2.5%) based on uniform design method. Experimental tests including penetration, softening point, ductility, elastic recovery, dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), bending beam rheometer (BBR), linear amplitude sweep (LAS), rotational viscosity as well as Fourier transform infrared spectroscopy (FTIR) test were conducted to evaluate the properties of aged binders incorporating the WR and other two commercial rejuvenators, i.e. an emulsified rejuvenator (ER) and a resinous rejuvenator (RR). Additionally, the workability and cost of reclaimed asphalt binders were analyzed. Results indicate that the WR is able to rejuvenate conventional physical properties of aged asphalt. Reclaimed asphalt containing WR shows the best low-temperature performance and longest fatigue life than that containing other two commercial rejuvenators. With regard to high-temperature performance, reclaimed asphalt incorporating WR compares favorably with that incorporating ER. The results from FTIR test demonstrated that physical interaction dominated the rejuvenation of aged asphalt after adding the WR. WR can significantly replenish the volatiles in aged asphalt, and restore its components' proportion that resembles the virgin asphalt. In comparison with ER and RR, WR exhibits a lower increased cost and the excellent capability of reducing mixing and compaction temperature. [ABSTRACT FROM AUTHOR]