Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic...Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic crude oil is unfit for the production of highway paving asphalts directly, Neither are the de-oiled asphalts of the YVR. In this research a blending method and an optimal process of solvent de-asphalts are adopted to investigate the feasibility of formulating highway-paving asphalts from YVR. Results show that highway paving asphalts are formulated by blending solvent de-oiled asphalts with one or more of the materials including YVR, decanted oil from FCC process, and furfural extracts from lubricating base stocks. Further investigations indicate that adding oil decanted from FCC process to the solvent de-asphalting process can increase the de-asphalted oil production, improve the de-oiled asphalts quality, and thus optimize the refinery processes. The methodology of this research can be extended even to refineries processing non-paraffinic crude oils.展开更多
Because of its economical and environmentally friendly characteristics, the warm mix asphalt(WMA) is widely used in pavement engineering. However, the lack of microscopic study of WMA brings difficulties in understand...Because of its economical and environmentally friendly characteristics, the warm mix asphalt(WMA) is widely used in pavement engineering. However, the lack of microscopic study of WMA brings difficulties in understanding of its mechanical behavior and mechanisms at macroscopic scale which finally hinders the enhancement of WMA's performance. Therefore, this article aims to use atomic force microscopy(AFM), a promising microscopic technique, to investigate the effects of wax-based warm mix agents on asphalt microstructures and micromechanical properties at different temperatures. For simplicity's sake, microcrystalline waxes are selected as an alternative of these wax-based additives. It is shown that the sample preparation method has a vital impact on the morphology of asphalt samples. The effects of microcrystalline wax on asphalt's mechanical properties can be well captured by AFM tests. Results show that the blending of #70, #80 and #90 microcrystalline waxes lowers the modulus(20—60 MPa) of Pen70 asphalt at 25 ℃ while increasing its adhesion force(5—20 n N). The results of this study may shed some light on the comprehension of the effects of wax-based additives on asphalt materials at macroscopic level which can help estimate and predict its actual performance.展开更多
Hard grade paving asphalts,i.e.,having a penetration at 25C lower than 25 mm/10,have experienced,in France,a significant development over the last forty years,linked to the development of high modulus asphalt concrete...Hard grade paving asphalts,i.e.,having a penetration at 25C lower than 25 mm/10,have experienced,in France,a significant development over the last forty years,linked to the development of high modulus asphalt concrete for rehabilitation then for new construction of road pavements.In the first part,this paper provides a review of the evolution of asphalts in France over the past sixty years towards the use of harder penetration grades and a limitation of the evolution of the asphalt in the mixing plant to avoid early cracking of the pavement.Current recommendations in relation to climatic conditions are mentioned.Rheological characteristics of different hard asphalts produced in France are presented including data on the effect of ageing tests rolling thin film oven test(RTFOT)and pressure ageing vessel(PAV).Hardening of hard asphalt after RTFOTþPAV is comparable to that of softer asphalts.The performance related to low temperature cracking is less which limits the use of plain hard asphalt in pavements subjected to severe winter conditions and requires polymer modification.The specifications for hard grade paving asphalts based on traditional empirical tests included in the European standard developed in the mid 2000s and the choices made in France are presented.A comparison of the specifications for hard grade paving asphalts in the European standards and of those proposed for China shows that the European specifications are more stringent as regards consistency and evolution after ageing tests.展开更多
To reduce the temperature diseases of asphalt pavement,improve the service quality of road and extend service life,the research of inorganic powders that reduce the temperature of asphalt pavements was systematically ...To reduce the temperature diseases of asphalt pavement,improve the service quality of road and extend service life,the research of inorganic powders that reduce the temperature of asphalt pavements was systematically sorted out.The common types,physicochemical properties and application methods of inorganic powders were defined.The road performances of modified asphalt and its mixture were evaluated.The modification mechanism of inorganic powders in asphalt was analyzed.On this basis,the cooling effect and cooling mechanism of inorganic powders was revealed.The results indicate that inorganic powders are classified into hollow,porous,and energy conversion types.The high-temperature performance of inorganic powders modified asphalt and its mixture is significantly improved,while there is no significant change in low-temperature performance and water stability.The average increase in rutting resistance factor(G*/sin(δ))and dynamic stability is 40%–72%and 30%–50%,respectively.The modification mechanism of inorganic powders in asphalt is physical blending.The thermal conductivity of hollow and porous inorganic powders modified asphalt mixture decreases by 30.05%and 43.14%,respectively.The temperature of hollow,porous and energy conversion inorganic powders modified asphalt mixture at 5 cm decreases by 2.3 ℃–3.5 ℃,0.8 ℃–3.7 ℃and 4.1 ℃–4.7℃,respectively.Hollow and porous inorganic powders block heat conduction,while energy conversion inorganic powders achieve cooling through their functional properties.展开更多
Determination of Shear Bond strength(SBS)at interlayer of double-layer asphalt concrete is crucial in flexible pavement structures.The study used three Machine Learning(ML)models,including K-Nearest Neighbors(KNN),Ext...Determination of Shear Bond strength(SBS)at interlayer of double-layer asphalt concrete is crucial in flexible pavement structures.The study used three Machine Learning(ML)models,including K-Nearest Neighbors(KNN),Extra Trees(ET),and Light Gradient Boosting Machine(LGBM),to predict SBS based on easily determinable input parameters.Also,the Grid Search technique was employed for hyper-parameter tuning of the ML models,and cross-validation and learning curve analysis were used for training the models.The models were built on a database of 240 experimental results and three input variables:temperature,normal pressure,and tack coat rate.Model validation was performed using three statistical criteria:the coefficient of determination(R2),the Root Mean Square Error(RMSE),and the mean absolute error(MAE).Additionally,SHAP analysis was also used to validate the importance of the input variables in the prediction of the SBS.Results show that these models accurately predict SBS,with LGBM providing outstanding performance.SHAP(Shapley Additive explanation)analysis for LGBM indicates that temperature is the most influential factor on SBS.Consequently,the proposed ML models can quickly and accurately predict SBS between two layers of asphalt concrete,serving practical applications in flexible pavement structure design.展开更多
This study investigates the mechanism of action of representative molecules of basalt fibers on the healing of water-soaked asphalt.Thermodynamic parameters,morphological characteristics,interfacial healing energy,and...This study investigates the mechanism of action of representative molecules of basalt fibers on the healing of water-soaked asphalt.Thermodynamic parameters,morphological characteristics,interfacial healing energy,and interfacial healing strength were analyzed using molecular dynamics and macroscopic tests under different time,temperature,and water conditions to evaluate the specific states and critical conditions involved in self-healing.The results indicate that basalt-fiber molecules can induce rearrangement and a combination of water-soaked asphalt at the healing interface.Hydroxyl groups with different bonding states increase the interfacial adsorption capacity of water-soaked asphalt.The interaction between basalt fiber molecules and water molecules leads to a"hoop"phenomenon,while aromatics-2 molecules exhibit a"ring band aggregation"phenomenon.The former reduces the miscibility of water and asphalt molecules,while the latter causes slow diffusion of the components.Furthermore,a micro-macro dual-scale comparison of interfacial healing strength was conducted at temperatures of 297.15 and 312.15 K to identify the strength transition point and critical temperature of 299.4 K during the self-healing process of basalt-fiber modified water-soaked asphalt.展开更多
Graphene oxide nanomaterials are increasingly used in various fields due to their superior properties.In order to study the influence of graphene oxide additives on the performance of modified asphalt,in this study,gr...Graphene oxide nanomaterials are increasingly used in various fields due to their superior properties.In order to study the influence of graphene oxide additives on the performance of modified asphalt,in this study,graphene oxide modified asphalt was prepared and characteristics was studied including the high deformation resistance performance and the self-healing property of modified asphalt.Functional groups and morphology of graphene oxide modified asphalt were described by Fourier transform infrared spectroscopy.The high deformation resistance performance and self-healing effect of asphalt samples were obtained through dynamic slear rheometer(DSR)test.Results shows that graphene oxide dispersions improve the performance of asphalt relatively well compared to graphene oxide powder.There is no chemical reaction between graphene oxide and asphalt,but physical connection.The addition of graphene oxide improved the high deformation resistance of modified asphalt and expedited the self-healing ability of asphalt under fatigue load.展开更多
Isocyanate and its products are playing an increasingly important role in the high-performance development of asphalt pavement,but researchers have always focused on polyurethane(PU),one of the isocyanate products,and...Isocyanate and its products are playing an increasingly important role in the high-performance development of asphalt pavement,but researchers have always focused on polyurethane(PU),one of the isocyanate products,and neglected the other roles of isocyanate-based materials in asphalt pavement.The application of isocyanate-based materials in asphalt pavement is still in the exploratory stage,and the research direction is not clear.It is necessary to summarize and propose research directions for the application of isocyanate-based materials in asphalt pavement.Therefore,this paper reviews the application of isocyanate-based materials in asphalt pavement,classifies the products synthesized from isocyanate for asphalt binder,introduces the application effects of different isocyanate-based materials in asphalt binder,and analyzes the limitations of each material.Meanwhile,the other roles of isocyanate-based materials in asphalt pavement,such as coating materials and adhesive materials,are summarized.Finally,the development direction of isocyanate-based materials in asphalt pavement is prospected.Isocyanate-based materials are expected to significantly increase the service life of asphalt pavement because of their excellent properties.With the advancement of technology,the application of isocyanate-based materials will become more and more common,promoting the sustainable development of road construction.This paper can provide a reference for the development and application of isocyanate-based materials in asphalt pavement.展开更多
The use of epoxy resin(EP)to prepare epoxy recycled asphalt mixture can achieve the reuse of 100%reclaimed asphalt pavement(RAP).However,the high stiffness and brittleness of epoxy resin result in insufficient crack r...The use of epoxy resin(EP)to prepare epoxy recycled asphalt mixture can achieve the reuse of 100%reclaimed asphalt pavement(RAP).However,the high stiffness and brittleness of epoxy resin result in insufficient crack resistance of mixture.To address the issue,dry-method styrene-butadiene-styrene(DSBS)and epoxy resin were mixed with aged asphalt to prepare SBS-modified epoxy reclaimed asphalt(SERA).The micro fusion characteristics and mechanical properties of SERA were evaluated,and the optimal DSBS dosage was determined based on various tests.The results show that adding DSBS can enable the tensile toughness and low-temperature performance of SERA with less EP content to reach or exceed the performance level of epoxy reclaimed asphalt(ERA)with higher EP content.At 30%EP content,the recommended dry-method SBS content is 9%;At 40%EP content,the recommended dry-method SBS content is 5%;When the EP content is 50%,the recommended dry-method SBS content is 7%.展开更多
The objective of this paper is to comprehensively review the research progress of bio-oil properties and hot rejuvenation behavior and mechanism to aged asphalt.The preparation process,composition characteristics of b...The objective of this paper is to comprehensively review the research progress of bio-oil properties and hot rejuvenation behavior and mechanism to aged asphalt.The preparation process,composition characteristics of bio-oils and their component correspondence with petroleum asphalt were compared.The diffusion and fusion effects of various bio-oils in aged asphalt were introduced.Bio-oil cannot be used as a direct alternative of petroleum asphalt,but it has the potential to effectively rejuvenate aged asphalt binders due to the component similarity with petroleum asphalt and good diffusion properties.For the asphalt rejuvenation,the functionalization treatment methods of bio-oil were discussed such as purification,composition modification and component conversion.The active groups and derivatives in bio-oil can be converted into the missing components of the aged binder through phenolate,grafting,polycondensation,resinifying,but the conversion process and mechanism are still unclear.From the perspectives of diffusion behavior,components regulation,dissolving asphaltene and micro-rejuvenation effect,the rejuvenation behavior and mechanism of bio-oil on aged asphalt were elaborated,and the effects of various types of bio-oil and aged asphalt on rejuvenation behavior were analyzed.The preparation process and dosage of bio-rejuvenator were summarized.The rejuvenation effects of bio-oil on aged asphalt were comprehensively investigated from the aspects of high and low temperature performances,rheological properties,microstructure and chemical composition of bio-rejuvenated asphalt binders.Finally,the limitations of bio-oil used as asphalt rejuvenators were discussed,and future research directions were prospected,which can provide reference and theoretical basis for the development of high-performance bio-oil rejuvenating agents and the engineering application of bio-oil to improve the properties of aged asphalt materials.展开更多
This study aims to investigate the intrinsic repair behavior of asphalt using molecular dynamics simulation.The Materials Studio software was employed to construct a virgin asphalt and SBS modified asphalt.The evaluat...This study aims to investigate the intrinsic repair behavior of asphalt using molecular dynamics simulation.The Materials Studio software was employed to construct a virgin asphalt and SBS modified asphalt.The evaluation of the two types of asphalt included diffusion coefficient,activation energy of diffusion,and pre-exponential factor.The self-healing performance of both virgin asphalt and SBS modified asphalt was then analyzed and verified through fatigue shear-healing tests.The molecular dynamics results indicate that the self-healing properties of both asphalts improve with increasing temperature.The time required for the cracked area to be filled was found to be shorter than the time needed for the asphalt material to recover its mechanical properties.Furthermore,the activation energy of diffusion for SBS modified asphalt was slightly higher compared to that of virgin asphalt,as observed in the experimental results.The self-healing speed and collision frequency of SBS modified asphalt were both faster than those of virgin asphalt,indicating that the self-healing performance of SBS modified asphalt is superior overall.展开更多
Presently,many asphalts and modified asphalts fail to satisfy long-term serviceability and durability criteria.Researchers are utilizing several asphalt modifiers to enhance the overall performance of flexible pavemen...Presently,many asphalts and modified asphalts fail to satisfy long-term serviceability and durability criteria.Researchers are utilizing several asphalt modifiers to enhance the overall performance of flexible pavements.This study consolidated findings from multiple research efforts on using nanomaterials for modifying SBS modified asphalt(SBS MA)and conducted a comprehensive literature review.Initially,it discussed the importance of SBS MA within asphalt modification systems and identified the key nanomaterials utilized in SBS modified asphalt.After this,it reviewed their preparation methods,dispersion and characterization techniques,and their impact on the key performance parameters of SBS MA binder and its mixture such as viscosity,rutting resistance,fatigue resistance,ageing and moisture damage etc.Additionally,it highlighted the advantages of nanomaterials over other modifiers.This study also addressed the challenges and limitations of incorporating nanomaterials in SBS MA.The findings indicated that when properly integrated,nanomaterials could significantly improve the performance of SBS MA,making them a promising addition to future road construction and maintenance projects.However,using nanomaterials for SBS MA modifications and mixtures has been challenged by limited practical applications,insufficient life cycle cost analyses,a lack of standardized guidelines,cost-effective nanomaterials and insufficient mixing procedures.Those areas require additional research to realise the potential application of nanomaterials in SBS modified asphalt modifications full.展开更多
Styrene-butadiene-styrene(SBS)modified asphalt(SA)has long found effective applications in road construction materials.When combined with fillers,SBS-modified asphalt has demonstrated promising resistance to fatigue c...Styrene-butadiene-styrene(SBS)modified asphalt(SA)has long found effective applications in road construction materials.When combined with fillers,SBS-modified asphalt has demonstrated promising resistance to fatigue cracking caused by temperature fluctuations and aging.In this study,molybdenum disulfide(MoS_(2))and polyphosphoric acid(PPA)were ground in naphthenic oil(NO)and subjected to mechanical activation to create PPAmodified MoS_(2),referred to as OMS-PPA.By blending various ratios of OMS-PPA with SBS-modified asphalt,composite-modified asphalts were successfully developed to enhance their overall properties.To assess the mechanical characteristics and stability of these modified asphalts,various methods were employed,including penetration factor,flow activation energy,fluorescence microscopy,and dynamic shear rheology.Additionally,the short-term aging performance was evaluated using Fourier transform infrared(FTIR)spectroscopy and nanoindentation tests.The results revealed a 3.7%decrease in the penetration-temperature coefficient for SAOMS compared to SA,while 1-SA-OMS-PPA showed an even greater reduction of 7.1%.Furthermore,after short-term aging,carboxyl group generation in SA increased by 5.93%,while SA-OMS exhibited a smaller rise of 1.36%,and 1-SA-OMS-PPA saw an increase of just 0.93%.The study also highlighted significant improvements in the hardness of these materials.The hardness change ratio for SA-OMS decreased by 43.08%,while the ratio for 1-SA-OMS-PPA saw a notable reduction of 65.16% compared to unmodified SA.These findings suggest that OMS-PPA contributed to improvements in temperature sensitivity,particle dispersibility,and resistance to shortterm aging in asphalts.The results hold significant promise for the future development of advanced asphalt-based materials with potential high-value applications in flexible pavements for highways.展开更多
The utilization of reclaimed asphalt pavement(RAP)in asphalt mixtures has gained momentum in recent years,yet concerns persist regarding the long-term performance and binder properties of high RAP content mixtures.To ...The utilization of reclaimed asphalt pavement(RAP)in asphalt mixtures has gained momentum in recent years,yet concerns persist regarding the long-term performance and binder properties of high RAP content mixtures.To overcome these challenges,rejuvenators have emerged as a promising solution to enhance the properties of aged asphalt binders and improve the overall performance of asphalt mixtures.This paper provides a comprehensive state-of-the-art review of rejuvenator technology and its potential to enhance the performance and sustainability of asphalt pavements.Rejuvenators are additives used to restore the properties of aged asphalt binders,particularly when incorporating high percentages of RAP.The performance of these additives varies based on their origin,and different methods can be used to analyze the rejuvenation process.Since proper specifications for rejuvenators are not available,blending charts are used to determine the optimum dosage of rejuvenators.However,proper blending must be achieved to maximize results and reduce the effect of black rock.Laboratory tests and some field performance studies on rejuvenated aged asphalt binders and RAP mixtures have shown improved or similar performance compared to virgin materials.Additionally,the use of rejuvenators has been observed to reduce construction costs,suggesting that this is a cost-effective technology for asphalt pavements.While rejuvenators show promise in improving the performance of pavements with recycled materials,challenges remain regarding optimization,long-term durability,and environmental effects.This review paper also identifies key areas for future research,including life-cycle cost analyses,comprehensive environmental impact assessments,and long-term field performance monitoring.展开更多
Enhancing rubber-bitumen compatibility is crucial to improve pavement performance and durability.To investigate the compatibility improvement between H2O2-activated waste crumb rubber(AWCR)and bitumen,coarse and fine ...Enhancing rubber-bitumen compatibility is crucial to improve pavement performance and durability.To investigate the compatibility improvement between H2O2-activated waste crumb rubber(AWCR)and bitumen,coarse and fine waste crumb rubber(WCR)were treated and analyzed through multi-scale characterization and molecular simulation.Microstructure and chemical changes of WCR and AWCR were analyzed with scanning electron microscope(SEM),contact angle tests and Fourier transform infrared spectroscopy(FTIR).Compatibility was also indirectly evaluated through modified boiling tests and storage stability tests.Besides,molecular dynamics was used to explore the interaction between WCR/AWCR and bitumen.SEM,contact angle,and FTIR results showed bond breakage of C=C and C–C and increased polar groups like–OH and–COOH in AWCR,resulting in a rougher texture and higher surface energy.Compared with WCR,AWCR showed a lower bitumen stripping rate after boiling,and the binder with AWCR also had a lower softening point difference and segregation rate after storage.Molecular dynamics simulations further confirmed that AWCR has a closer solubility parameter and higher binding energy to bitumen than WCR,reflected in a relatively slower diffusion rate.This study provides comprehensive evidence for an eco-friendly method of WCR surface treatment for more efficient recycling of tire rubber in asphalt pavements.展开更多
The asphalt pavement industry is transforming because of the growing influence of artificial intelligence and industrial digitization.As a result of this shift,there is a stronger emphasis on advanced statistical appr...The asphalt pavement industry is transforming because of the growing influence of artificial intelligence and industrial digitization.As a result of this shift,there is a stronger emphasis on advanced statistical approaches like optimization tools like response surface methodology(RSM)and machine learning(ML)techniques.The goal of this paper is to provide a scientometric and systematic review of the application of RSM and ML applications in data-driven approaches such as optimizing,modeling,and predicting asphalt pavement performance to achieve sustainable asphalt pavements in support of numerous sustainable development goals(SDGs).These include Goals 9(sustainable infrastructure),11(urban resilience),12(sustainable construction strategies),13(climate action through optimized materials),and 17(multidisciplinary interaction).A thorough search of the ScienceDirect,Web of Science,and Scopus databases from 2010 to 2023 yielded 1249 relevant records,with 125 studies closely examined.Over the last thirteen years,there has been significant research growth in RSM and ML applications,particularly in ML-based pavement optimization.The study shows that the topic has a global presence,with notable contributions from Asia,North America,Europe,and other continents.Researchers have concentrated on utilizing sophisticated ML models such as support vector machines(SVM),artificial neural networks(ANN),and Bayesian networks for prediction.Also,the integration of RSM and ML provides a faster and more efficient method for analyzing large datasets to optimize asphalt pavement performance variables.Key contributors include the United States,China,and Malaysia,with global efforts focused on sustainable materials and approaches to reduce impact on the environment.Furthermore,the review demonstrates the integrated use of RSM and ML as transformative tools for improving sustainability,which contributes significantly to SDGs 9,11,12,13,and 17.Providing valuable insights for future research and guiding decision-making for soft computing applications for asphalt pavement projects.展开更多
This research examined the feasibility of incorporating electric arc furnace(EAF)slag and waste plastic into stone matrix asphalt(SMA)mixtures.With annual global production of over 70 million tons of EAF slag and 300 ...This research examined the feasibility of incorporating electric arc furnace(EAF)slag and waste plastic into stone matrix asphalt(SMA)mixtures.With annual global production of over 70 million tons of EAF slag and 300 million tons of plastic waste,repurposing these materials could yield substantial environmental benefits.The research evaluated SMA mixtures with EAF slag as aggregate replacement and waste plastic as a binder modifier.The research aimed to develop sustainable SMA formulations while promoting recycling of industrial byproducts.Laboratory experiments were conducted to evaluate mix design characteristics,drain-down potential,abrasion resistance,rutting resistance,moisture susceptibility,fatigue performance,and stiffness of modified SMA mixtures.The addition of waste plastic,ranging from 4%,6%,8%and 12%by weight of bitumen,demonstrated significant improvements in key properties.Results showed that waste plastic reduced the optimum binder content and increased voids in the mineral aggregate.EAF slag mixtures demonstrated improved drain-down characteristics and moisture susceptibility.Both rutting resistance and fatigue life increased significantly with waste plastic content,with EAF slag mixtures consistently outperforming those made with conventional aggregates.Ultrasonic pulse velocity tests indicated higher stiffness in modified mixtures.The optimal waste plastic content was determined to be 8%by weight of bitumen.Statistical analysis confirmed significant effects of both EAF slag and waste plastic on multiple performance parameters.These findings highlight the potential of incorporating industrial byproducts into SMA mixtures to achieve high-performance road construction solutions,offering a viable pathway for addressing global waste management challenges.展开更多
Road pavements in tunnels are usually made of asphalt mixtures,which,unfortunately,are flammable materials.Hence,this type of pavement could release heat,and more specifically smoke,in the event of a tunnel fire,there...Road pavements in tunnels are usually made of asphalt mixtures,which,unfortunately,are flammable materials.Hence,this type of pavement could release heat,and more specifically smoke,in the event of a tunnel fire,thereby worsening the environmental conditions for human health.Extensive research has been conducted in recent years to enhance the fire reaction of traditional asphalt mixtures for the road pavements used in tunnels.The addition of the Flame Retardants(FRs)in conventional asphalt mixtures appears to be promising.Nevertheless,the potential effects of the FRs in terms of the reduction in consequences on tunnel users in the event of a large fire do not seem to have been sufficiently investigated by using fluid dynamics analysis as a computational tool.Given this gap of knowledge,this article aims to quantitatively evaluate whether the use of flame-retarded asphalt mixtures,as opposed to traditional ones without FRs,might mitigate the adverse effects on the safety of evacuees and fire brigade by performing numerical analyses in the case of a tunnel fire.To achieve this goal,3D Computational Fluid Dynamics(CFD)models,which were executed using the Fire Dynamics Simulator(FDS)tool,were established in the case of a major fire of a Heavy Goods Vehicle(HGV)characterized by a maximum Heat Release Rate(HRRmax)of 100 MW.The people evacuation process was also simulated,and the Evac tool was used.Compared to the traditional asphalt pavements without FRs,the simulation findings indicated that the addition of the FRs causes a reduction in CO and CO_(2)levels in the tunnel during the aforementioned fire,with a minor number of evacuees being exposed to the risk of incapacity to self-evacuate,as well as certain safety benefits for the operability of the firefighters entering the tunnel downstream of the fire when the tunnel is naturally ventilated.展开更多
Along with the surging demand for energy storage devices,the cost and availability of the materials remain dominant factors in slowing down their industrial application.The repurposing of waste asphalt into high-perfo...Along with the surging demand for energy storage devices,the cost and availability of the materials remain dominant factors in slowing down their industrial application.The repurposing of waste asphalt into high-performance electrode materials is of significant interest,as it holds the potential to circumvent energy and environmental issues.Here,we report the controllable synthesis of asphalt-derived mesoporous carbon as an active material for electrocatalytic hydrogen gas capacitor(EHGC).The hierarchically porous carbon(HPC)with a high surface area of 1943.4 m^(2)·g^(-1)can operate in pH universal aqueous electrolytes in EHGC.It displays a specific energy and power density of 57 Wh·kg^(-1)and 554 W·kg^(-1)in neutral electrolyte as well as 52 Wh·kg^(-1)and 657 W·kg^(-1)in acidic electrolyte.Additionally,the charge storage mechanism of HPC-EHGC is studied with the help of Raman spectroscopy and X-ray photoelectron spectroscopy.Furthermore,the assembled HPC-EHGC device displays a discharge capacitance of 170 F·g^(-1)with an excellent capacitance retention rate of 100%up to 20000 cycles at 10 A·g^(-1)in acidic electrolyte.This work introduces a novel approach to converting waste asphalt into high-performance carbon for EHGC,achieving superior performance over commercial materials.By simultaneously addressing environmental waste issues and advancing energy storage technology,this study makes a significant contribution to sustainable materials science and next-generation battery development.展开更多
The elevated temperatures adversely affect the durability and lifespan of pavement.Understanding the factors that influence asphalt pavement temperature offers valuable insights for creating climate-friendly cities wi...The elevated temperatures adversely affect the durability and lifespan of pavement.Understanding the factors that influence asphalt pavement temperature offers valuable insights for creating climate-friendly cities with cooler pavement surfaces.In this study,three aggregates of varying types and colors,two types of bitumen(one without pigment and one with the addition of red pigment,Fe2O3),and two levels of mean texture depth(MTD),high and low,were utilized to create asphalt samples using Marshall's method.A total of 38 thermocouple sensors were employed to simultaneously record temperatures in three areas within the samples,as well as the temperatures in shaded and sunlit conditions over a period of 17 days.Furthermore,a comprehensive evaluation was conducted to assess the impact of each factor on the solar reflectance index(SRI).Twelve general linear models(GLMs)were developed using a full factorial design of experiment,and five models with an R2 greater than 95%were evaluated and analyzed.The analysis,based on the coefficients derived from the GLMs,indicates that the mean MTD is the most significant parameter affecting surface temperature.Pigment color emerged as the second most influential factor affecting both surface and bottom temperatures.Additionally,the findings revealed that MTD has the greatest impact on the SRI,followed by pigment color and aggregate color.It was also determined that the interaction between density,pigment color,and aggregate color plays a crucial role in determining the temperatures of both the surface and bottom of the specimens.展开更多
文摘Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic crude oil is unfit for the production of highway paving asphalts directly, Neither are the de-oiled asphalts of the YVR. In this research a blending method and an optimal process of solvent de-asphalts are adopted to investigate the feasibility of formulating highway-paving asphalts from YVR. Results show that highway paving asphalts are formulated by blending solvent de-oiled asphalts with one or more of the materials including YVR, decanted oil from FCC process, and furfural extracts from lubricating base stocks. Further investigations indicate that adding oil decanted from FCC process to the solvent de-asphalting process can increase the de-asphalted oil production, improve the de-oiled asphalts quality, and thus optimize the refinery processes. The methodology of this research can be extended even to refineries processing non-paraffinic crude oils.
基金financial support of the Education Department of Jiangsu Province under Grant No.JZ-007the Jiangsu Natural Science Foundation under Grant No.BK 20140111
文摘Because of its economical and environmentally friendly characteristics, the warm mix asphalt(WMA) is widely used in pavement engineering. However, the lack of microscopic study of WMA brings difficulties in understanding of its mechanical behavior and mechanisms at macroscopic scale which finally hinders the enhancement of WMA's performance. Therefore, this article aims to use atomic force microscopy(AFM), a promising microscopic technique, to investigate the effects of wax-based warm mix agents on asphalt microstructures and micromechanical properties at different temperatures. For simplicity's sake, microcrystalline waxes are selected as an alternative of these wax-based additives. It is shown that the sample preparation method has a vital impact on the morphology of asphalt samples. The effects of microcrystalline wax on asphalt's mechanical properties can be well captured by AFM tests. Results show that the blending of #70, #80 and #90 microcrystalline waxes lowers the modulus(20—60 MPa) of Pen70 asphalt at 25 ℃ while increasing its adhesion force(5—20 n N). The results of this study may shed some light on the comprehension of the effects of wax-based additives on asphalt materials at macroscopic level which can help estimate and predict its actual performance.
文摘Hard grade paving asphalts,i.e.,having a penetration at 25C lower than 25 mm/10,have experienced,in France,a significant development over the last forty years,linked to the development of high modulus asphalt concrete for rehabilitation then for new construction of road pavements.In the first part,this paper provides a review of the evolution of asphalts in France over the past sixty years towards the use of harder penetration grades and a limitation of the evolution of the asphalt in the mixing plant to avoid early cracking of the pavement.Current recommendations in relation to climatic conditions are mentioned.Rheological characteristics of different hard asphalts produced in France are presented including data on the effect of ageing tests rolling thin film oven test(RTFOT)and pressure ageing vessel(PAV).Hardening of hard asphalt after RTFOTþPAV is comparable to that of softer asphalts.The performance related to low temperature cracking is less which limits the use of plain hard asphalt in pavements subjected to severe winter conditions and requires polymer modification.The specifications for hard grade paving asphalts based on traditional empirical tests included in the European standard developed in the mid 2000s and the choices made in France are presented.A comparison of the specifications for hard grade paving asphalts in the European standards and of those proposed for China shows that the European specifications are more stringent as regards consistency and evolution after ageing tests.
基金supported by Fundamental Research Funds for the Central Universities(300102214908)Innovation Capability Support Program of Shaanxi(2022TD-07).
文摘To reduce the temperature diseases of asphalt pavement,improve the service quality of road and extend service life,the research of inorganic powders that reduce the temperature of asphalt pavements was systematically sorted out.The common types,physicochemical properties and application methods of inorganic powders were defined.The road performances of modified asphalt and its mixture were evaluated.The modification mechanism of inorganic powders in asphalt was analyzed.On this basis,the cooling effect and cooling mechanism of inorganic powders was revealed.The results indicate that inorganic powders are classified into hollow,porous,and energy conversion types.The high-temperature performance of inorganic powders modified asphalt and its mixture is significantly improved,while there is no significant change in low-temperature performance and water stability.The average increase in rutting resistance factor(G*/sin(δ))and dynamic stability is 40%–72%and 30%–50%,respectively.The modification mechanism of inorganic powders in asphalt is physical blending.The thermal conductivity of hollow and porous inorganic powders modified asphalt mixture decreases by 30.05%and 43.14%,respectively.The temperature of hollow,porous and energy conversion inorganic powders modified asphalt mixture at 5 cm decreases by 2.3 ℃–3.5 ℃,0.8 ℃–3.7 ℃and 4.1 ℃–4.7℃,respectively.Hollow and porous inorganic powders block heat conduction,while energy conversion inorganic powders achieve cooling through their functional properties.
基金the University of Transport Technology under grant number DTTD2022-12.
文摘Determination of Shear Bond strength(SBS)at interlayer of double-layer asphalt concrete is crucial in flexible pavement structures.The study used three Machine Learning(ML)models,including K-Nearest Neighbors(KNN),Extra Trees(ET),and Light Gradient Boosting Machine(LGBM),to predict SBS based on easily determinable input parameters.Also,the Grid Search technique was employed for hyper-parameter tuning of the ML models,and cross-validation and learning curve analysis were used for training the models.The models were built on a database of 240 experimental results and three input variables:temperature,normal pressure,and tack coat rate.Model validation was performed using three statistical criteria:the coefficient of determination(R2),the Root Mean Square Error(RMSE),and the mean absolute error(MAE).Additionally,SHAP analysis was also used to validate the importance of the input variables in the prediction of the SBS.Results show that these models accurately predict SBS,with LGBM providing outstanding performance.SHAP(Shapley Additive explanation)analysis for LGBM indicates that temperature is the most influential factor on SBS.Consequently,the proposed ML models can quickly and accurately predict SBS between two layers of asphalt concrete,serving practical applications in flexible pavement structure design.
文摘This study investigates the mechanism of action of representative molecules of basalt fibers on the healing of water-soaked asphalt.Thermodynamic parameters,morphological characteristics,interfacial healing energy,and interfacial healing strength were analyzed using molecular dynamics and macroscopic tests under different time,temperature,and water conditions to evaluate the specific states and critical conditions involved in self-healing.The results indicate that basalt-fiber molecules can induce rearrangement and a combination of water-soaked asphalt at the healing interface.Hydroxyl groups with different bonding states increase the interfacial adsorption capacity of water-soaked asphalt.The interaction between basalt fiber molecules and water molecules leads to a"hoop"phenomenon,while aromatics-2 molecules exhibit a"ring band aggregation"phenomenon.The former reduces the miscibility of water and asphalt molecules,while the latter causes slow diffusion of the components.Furthermore,a micro-macro dual-scale comparison of interfacial healing strength was conducted at temperatures of 297.15 and 312.15 K to identify the strength transition point and critical temperature of 299.4 K during the self-healing process of basalt-fiber modified water-soaked asphalt.
基金supported by Gansu Provincial Science and Technology Plan(23CXGA0195)Longnan Science and Technology Plan(2024CX03)。
文摘Graphene oxide nanomaterials are increasingly used in various fields due to their superior properties.In order to study the influence of graphene oxide additives on the performance of modified asphalt,in this study,graphene oxide modified asphalt was prepared and characteristics was studied including the high deformation resistance performance and the self-healing property of modified asphalt.Functional groups and morphology of graphene oxide modified asphalt were described by Fourier transform infrared spectroscopy.The high deformation resistance performance and self-healing effect of asphalt samples were obtained through dynamic slear rheometer(DSR)test.Results shows that graphene oxide dispersions improve the performance of asphalt relatively well compared to graphene oxide powder.There is no chemical reaction between graphene oxide and asphalt,but physical connection.The addition of graphene oxide improved the high deformation resistance of modified asphalt and expedited the self-healing ability of asphalt under fatigue load.
基金The authors are appreciative of the financial assistance granted by the National Natural Science Foundation of China(No.52378462)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011448).
文摘Isocyanate and its products are playing an increasingly important role in the high-performance development of asphalt pavement,but researchers have always focused on polyurethane(PU),one of the isocyanate products,and neglected the other roles of isocyanate-based materials in asphalt pavement.The application of isocyanate-based materials in asphalt pavement is still in the exploratory stage,and the research direction is not clear.It is necessary to summarize and propose research directions for the application of isocyanate-based materials in asphalt pavement.Therefore,this paper reviews the application of isocyanate-based materials in asphalt pavement,classifies the products synthesized from isocyanate for asphalt binder,introduces the application effects of different isocyanate-based materials in asphalt binder,and analyzes the limitations of each material.Meanwhile,the other roles of isocyanate-based materials in asphalt pavement,such as coating materials and adhesive materials,are summarized.Finally,the development direction of isocyanate-based materials in asphalt pavement is prospected.Isocyanate-based materials are expected to significantly increase the service life of asphalt pavement because of their excellent properties.With the advancement of technology,the application of isocyanate-based materials will become more and more common,promoting the sustainable development of road construction.This paper can provide a reference for the development and application of isocyanate-based materials in asphalt pavement.
基金Funded by the National Natural Science Foundation of China(Nos.52378444,52078130)the Natural Science Foundation of Shandong Province(No.ZR2021QE250)。
文摘The use of epoxy resin(EP)to prepare epoxy recycled asphalt mixture can achieve the reuse of 100%reclaimed asphalt pavement(RAP).However,the high stiffness and brittleness of epoxy resin result in insufficient crack resistance of mixture.To address the issue,dry-method styrene-butadiene-styrene(DSBS)and epoxy resin were mixed with aged asphalt to prepare SBS-modified epoxy reclaimed asphalt(SERA).The micro fusion characteristics and mechanical properties of SERA were evaluated,and the optimal DSBS dosage was determined based on various tests.The results show that adding DSBS can enable the tensile toughness and low-temperature performance of SERA with less EP content to reach or exceed the performance level of epoxy reclaimed asphalt(ERA)with higher EP content.At 30%EP content,the recommended dry-method SBS content is 9%;At 40%EP content,the recommended dry-method SBS content is 5%;When the EP content is 50%,the recommended dry-method SBS content is 7%.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52378432 and 52278426)the Key Research and Development Program of Shaanxi Province(Grant No.2022SF-169).
文摘The objective of this paper is to comprehensively review the research progress of bio-oil properties and hot rejuvenation behavior and mechanism to aged asphalt.The preparation process,composition characteristics of bio-oils and their component correspondence with petroleum asphalt were compared.The diffusion and fusion effects of various bio-oils in aged asphalt were introduced.Bio-oil cannot be used as a direct alternative of petroleum asphalt,but it has the potential to effectively rejuvenate aged asphalt binders due to the component similarity with petroleum asphalt and good diffusion properties.For the asphalt rejuvenation,the functionalization treatment methods of bio-oil were discussed such as purification,composition modification and component conversion.The active groups and derivatives in bio-oil can be converted into the missing components of the aged binder through phenolate,grafting,polycondensation,resinifying,but the conversion process and mechanism are still unclear.From the perspectives of diffusion behavior,components regulation,dissolving asphaltene and micro-rejuvenation effect,the rejuvenation behavior and mechanism of bio-oil on aged asphalt were elaborated,and the effects of various types of bio-oil and aged asphalt on rejuvenation behavior were analyzed.The preparation process and dosage of bio-rejuvenator were summarized.The rejuvenation effects of bio-oil on aged asphalt were comprehensively investigated from the aspects of high and low temperature performances,rheological properties,microstructure and chemical composition of bio-rejuvenated asphalt binders.Finally,the limitations of bio-oil used as asphalt rejuvenators were discussed,and future research directions were prospected,which can provide reference and theoretical basis for the development of high-performance bio-oil rejuvenating agents and the engineering application of bio-oil to improve the properties of aged asphalt materials.
基金Funded by the National Natural Science Foundation of China(No.52278446)。
文摘This study aims to investigate the intrinsic repair behavior of asphalt using molecular dynamics simulation.The Materials Studio software was employed to construct a virgin asphalt and SBS modified asphalt.The evaluation of the two types of asphalt included diffusion coefficient,activation energy of diffusion,and pre-exponential factor.The self-healing performance of both virgin asphalt and SBS modified asphalt was then analyzed and verified through fatigue shear-healing tests.The molecular dynamics results indicate that the self-healing properties of both asphalts improve with increasing temperature.The time required for the cracked area to be filled was found to be shorter than the time needed for the asphalt material to recover its mechanical properties.Furthermore,the activation energy of diffusion for SBS modified asphalt was slightly higher compared to that of virgin asphalt,as observed in the experimental results.The self-healing speed and collision frequency of SBS modified asphalt were both faster than those of virgin asphalt,indicating that the self-healing performance of SBS modified asphalt is superior overall.
基金supported by the Key R&D Project in Shaanxi Province(No.2024GX-YBXM-371)Shaanxi Qinchuangyuan“Scientists+Engineers”Team Construction Project(2025QCY-KXJ-141).
文摘Presently,many asphalts and modified asphalts fail to satisfy long-term serviceability and durability criteria.Researchers are utilizing several asphalt modifiers to enhance the overall performance of flexible pavements.This study consolidated findings from multiple research efforts on using nanomaterials for modifying SBS modified asphalt(SBS MA)and conducted a comprehensive literature review.Initially,it discussed the importance of SBS MA within asphalt modification systems and identified the key nanomaterials utilized in SBS modified asphalt.After this,it reviewed their preparation methods,dispersion and characterization techniques,and their impact on the key performance parameters of SBS MA binder and its mixture such as viscosity,rutting resistance,fatigue resistance,ageing and moisture damage etc.Additionally,it highlighted the advantages of nanomaterials over other modifiers.This study also addressed the challenges and limitations of incorporating nanomaterials in SBS MA.The findings indicated that when properly integrated,nanomaterials could significantly improve the performance of SBS MA,making them a promising addition to future road construction and maintenance projects.However,using nanomaterials for SBS MA modifications and mixtures has been challenged by limited practical applications,insufficient life cycle cost analyses,a lack of standardized guidelines,cost-effective nanomaterials and insufficient mixing procedures.Those areas require additional research to realise the potential application of nanomaterials in SBS modified asphalt modifications full.
基金financially supported by the Key Research and Development Program of Hubei Province(Nos.2022BCA077 and 2022BCA082).
文摘Styrene-butadiene-styrene(SBS)modified asphalt(SA)has long found effective applications in road construction materials.When combined with fillers,SBS-modified asphalt has demonstrated promising resistance to fatigue cracking caused by temperature fluctuations and aging.In this study,molybdenum disulfide(MoS_(2))and polyphosphoric acid(PPA)were ground in naphthenic oil(NO)and subjected to mechanical activation to create PPAmodified MoS_(2),referred to as OMS-PPA.By blending various ratios of OMS-PPA with SBS-modified asphalt,composite-modified asphalts were successfully developed to enhance their overall properties.To assess the mechanical characteristics and stability of these modified asphalts,various methods were employed,including penetration factor,flow activation energy,fluorescence microscopy,and dynamic shear rheology.Additionally,the short-term aging performance was evaluated using Fourier transform infrared(FTIR)spectroscopy and nanoindentation tests.The results revealed a 3.7%decrease in the penetration-temperature coefficient for SAOMS compared to SA,while 1-SA-OMS-PPA showed an even greater reduction of 7.1%.Furthermore,after short-term aging,carboxyl group generation in SA increased by 5.93%,while SA-OMS exhibited a smaller rise of 1.36%,and 1-SA-OMS-PPA saw an increase of just 0.93%.The study also highlighted significant improvements in the hardness of these materials.The hardness change ratio for SA-OMS decreased by 43.08%,while the ratio for 1-SA-OMS-PPA saw a notable reduction of 65.16% compared to unmodified SA.These findings suggest that OMS-PPA contributed to improvements in temperature sensitivity,particle dispersibility,and resistance to shortterm aging in asphalts.The results hold significant promise for the future development of advanced asphalt-based materials with potential high-value applications in flexible pavements for highways.
基金the Office of Research&Economic Development and Department of Civil,Coastal and Environmental Engineering at University of South Alabama for the support.
文摘The utilization of reclaimed asphalt pavement(RAP)in asphalt mixtures has gained momentum in recent years,yet concerns persist regarding the long-term performance and binder properties of high RAP content mixtures.To overcome these challenges,rejuvenators have emerged as a promising solution to enhance the properties of aged asphalt binders and improve the overall performance of asphalt mixtures.This paper provides a comprehensive state-of-the-art review of rejuvenator technology and its potential to enhance the performance and sustainability of asphalt pavements.Rejuvenators are additives used to restore the properties of aged asphalt binders,particularly when incorporating high percentages of RAP.The performance of these additives varies based on their origin,and different methods can be used to analyze the rejuvenation process.Since proper specifications for rejuvenators are not available,blending charts are used to determine the optimum dosage of rejuvenators.However,proper blending must be achieved to maximize results and reduce the effect of black rock.Laboratory tests and some field performance studies on rejuvenated aged asphalt binders and RAP mixtures have shown improved or similar performance compared to virgin materials.Additionally,the use of rejuvenators has been observed to reduce construction costs,suggesting that this is a cost-effective technology for asphalt pavements.While rejuvenators show promise in improving the performance of pavements with recycled materials,challenges remain regarding optimization,long-term durability,and environmental effects.This review paper also identifies key areas for future research,including life-cycle cost analyses,comprehensive environmental impact assessments,and long-term field performance monitoring.
基金supported by the research project“Green-health-safety Nexus for New Urban Spaces-GreeNexUS”(HORIZON MSCA-2021 DN,Marie Sklodowska-Curie Actions)Grant Agreement No.101073437:research grant under the title"Impact Absorbing Pavements with Improved Accessibility Features(DC9-IAP)".
文摘Enhancing rubber-bitumen compatibility is crucial to improve pavement performance and durability.To investigate the compatibility improvement between H2O2-activated waste crumb rubber(AWCR)and bitumen,coarse and fine waste crumb rubber(WCR)were treated and analyzed through multi-scale characterization and molecular simulation.Microstructure and chemical changes of WCR and AWCR were analyzed with scanning electron microscope(SEM),contact angle tests and Fourier transform infrared spectroscopy(FTIR).Compatibility was also indirectly evaluated through modified boiling tests and storage stability tests.Besides,molecular dynamics was used to explore the interaction between WCR/AWCR and bitumen.SEM,contact angle,and FTIR results showed bond breakage of C=C and C–C and increased polar groups like–OH and–COOH in AWCR,resulting in a rougher texture and higher surface energy.Compared with WCR,AWCR showed a lower bitumen stripping rate after boiling,and the binder with AWCR also had a lower softening point difference and segregation rate after storage.Molecular dynamics simulations further confirmed that AWCR has a closer solubility parameter and higher binding energy to bitumen than WCR,reflected in a relatively slower diffusion rate.This study provides comprehensive evidence for an eco-friendly method of WCR surface treatment for more efficient recycling of tire rubber in asphalt pavements.
文摘The asphalt pavement industry is transforming because of the growing influence of artificial intelligence and industrial digitization.As a result of this shift,there is a stronger emphasis on advanced statistical approaches like optimization tools like response surface methodology(RSM)and machine learning(ML)techniques.The goal of this paper is to provide a scientometric and systematic review of the application of RSM and ML applications in data-driven approaches such as optimizing,modeling,and predicting asphalt pavement performance to achieve sustainable asphalt pavements in support of numerous sustainable development goals(SDGs).These include Goals 9(sustainable infrastructure),11(urban resilience),12(sustainable construction strategies),13(climate action through optimized materials),and 17(multidisciplinary interaction).A thorough search of the ScienceDirect,Web of Science,and Scopus databases from 2010 to 2023 yielded 1249 relevant records,with 125 studies closely examined.Over the last thirteen years,there has been significant research growth in RSM and ML applications,particularly in ML-based pavement optimization.The study shows that the topic has a global presence,with notable contributions from Asia,North America,Europe,and other continents.Researchers have concentrated on utilizing sophisticated ML models such as support vector machines(SVM),artificial neural networks(ANN),and Bayesian networks for prediction.Also,the integration of RSM and ML provides a faster and more efficient method for analyzing large datasets to optimize asphalt pavement performance variables.Key contributors include the United States,China,and Malaysia,with global efforts focused on sustainable materials and approaches to reduce impact on the environment.Furthermore,the review demonstrates the integrated use of RSM and ML as transformative tools for improving sustainability,which contributes significantly to SDGs 9,11,12,13,and 17.Providing valuable insights for future research and guiding decision-making for soft computing applications for asphalt pavement projects.
文摘This research examined the feasibility of incorporating electric arc furnace(EAF)slag and waste plastic into stone matrix asphalt(SMA)mixtures.With annual global production of over 70 million tons of EAF slag and 300 million tons of plastic waste,repurposing these materials could yield substantial environmental benefits.The research evaluated SMA mixtures with EAF slag as aggregate replacement and waste plastic as a binder modifier.The research aimed to develop sustainable SMA formulations while promoting recycling of industrial byproducts.Laboratory experiments were conducted to evaluate mix design characteristics,drain-down potential,abrasion resistance,rutting resistance,moisture susceptibility,fatigue performance,and stiffness of modified SMA mixtures.The addition of waste plastic,ranging from 4%,6%,8%and 12%by weight of bitumen,demonstrated significant improvements in key properties.Results showed that waste plastic reduced the optimum binder content and increased voids in the mineral aggregate.EAF slag mixtures demonstrated improved drain-down characteristics and moisture susceptibility.Both rutting resistance and fatigue life increased significantly with waste plastic content,with EAF slag mixtures consistently outperforming those made with conventional aggregates.Ultrasonic pulse velocity tests indicated higher stiffness in modified mixtures.The optimal waste plastic content was determined to be 8%by weight of bitumen.Statistical analysis confirmed significant effects of both EAF slag and waste plastic on multiple performance parameters.These findings highlight the potential of incorporating industrial byproducts into SMA mixtures to achieve high-performance road construction solutions,offering a viable pathway for addressing global waste management challenges.
文摘Road pavements in tunnels are usually made of asphalt mixtures,which,unfortunately,are flammable materials.Hence,this type of pavement could release heat,and more specifically smoke,in the event of a tunnel fire,thereby worsening the environmental conditions for human health.Extensive research has been conducted in recent years to enhance the fire reaction of traditional asphalt mixtures for the road pavements used in tunnels.The addition of the Flame Retardants(FRs)in conventional asphalt mixtures appears to be promising.Nevertheless,the potential effects of the FRs in terms of the reduction in consequences on tunnel users in the event of a large fire do not seem to have been sufficiently investigated by using fluid dynamics analysis as a computational tool.Given this gap of knowledge,this article aims to quantitatively evaluate whether the use of flame-retarded asphalt mixtures,as opposed to traditional ones without FRs,might mitigate the adverse effects on the safety of evacuees and fire brigade by performing numerical analyses in the case of a tunnel fire.To achieve this goal,3D Computational Fluid Dynamics(CFD)models,which were executed using the Fire Dynamics Simulator(FDS)tool,were established in the case of a major fire of a Heavy Goods Vehicle(HGV)characterized by a maximum Heat Release Rate(HRRmax)of 100 MW.The people evacuation process was also simulated,and the Evac tool was used.Compared to the traditional asphalt pavements without FRs,the simulation findings indicated that the addition of the FRs causes a reduction in CO and CO_(2)levels in the tunnel during the aforementioned fire,with a minor number of evacuees being exposed to the risk of incapacity to self-evacuate,as well as certain safety benefits for the operability of the firefighters entering the tunnel downstream of the fire when the tunnel is naturally ventilated.
基金financially supported by the National Natural Science Foundation of China(Nos.92372122 and 52471242)the Fundamental Research Funds for the Central Universities,China(Nos.GG2060127001,KY2060000150,and WK2060000040)supported by the Joint Laboratory for USTC and Yanchang Petroleum,China(No.2022ZK-03)。
文摘Along with the surging demand for energy storage devices,the cost and availability of the materials remain dominant factors in slowing down their industrial application.The repurposing of waste asphalt into high-performance electrode materials is of significant interest,as it holds the potential to circumvent energy and environmental issues.Here,we report the controllable synthesis of asphalt-derived mesoporous carbon as an active material for electrocatalytic hydrogen gas capacitor(EHGC).The hierarchically porous carbon(HPC)with a high surface area of 1943.4 m^(2)·g^(-1)can operate in pH universal aqueous electrolytes in EHGC.It displays a specific energy and power density of 57 Wh·kg^(-1)and 554 W·kg^(-1)in neutral electrolyte as well as 52 Wh·kg^(-1)and 657 W·kg^(-1)in acidic electrolyte.Additionally,the charge storage mechanism of HPC-EHGC is studied with the help of Raman spectroscopy and X-ray photoelectron spectroscopy.Furthermore,the assembled HPC-EHGC device displays a discharge capacitance of 170 F·g^(-1)with an excellent capacitance retention rate of 100%up to 20000 cycles at 10 A·g^(-1)in acidic electrolyte.This work introduces a novel approach to converting waste asphalt into high-performance carbon for EHGC,achieving superior performance over commercial materials.By simultaneously addressing environmental waste issues and advancing energy storage technology,this study makes a significant contribution to sustainable materials science and next-generation battery development.
文摘The elevated temperatures adversely affect the durability and lifespan of pavement.Understanding the factors that influence asphalt pavement temperature offers valuable insights for creating climate-friendly cities with cooler pavement surfaces.In this study,three aggregates of varying types and colors,two types of bitumen(one without pigment and one with the addition of red pigment,Fe2O3),and two levels of mean texture depth(MTD),high and low,were utilized to create asphalt samples using Marshall's method.A total of 38 thermocouple sensors were employed to simultaneously record temperatures in three areas within the samples,as well as the temperatures in shaded and sunlit conditions over a period of 17 days.Furthermore,a comprehensive evaluation was conducted to assess the impact of each factor on the solar reflectance index(SRI).Twelve general linear models(GLMs)were developed using a full factorial design of experiment,and five models with an R2 greater than 95%were evaluated and analyzed.The analysis,based on the coefficients derived from the GLMs,indicates that the mean MTD is the most significant parameter affecting surface temperature.Pigment color emerged as the second most influential factor affecting both surface and bottom temperatures.Additionally,the findings revealed that MTD has the greatest impact on the SRI,followed by pigment color and aggregate color.It was also determined that the interaction between density,pigment color,and aggregate color plays a crucial role in determining the temperatures of both the surface and bottom of the specimens.
