Functional Group Indices Research Articles

Utilization of thermoplastic resin as foamed asphalt modifier in cold recycled mixtures

The utilization of foamed virgin asphalt in cold recycled mixtures results in insufficient bonding strength between aggregates, leading to rapid deterioration to the recycled asphalt pavement. This ultimately causes inefficient clean production and increased carbon emissions. The foaming performance of thermoplastic resin modified asphalt (TRA) under different foaming conditions was analyzed. Micro-scale chemical and physical tests were utilized to discover the foaming mechanism of TRA. The road performance of cold recycled mixtures with foamed TRA was evaluated through splitting, rutting and fatigue tests. The results showed that the increase in the TRA polar functional group index led to an increase in its surface tension, thus limiting its expansion capacity. However, the increase in the specific heat capacity of TRA indicated that it preserves a low viscosity level essential for its foaming efficacy post-ejection from the foaming machine, thereby enhancing its half-life. Furthermore, the dynamic viscosity of the TRA with an 8% thermoplastic resin dosage exceeded 40000 Pa s at 60 °C, meeting the specification requirements for high viscosity asphalt, while exhibiting a notably lower viscosity of only 120 mPa s at the foaming temperature of 170 °C. The observed low viscosity of the asphalt is anticipated to favorably enhance the formation of a stable foam structure. The mechanical properties and overall road performance of the cold recycled mixture with foamed TRA were significantly enhanced, especially in terms of moisture damage resistance and low-temperature crack resistance. The purpose of this paper is to serve as a valuable reference for investigating the mechanism of modified asphalt foaming and to enhance the efficiency of cold recycled pavement regeneration processes.

Enhanced degradation of phototreated recycled and unused low-density polyethylene films by Pleurotus ostreatus.

Polyethylene, one of the most used petroleum-derived polymers, causes serious environmental pollution. The ability of Pleurotus ostreatus to degrade UV-treated and untreated recycled and unused (new) low-density polyethylene (LDPE) films was studied. We determined the fungal biomass production, enzyme production, and enzyme yield. Changes in the chemical structure and surface morphology of the LDPE after fungal growth were analyzed using FTIR spectroscopy and SEM. Functional group indices and contact angles were also evaluated. In general, the highest Lac (6013 U/L), LiP (2432 U/L), MnP (995 U/L) and UP (6671 U/L) activities were observed in irradiated recycled LDPE (IrRPE). The contact angle of all samples was negatively correlated with fermentation time; the smaller the contact angle, the longer the fermentation time, indicating effective biodegradation. The IrRPE samples exhibited the smallest contact angle (49°) at 4 weeks, and the samples were fragmented (into two pieces) at 5 weeks. This fungus could degrade unused (new) LDPE significantly within 6 weeks. The biodegradation of LDPE proceeded faster in recycled than in unused samples, which can be enhanced by exposing LDPE to UV radiation. Enzymatic production during fungal growth suggest that LDPE degradation is initiated by laccase (Lac) followed by lignin peroxidase (LiP), whereas manganese peroxidase (MnP) and unspecific peroxygenase (UP) are involved in the final degradation process. This is the first experimental study on the fungal growth and its main enzymes involved in LDPE biodegradation. This fungus has great promise as a safe, efficient, and environmentally friendly organism capable of degrading LDPE.

From crude oil to bitumen: Genetic variability in chemistry and its influence on viscoelastic of binders

The chemical composition and properties of bitumen are derived from crude oil, which directly influences its viscoelastic properties. Six different crude oil sources were examined to explore how crude oil characteristics impact bitumen. The bitumen was produced through in-house atmospheric decompression distillation, and aging tests were conducted on these samples. The chemical properties of the crude oils, virgin binders, and aged binders were analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Additionally, the separation and quantitative analysis of saturates, aromatics, resins, and asphaltenes (SARA) in crude oil and bitumen binders were carried out using Thin Layer Chromatography-Flame Ionization Detector (TLC-FID). Sweep tests on binders were conducted using a Dynamic Shear Rheometer (DSR). Master curves were created based on the CAM model and the 2S2P1D model to assess the dynamic viscoelastic properties of bitumen. The grey correlation method was employed to examine how bitumen chemical composition and properties affect its viscoelasticity. Results indicated that crude oil profoundly influences bitumen's chemical composition and properties. The functional group index and component content of bitumen are inherited from crude oil and are closely linked to the corresponding indices of crude oil. The functional group index, SARA, and colloidal stability coefficients of bitumen are intimately connected to the viscoelastic parameters of bitumen. The impact of the functional group index on the viscoelastic parameters is more pronounced than that of SARA content. This insight is crucial for guiding the selection of oil sources in bitumen production processes.

Synthesis of a new Schiff base acceptor–donor molecule as a UV stabilizer for enhanced poly(lactic acid) (PLA) photoprotection

AbstractPoly(lactic acid) (PLA) is a biodegradable aliphatic polyester of significant interest. Owing to its traits, PLA stands out as one of the most widely used polymers in various fields. Nevertheless, environmental conditions, such as heat, UV light, and humidity have negative impacts on the polymer's performance as a result of the accelerating aging process. In this study, we present a novel acceptor–donor (AD) Schiff base molecule that demonstrates significant UV stabilization when incorporated into the polymer's matrix. The stabilization effect of the AD molecule was studied by using the weight loss method and tracking the functional group indices of CO (ICO) and OH (IOH) that emerge because of polymer degradation after irradiation with UV light for 300 h. The films' structures were studied by scanning electronic microscopy (SEM), atomic force microscope (AFM), and energy‐dispersive x‐ray spectroscopy (EDX) to evaluate the stabilization enhancement of AD moiety. The results exhibit a significant decrease in weight loss for blended PLA, in contrast to blank PLA. The weight loss percentage reduced from 2.5 for blank PLA to less than 0.7 for blended PLA. Furthermore, ICO and IOH indices witness a remarkable reduction which verifies the improved photodegradation resulting from AD moiety. The suggested method involves the efficient absorption of UV radiation produced during photo‐degradation by the AD molecule, which then emits this light as visible blue light without causing any damage to PLA film's chemical structure. Our results demonstrate the adaptability of AD molecules as PLA photo‐stabilizers and point to their wider significance for sustainable material applications. This work advances the stability of PLA films and provides opportunities for the creation of novel stabilization techniques based on organic electrical principles. Future studies may examine the multipurpose uses of the AD molecule in sensor materials and other contexts.Highlights Presenting a novel acceptor–donor Schiff base as a phot stabilizer of PLA. Using the weight loss method and tracking the functional group indices to test the degradation. A significant decrease in weight loss for blended PLA, in contrast to blank PLA. The Schiff base absorbing UV light, excited electrons from ground state to excited state. They return to the ground state and produce bright blue light. These movement of electrons cause no damage to the PLA polymer chains.

Macro-micro correlation analysis of rheological characteristics for composite modified asphalt

Purpose This study aims to investigate the micro mechanism of macro rheological characteristics for composite modified asphalt.Grey relational analysis (GRA) was used to analyze the correlation between macro rheological indexes and micro infrared spectroscopy indexes. Design/methodology/approach First, a dynamic shear rheometer and a bending beam rheometer were used to obtain the evaluation indexes of high- and low-temperature rheological characteristics for asphalt (virgin, SBS/styrene butadiene rubber [SBR], SBS/rubber and SBR/rubber) respectively, and its variation rules were analyzed. Subsequently, the infrared spectroscopy test was used to obtain the micro rheological characteristics of asphalt, which were qualitatively and quantitatively analyzed, and its variation rules were analyzed. Finally, with the help of GRA, the macro-micro evaluation indexes were correlated, and the improvement efficiency of composite modifiers on asphalt was explored from rheological characteristics. Findings It was found that the deformation resistance and aging resistance of SBS/rubber composite modified asphalt are relatively good, and the modification effect of composite modifier and virgin asphalt is realized through physical combination, and the rheological characteristics change with the accumulation of functional groups. The correlation between macro rutting factor and micro functional group index is high, and the relationship between macro Burgers model parameters and micro functional group index is also close. Originality/value Results reveal the basic principle of inherent-improved synergistic effect for composite modifiers on asphalt and provide a theoretical basis for improving the composite modified asphalt.

The production of bacterial cellulose from coconut water and its application as a green photocatalyst composite membrane

AbstractIn this research work, bacterial cellulose was produced from the fermentation of coconut water and incubated for 4, 5, and 6 days. The bacterial cellulose membrane was utilized as immobilized silver nanoparticles (AgNPs). A green photocatalyst membrane was prepared by reducing silver ions in the bacterial cellulose matrix structure using local fruit extracts, tomatoes, Citrus hystrix fruit, and mangosteen peel as a reducing agent. The composite was dried in the oven to obtain a more durable fixed structure. The properties of produced bacterial cellulose were determined by measuring the thickness, water retention capacity (WRC), cellulose content, and swelling. The functional group and crystallinity index of bacterial cellulose were observed by FTIR and XRD instrument analysis. The SEM EDX analysis confirms that the silver ions were successfully reduced in the BC matrix, and the UV–Vis spectrum showed that the composite membrane has the ability to degrade the methylene blue solution under sunlight irradiation. The maximum degradation efficiency of the composite membrane against 5 ppm methylene blue solution was achieved by the composite membrane reduced by tomatoes, with a value of 93%. This result proved that the composite membrane produced in this research has excellent capabilities as a green photocatalyst for degrading wastewater containing dye pollutants.

Properties deterioration of recovered bitumen under coupling multi-environment factors based on the ageing simulation device

The properties of pavement bitumen deteriorates when exposed to complicated environmental factors. This study developed a multi-environment simulation device to apply multi-factor coupling on asphalt mixtures. The physicochemical properties of recovered bitumen were analysed by traditional technical indicators, tensile strength, fourier transform infrared spectroscopy, and contact angle tests. The ageing index and target functional group index ratio were proposed to quantify the interactions of environmental factors. The results indicated that surface morphology of mixtures was severely affected by multi-factor coupling. The multi-factor coupling exacerbated the deterioration of physical properties and increased tensile strength, surface free energy, and adhesion work. However, the sulfoxide index was more affected by thermal ageing than the carbonyl index, and its change under ultraviolet and multi-factor actions was not obvious. The ageing index and target functional group index ratio indicated that the effect of ultraviolet-thermal coupling had the largest effect on the physicochemical properties of bitumen.

UV-induced gradient aging of bitumen films: A comprehensive study

The aging of bitumen materials under ultraviolet (UV) radiation is a highly intricate process involving volatilization of components and multiple photochemical reactions. To gain a comprehensive understanding of the mechanism and progression of UV aging in bitumen films within bitumen mixtures, this study investigates the formation and evolution of UV aging gradients in bitumen films from various perspectives, including morphology, composition, macro-, and micro-mechanical aspects. Initially, specific bitumen film specimens were subjected to aging, and a protocol for sample handing and testing was developed. Optical microscopy images, functional group indices, and component contents of the bitumen films were then measured and calculated to track the UV aging process from the surface to the interior. Additionally, profiling micro-mechanical tests and layer-by-layer dynamic mechanical tests were conducted to characterize the variations in mechanical properties induced by UV aging gradients within the bitumen films. The results indicate that UV radiation causes significant volatilization of light components on the film surface, resulting in wrinkling. Concurrently, photochromic reactions take place in both bitumen macromolecules (asphaltenes and resins) and small molecules (saturates and aromatic), while molecular photodegradation may also occur. Fluorescence imaging, infrared spectroscopy analysis, and component determination reveal that the degree of UV aging in the bitumen films increases with radiation time and gradually propagates towards the interior. C-S bonds are more sensitive to UV radiation than C = C bonds, leading to oxidation and the formation of sulfoxide groups. Due to the adsorption of light components by aggregates, the modulus values at the surface of aged bitumen films and the aggregate interface are higher, while the intermediate region exhibits lower values. Rheological indicators demonstrate that UV aging, to a certain extent, results in the decomposition of bitumen molecules, leading to a decrease in complex shear modulus and an increase in phase angle. This work significantly enhances our understanding of the mechanism of UV aging in bitumen films and holds important implications for the design and development of UV-blocking materials.

Deterioration mechanism of adhesion property for SBS modified asphalt in salt-freeze-thawing environment

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.

Physical and chemical evaluation of adhesion recovery property of aged high-viscosity asphalt based on specialized composite rejuvenators

With the wide application of porous asphalt pavement, the techniques for recycling aged porous asphalt mixture have attracted more attention for facilitating its sustainable development. One of the most critical issues is how to recover the adhesion properties of aged high-viscosity asphalt (HVA). In this study, different specialized composite rejuvenators types on the adhesive properties of aged asphalt binder were designed and evaluated for the goal of adhesion recovery. A bond strength test was used to evaluate the macroscale adhesion properties between the regenerated asphalt and aggregate. Micro-scale chemical and physical tests were utilized to discover the regeneration mechanism of specialized composite rejuvenators on asphalt adhesion. The results showed that the proposed three kinds of composite rejuvenators can effectively restore and improve the adhesive properties of aged HVA. The results of differential scanning calorimetry (DSC) represented that recycled HVA with smaller Tg and total heat absorption showed better adhesion properties. The FT-IR and AFM test results showed that the adhesion of recycled HVA is highly correlated with the C–O functional group index and micro adhesion. In addition, the concave structure in the asphalt surface is more beneficial to improve the asphalt-aggregate interface bonding, and the scheme of adding 8% optimized rejuvenator based on graft co-polymerization had the best effect, which could be promoted for the future application in the recycling of HVA in porous asphalt pavement.

Evaluation of anti-ageing performance of bitumen based on rheological and chemical characterisation

ABSTRACT Improving the anti-ageing performance of bitumen plays a vital role in prolonging the service life of bituminous pavement. A bituminous additive for resisting all-weather ageing (BARAA), with excellent anti-ageing performance and fewer side effects, was developed in this study. The service life of bitumen can be doubled by using BARAA. The results show that the anti-ageing index and influence index can quantitatively evaluate the anti-ageing performance of anti-ageing additives. The BARAA was composed of amine antioxidant (1.89% by weight of base bitumen), Ni-containing antioxidant (3%) and hindered amine light stabilisers (0.7%). BARAA effectively delayed the deterioration of bitumen performance during ageing. The J nr reduction of BARAA-modified bitumen caused by ageing was 17.7% of the base bitumen. At −12°C and −18°C, the S increase of BARAA-modified bitumen caused by ageing was about 35% of the base bitumen. The oxidation during ageing was inhibited. The growth of sulphoxide groups can be curbed by BARAA. After long-term ageng, the aromatic ring increase of BARAA-modified bitumen was 41.1% of the base bitumen. In addition, the increase of average molecular weight and functional group index of BARAA-modified bitumen caused by long-term ageing was 57% and 19.1% of the base bitumen, respectively.

Analysis and Prediction Model of Styrene-Butadiene-Styrene-Modified Asphalt Aging by Infrared Spectroscopy

Thermal-photo-oxidative coupling and anaerobic and thermal-oxidative aging conditioning at 135°C were conducted on styrene-butadiene-styrene (SBS)-modified asphalt at different aging temperatures in this paper. The changes of the functional group index before and after aging of modified asphalt were quantified by the attenuated total reflection method of Fourier transform infrared spectroscopy, and a nonlinear model of aging degree and aging prediction of SBS-modified asphalt was established. The results show that the comprehensive aging index, which characterizes the aging of SBS-modified asphalt by the carbonyl index, sulfoxide index, polybutadiene index, and polystyrene index, can evaluate the aging degree well. The established nonlinear model can accurately quantify the final aging degree and aging rate of SBS-modified asphalt.

Modification of poly(vinyl chloride) by mefenamic acid in presence of micro metallic oxides as self photostabilizer

To date, many approaches have been made to stabilize the chemical structure of PVC when exposed to sunlight in outdoor usage. This work includes utilizing mefenamic acid (1 % per polymer weight) as a new photo stabilizer unit to adjust PVC to enhance resistance to change under UV exposure. Modification by attaching a new unit that contains an aromatic substance could protect the polymer from UV light due to its ability to absorb it. Positive results were obtained, as the interaction between mefenamic acid and PVC succeeded, using the FTIR technique to characterize the chemical structure of the product. FTIR spectrum of modified PVC shows the disappearance of (OH) band in the region above 3200 cm−1 which is clear evidence that the connection between the polymer and mefenamic acid has happened through the OH group. In addition, we have investigated the influence of microparticle metallic oxides such as TiO2, and Cr2O3, using only 1 % per modified polymer weight, on the photodegradation process of PVC materials. Several approaches have been utilized to investigate the photo-stability of studied materials which are FTIR functional group indices, weight-loss percentage, microscopic images, SEM, and AFM. They demonstrated that modified PVC gives better stability after exposure to UV in comparison to unmodified PVC. It's interesting to note that adding titanium dioxide to modified PVC has increased the amount of UV protection by acting as a UV shielding agent and blocking the light's path to the polymer. Thus, chromium oxide has demonstrated the opposite findings because it functions as a photo-catalytic reagent that accelerated the photo-degradation process. This result may be interpreted as the decomposition of waste PVC, which poses a major threat to the marine ecosystem.

Thermal oxidative aging mechanism of lignin modified bitumen

Lignin is the most abundant renewable resource in nature, which can be applied to not only improve resource utilization but also improve bitumen road performance. In this study, the evolution of lignin during thermal-oxidative aging of bitumen was investigated by dynamic shear rheology test (DSR), thermogravimetric test (TG) and Fourier transform infrared spectroscopy (FTIR). The thermo-oxidative aging mechanism of lignin modified bitumen was analyzed. The results show that lignin-modified bitumen had better aging resistance than the virgin bitumen. Meanwhile, the changes of functional group indices at 1460 cm−1, 1512 cm−1, and 1600 cm−1 in the infrared spectra proved that the thermal-oxidative aging mechanism was the decomposition of lignin itself under the action of thermal oxygen, which inhibited the aging process of bitumen.

Rheological Behaviors and Damage Mechanism of Asphalt Binder under the Erosion of Dynamic Pore Water Pressure Environment.

Asphalt binder plays an important role in the overall resistance of asphalt mixture to the moisture damage induced by a dynamic pore water pressure environment. This study evaluates the moisture sensitivity of asphalt binder from the perspective of rheological behaviors using the dynamic shear rheometer (DSR) and the bending beam rheometer (BBR) methods at high, medium, and low temperatures. The damage mechanism is further discussed quantitatively based on the Fourier transform infrared spectroscopy (FTIR) method. The results indicate that a longer conditioning duration is beneficial for asphalt binder to recover its adhesion at 60 °C in multiple stress creep recover (MSCR) tests, but the increasing pore water pressure magnitude of 60 psi held an opposite effect in this study. The asphalt binder's fatigue life at 20 °C in linear amplitude sweep (LAS) tests decreased obviously with conditioning duration and environmental severity, but the reducing rate gradually slowed down, while the groups of 50 psi-4000 cycles and 60 psi-4000 cycles held a comparable erosion effect. Both the stiffness and relaxation moduli at -12 °C in the BBR tests exhibited an obvious decreasing trend with conditioning duration and environmental severity. The erosion effect on the asphalt binder was gradually enhanced, but it also exhibited a slightly more viscous performance. Water conditioning induced several obvious characteristic peaks in the FTIR absorbance spectra of the asphalt binder. The functional group indexes presented a trend of non-monotonic change with conditioning duration and environmental severity, which made the asphalt binder show complicated rheological behaviors, such as non-monotonic variations in performance and the abnormal improving effect induced by dynamic pore water pressure conditioning.

Effect of Thermal-Oxygen Aging on Temperature Stability of Styrene-Butadiene-Styrene–Modified Asphalt

Abstract In order to explore the effect of aging on the temperature stability of styrene-butadiene-styrene (SBS)-modified asphalt, matrix asphalt and SBS-modified asphalt were used as the control to conduct short-term aging and long-term aging. Three indexes of asphalt with different aging degrees were tested to analyze the change rule of each index. The specific heat capacity and phase transition temperature of SBS-modified asphalt before and after aging were studied by differential scanning calorimetry (DSC). At last, the mechanism was studied by attenuated total reflection Fourier infrared spectroscopy. The results show that the penetration and ductility of matrix asphalt and SBS-modified asphalt decrease with the deepening of aging. The difference is that the softening point of matrix asphalt shows an increasing trend, whereas the softening point of SBS-modified asphalt shows a changing rule of first decreasing and then rising. The addition of SBS modifier can increase the specific heat capacity of asphalt and change the viscosity-flow conversion temperature. The degradation of SBS modifier leads to the decrease of the specific heat capacity after long-term aging, whereas the viscosity-flow conversion temperature decreases first and then rises, which is consistent with the change law of softening point. As a special block copolymer, the specific heat capacity of SBS modifier is determined by the polymer butadiene with lower glass transition temperature, whereas the softening point changes with the polymer styrene with higher glass transition temperature, which is consistent with the change rule of functional group index, softening point, and specific heat capacity of SBS-modified asphalt before and after aging.

Interaction of nanoplastics with simulated biological fluids and their effect on the biofilm formation.

Over the last decade, it has become clear that the pollution by plastic debris presents global societal, environmental, and human health challenges. Moreover, humans are exposed to plastic particles in daily life and very limited information is available concerning human health, especially interactions with biological fluids. Therefore, the aim of this study is to investigate the interaction of plastic particles with simulated biological fluids (e.g., artificial saliva, artificial lysosomal fluid, phagolysosomal simulant fluid, and Gamble's solution) using various exposure stages (2h to 80h) and the effect of plastic particles on the formation of Staphylococcus aureus biofilms under simulated biological conditions. The plastic particles incubating various simulated biological fluids were characterized using surface functional groups, zeta potentials, and elemental composition. The results indicated that functional group indices (C-O, C = O, C-H, C = C, C-N, S = O, and OH) decreased compared to the control group during the incubation periods, except for the hydroxyl group index. The FTIR results showed that the hydroxyl group formed with the artificial lysosomal fluid, the phagolysosomal simulant fluid, and Gamble's solution. With the impact of the declining functional groups, the zeta potentials were more negative than in the control. Moreover, EDX results showed the release of the components in the particles with the interaction of simulated biological fluids as well as new components like P and Ca introduced to the particles. The biofilms were formed in the presence of nanoplastic particles under both controlled conditions and simulated biological conditions. The amount of biofilm formation was mainly affected by the surface characteristics under simulated biological conditions. In addition, the biofilm characteristics were influenced by the O/C and N/C ratios of the plastic particles with the impact of simulated biological fluids.

Aging Analysis of Thermally Aged Asphalt Using Peak-Fitting Method: Its Pattern and Statistical Prediction

In this study, the peak fitting method was proposed to deal with and analyze the thermally aged pattern and statistical prediction of asphalt in order to reduce the calculation accuracy caused by overlapping and partial overlapping of infrared spectrum peaks. The aromatic functional group index, aliphatic branch chain index, aliphatic functional group index, butadiene functional group index, styrene index and carbonyl functional group index were used to evaluate the aged asphalt. The piecewise fitting method of OriginPro 9.0 was proposed to investigate the thermally aged pattern of asphalt based on the peak fitting method. From the testing results, after the process of thermal aging, the aromatic functional group index and carbonyl functional group index increased, the aliphatic branch chain index, aliphatic functional group index and butadiene functional group index decreased, and the styrene index was stable. Taking the carbonyl functional group index as the research object, the thermally aged pattern of asphalt based on the peak fitting method conformed to the two-reaction kinetic model and the aging process consists of a fast-rate reaction period and constant-rate reaction period, where the coefficients of determination are all above 0.91. These results show that the pattern and statistical prediction of thermally aged asphalt by infrared spectrum illustrate rapidly for a time and then develop at a relatively constant speed, which corresponds to the road performance of asphalt aging. Therefore, the aging condition of asphalt can be evaluated, which has important theoretical significance to predict the aging state of asphalt and accurately grasping the road aging state.

Aging Behavior of High-Viscosity Modified Asphalt Binder Based on Infrared Spectrum Test.

In the rapid development of sponge city construction in China, porous asphalt pavement has been widely used. The high-viscosity modified asphalt used for porous asphalt pavements is utilised in a complex aging environment. In this study, infrared spectroscopy was used to test the changes in the functional groups of high-viscosity modified asphalt under the influence of ultraviolet radiation intensity, high temperature, and water corrosion conditions. The research results showed that under the influence of several environmental factors, the high-viscosity modified asphalt has no chemical reaction but does undergo physical changes. From the perspective of the functional group index, the carbonyl index is more suitable for evaluating the degree of ultraviolet aging, and the sulfoxide group index is more suitable for evaluating the effect of temperature on aging. The high-viscosity modified asphalt aging kinetic models, established with different functional group indexes as indicators, have different activation energies. The aging kinetic model established with the carbonyl index is more suitable for simulating traditional thermal-oxidative aging. This study provides a better plan to reveal the influence of different environmental factors on the aging performance of high-viscosity modified asphalt under complex environmental conditions.

Study on the Effect of Regeneration Agent on the Viscosity Properties of Aged Asphalt.

China’s highway asphalt pavement has entered the stage of major repair, and improving the utilization rate of recycled asphalt pavement (RAP) is the main issue. The key link affecting the performance of recycled asphalt mixtures is the regeneration of aged asphalt, and the effect of the regenerant dosing on the high-temperature performance and viscosity of aged asphalt is the main content to be studied in this research. The aging behavior of asphalt seriously affects the roadworthiness of asphalt mixtures. In this study, we investigated the effect of changes in the microscopic properties of the aged asphalt on its viscosity properties during regeneration using gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM) as well as Brinell viscosity tests. This study simulated asphalt aging by the RTFOT test, and then we obtained an aged asphalt with a needle penetration of 30. We prepared different regenerated asphalts by adding regeneration agent with doses of 2%, 4%, and 6% to the aged asphalt. The results showed that the regeneration agent could effectively reduce the viscosity of the aged asphalt, which can play a positive role in improving the construction and ease of the aged asphalt. Rejuvenation agents affected the aging asphalt sulfoxide and carbon group indices. Moreover, rejuvenation agents can also significantly reduce the intensities of their characteristic functional group indices. The results of the AFM test showed that the increase in the dose of regeneration agent increased the number of the asphalt bee-like structures and decreased the area of individual bee-like structures. The results of the GPC test were consistent with the results of the AFM test, and the increase in the dose of regeneration agent reduced the asphalt macromolecule content. The viscosity properties and microstructure of the aged asphalt changed positively after the addition of the regeneration agent, indicating that the regeneration agent had a degrading and diluting effect on macromolecules.