A new way to improve the tunnel fire protection by using flame-retarded porous asphalt pavement containing ATH powders was introduced. Based on the miniature burning test designed and conducted, the burning time and t...A new way to improve the tunnel fire protection by using flame-retarded porous asphalt pavement containing ATH powders was introduced. Based on the miniature burning test designed and conducted, the burning time and temperature of porous asphalt （PA） and flame-retarded porous asphalt （FRPA） were studied comparing with cement concrete pavement, dense-graded lIMA and SMA. Results of burning test and pavement performance test indicate that FRPA is appropriate and suitable as the pavement material of highway tunnel.展开更多
Used as flame returdant of tunnel asphalt pavement, organic bromides produce a large amount of poisons and smoke in construction and flame retardation stage. The alkaline filler was found to replace mineral filler, ...Used as flame returdant of tunnel asphalt pavement, organic bromides produce a large amount of poisons and smoke in construction and flame retardation stage. The alkaline filler was found to replace mineral filler, and the flame- retarded asphalt mixtures were produced. Experimental results show that these asphalt mixtures are smoke restrained ; the performances and construction technology of asphalt pavement are not influenced; also the alkaline filler is of low-price. So this kind of flame-retarded asphalt mixtures is suitable for tunnel patement.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
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
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
Poor formability is a key problem that limits the application of flame-retardant Mg-Al-Ca based alloys at room temperature.In this study,we present a new Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy which exhibits excellent flame-r...Poor formability is a key problem that limits the application of flame-retardant Mg-Al-Ca based alloys at room temperature.In this study,we present a new Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy which exhibits excellent flame-retardant performance and excellent formability.Due to the high Ca content,the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy does not burn at 1065℃.The formability of the alloys is measured using a three-point bending test,and the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy shows excellent formability,with a significant increase in bending displacement from 7.1 mm to 23.8 mm compared to the Mg-6Al-3Ca-0.4Mn(wt%)alloy.The combined effect of the weakened basal texture,the reduction of twins and the plastically deformable Al2Ca phase particles ensures good formability of the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy.The dynamic recrystallization mechanisms of the alloys have been analyzed,and the promotion of dynamic recrystallization by the PSN mechanism is responsible for the weakened basal texture and the reduction of twins in the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy.The new Mg alloy is attractive for industrial applications due to its excellent flame-retardant performance and formability.展开更多
The alternating copolymer of CO_(2) with epoxide is a green plastic that can efficiently transform CO_(2) into valuable chemicals. Despite the significant advances made, the restricted practical application of CO_(2)-...The alternating copolymer of CO_(2) with epoxide is a green plastic that can efficiently transform CO_(2) into valuable chemicals. Despite the significant advances made, the restricted practical application of CO_(2)-sourced polycarbonates due to their lack of functionality has hindered field development. We successfully demonstrated the flame retardancy of poly(chloropropylene carbonate) (PCPC), a perfectly alternating copolymer of epichlorohydrin (ECH) and CO_(2). This was prepared at a 200-gram scale using a high-efficacy tetranuclear organoborane catalyst. PCPC’s excellent flame-retardant performance has been proven by both the vertical combustion test (UL94 V-0) and the limiting oxygen index (LOI) value (29.1%). The underlaid flame-retardant mechanism of PCPC was clearly elucidated. As a result, we confirmed that the generated cyclic carbonates and concurrently released flame-retardant chlorine radicals, hydrogen chloride, and CO_(2) during combustion render PCPC an excellent flame retardant. Furthermore, we investigated the practicability of PCPC as a halogen-rich polymeric flame retardant by blending it with commercial bisphenol A polycarbonate (BPA-PC). PCPC upgraded the flame retardancy rating of BPA polycarbonate from V-2 to V-0 even with a mere 1 wt% addition. It is our hope that this result will prove useful in future developments of advanced CO_(2)-sourced polymeric materials.展开更多
Aluminum industrial solid waste represents a highly abundant yet underutilized resource.Its incorporation into asphalt pavement applications can effectively reduce the exploitation of natural resources and mitigate en...Aluminum industrial solid waste represents a highly abundant yet underutilized resource.Its incorporation into asphalt pavement applications can effectively reduce the exploitation of natural resources and mitigate environmental issues caused by waste accumulation.This paper focuses on typical solid waste resources generated by the aluminum industry,summarizing the latest research progress in their application within the asphalt pavement industry and proposing key directions for future attention.The physicochemical properties of red mud(RM),spent aluminum electrolytic cathode materials,and secondary aluminum dross(SAD)are reviewed.The effects and mechanisms of RM,spent aluminum electrolytic cathode materials,and SAD on the performance of asphalt and its mixtures are elaborated.RM significantly enhances the aging resistance of asphalt,the hightemperature rheological properties of asphalt mastic,and the rutting resistance of asphalt mixtures.Spent aluminum electrolytic cathode materials require the removal of fluorides and cyanides before further application in asphalt pavement.SAD effectively improves the dynamic stability of asphalt mixtures.This review presents the first systematic summary of key scientific challenges and technical bottlenecks in the application of aluminum industrial solid waste in asphalt pavements.It clarifies that future research should prioritize waste pretreatment technologies,performance regulation mechanisms,and life cycle environmental impact assessments.These contributions provide essential theoretical foundations and technical guidance for advancing the resource utilization of aluminum industrial solid waste,holding substantial significance for promoting the development of green transportation infrastructure.展开更多
The effect of extrusion temperature on the dynamic recrystallization behavior and mechanical properties of the flame-retardant Mg−6Al−3Ca−1Zn−1Sn−Mn(wt.%)alloy was investigated.The observed dynamic recrystallization m...The effect of extrusion temperature on the dynamic recrystallization behavior and mechanical properties of the flame-retardant Mg−6Al−3Ca−1Zn−1Sn−Mn(wt.%)alloy was investigated.The observed dynamic recrystallization mechanisms in the alloy include continuous dynamic recrystallization(CDRX)and particle simulated nucleation(PSN)during hot extrusion.A significant increase in yield strength,from 218 to 358 MPa,representing a 140 MPa increase,is achieved by decreasing the extrusion temperature.The strengthening mechanisms were analyzed quantitatively,with the enhanced strength primarily attributed to grain boundary and dislocation strengthening.The plasticity mechanism was analyzed qualitatively,and the increase in the volume fraction of unDRXed grains caused by the decrease in extrusion temperature leads to an increase in the number of{1012}tensile twins during the tensile deformation,resulting in a reduction in plasticity.展开更多
Single ion gel polymer electrolyte has the advantages of high Li^(+)conductivity and dendrite mitigation.However,the addition of organic solvent makes the electrolyte flammable,posing serious safety hazards.Herein,we ...Single ion gel polymer electrolyte has the advantages of high Li^(+)conductivity and dendrite mitigation.However,the addition of organic solvent makes the electrolyte flammable,posing serious safety hazards.Herein,we report a flame-retard ant cross-linked sp^(3)boron-based single-ion gel polymer electrolyte(BSIPE).BSIPE was prepared by a simple one-step photoinitiated in situ thiol-ene click reaction.Due to the boron-based anions being immobilized in the cross-linking network,the developed BSIPE/PFN exhibits a high t_(Li^(+))(0.87),which can mitigate concentration polarization phenomenon and suppress the growth of lithium dendrites.BSIPE/PFN plasticized with triethyl phosphate(TEP),fluoroethylene carbonate(FEC)and LiNO_(3)exhibits enhanced ionic conductivity of 4.25×10^(-4)S cm^(-1)at 30℃ and flame retardancy.FEC and LiNO_(3) are conducive to form a stable solid electrolyte interphase(SEI)rich in Li_(3)N and LiF to improve interface stability.As expected,the dendrite-free Li‖BSIPE/PFN‖Li symmetric cell exhibits considerable cycling life over 1500 h.BSIPE/PFN significantly boosts the performance of LFP‖Li cell,which displays a capacity retention of 84.6%after 500 cycles.The BSIPE/PFN has promising applications in highsafety and high-performance lithium metal batteries.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
Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,p...Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,phosphorous-containing 1-vinylimidazole salts(called VIDHP and VIDPP)were synthesized through the facile neutralization of the acid and 1-vinylimidazole.VIDHP and VIDPP were then applied as flame-retardant crosslinking agents of VERs,by which phosphorus-containing groups could be incorporated into the resin chain via ionic bonds.VIDHP/VER and VIDPP/VER showed a high curing activity and can be well cured in moderate temperatures.With 20 wt.%additions of VIDHP and VIDPP,VIDHP20/VER,and VIDPP20/VER presented a limiting oxygen index value of 29.7%and 28.4%,respectively,with the latter achieving a UL 94 V0 rating.In the cone calorimetric test,compared to the unmodified VERs,VIDPP20/VER exhibited large reductions in the peak heat release rate,total heat release rate,and total smoke release rate while VIDHP20/VER demonstrated comparatively inferior performance in terms of the heat release.VIDHP20/VER and VIDPP20/VER showed good thermal stability and presented a little lower glass transition temperature than the control sample.VIDPP with a low phosphorus oxidation state(+1)demonstrated high flame-retardant activities in the gaseous phase,whereas VIDHP with a high phosphorus oxidation state(+5)primarily exhibited efficacy in the condensed phase.展开更多
This paper presents a comprehensive review of previous research based on scientific papers,technical reports,and published academic theses.The review focuses on studies and investigations concerning the application of...This paper presents a comprehensive review of previous research based on scientific papers,technical reports,and published academic theses.The review focuses on studies and investigations concerning the application of rubberbased biopolymers as modifiers in asphalt binders and mixtures,alongside relevant existing literature,encompassing their influence on asphalt binders and mixtures as well as their binder-aggregate interface performance.Incorporating rubber-based biopolymers into base asphalt significantly enhances the viscosity,complex modulus,rutting parameters,and recovery percentage while reducing non-recoverable compliance and phase angle.These alterations indicate that rubber-based biopolymer-modified asphalt displays superior resistance to permanent deformation,surpassing base asphalt's linear and non-linear rheological properties.Besides,rubber-based biopolymers alter the functional groups within the base asphalt due to the interaction in the asphalt matrix,especially afterthe aging process.These biopolymers are uniformly dispersed throughoutthe asphalt matrix,facilitated by the interconnected elastic networks among the biopolymer molecules.This improves the rheological and mechanical properties of both asphalt binders and mixtures.It is recommended that further studies investigate the combined effects of rubber-based biopolymers with other materials commonly used in asphalt modifications,such as nanomaterials and biomaterials,on the non-linear rheological and microstructural properties of asphalt binders,as well asthe performance of asphalt mixtures.Advanced simulation and modeling techniques,such as molecular dynamic simulation and machine learning should be employed to understand the behavior of rubber-based biopolymermodified asphalt binders and mixtures in various aging and loading situations.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
Severe segregation and poor rheological properties in crumb rubber(CR)modified asphalt(CRMT)were addressed by investigating the performance improvement effect of organic expanded vermiculite(OEV)as a comodifier,while ...Severe segregation and poor rheological properties in crumb rubber(CR)modified asphalt(CRMT)were addressed by investigating the performance improvement effect of organic expanded vermiculite(OEV)as a comodifier,while the modification mechanism of the resulting asphalt was also elucidated.Vermiculite was thermally treated and chemically modified to enhance its interaction with the asphalt matrix and CR,improving dispersion and interfacial properties.CR/OEV/furfural extract oil(OIL)composite modified asphalt(COMT)was prepared in this study.The compatibility and microscopic mechanism of modified asphalt were characterized by dynamic shear rheological test,multiple stress creep recovery(MSCR)test,BBR test,thermal segregation test,fluorescent scanning test,infrared spectroscopy,and gel permeation chromatography.Rheological tests showed that the modified asphalt exhibited improved high-temperature stability,with increased G*/sin(δ)values,and better low-temperature flexibility.Storage stability tests showed a reduced softening point difference,indicating enhanced homogeneity and reduced segregation.Microscopic analysis revealed that OEV effectively optimized the microstructure of the composite system by promoting the uniform dispersion of CR within the asphalt matrix.Furthermore,the macromolecular weight of COMT was increased by 31.9%,molecular weight analysis confirmed a higher proportion of large molecular weight fractions,contributing to enhanced rheological properties and compatibility.These findings demonstrated that OEV significantly improved the performance and durability of CRMT,providing a promising approach for sustainable road construction.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
基金Hi-tech Research and Development Program of China (863 Program of China) (No.2006AA11Z117)
文摘A new way to improve the tunnel fire protection by using flame-retarded porous asphalt pavement containing ATH powders was introduced. Based on the miniature burning test designed and conducted, the burning time and temperature of porous asphalt （PA） and flame-retarded porous asphalt （FRPA） were studied comparing with cement concrete pavement, dense-graded lIMA and SMA. Results of burning test and pavement performance test indicate that FRPA is appropriate and suitable as the pavement material of highway tunnel.
文摘Used as flame returdant of tunnel asphalt pavement, organic bromides produce a large amount of poisons and smoke in construction and flame retardation stage. The alkaline filler was found to replace mineral filler, and the flame- retarded asphalt mixtures were produced. Experimental results show that these asphalt mixtures are smoke restrained ; the performances and construction technology of asphalt pavement are not influenced; also the alkaline filler is of low-price. So this kind of flame-retarded asphalt mixtures is suitable for tunnel patement.
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supported by the National Key Research and Development Program of China(No.2021YFB3701100)the Applied Basic Research Program Project of Liaoning Province of China(No.2023020253-JH2/1016)the Key Research and Development Plan of Shanxi Province(No.202102050201005)。
文摘Poor formability is a key problem that limits the application of flame-retardant Mg-Al-Ca based alloys at room temperature.In this study,we present a new Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy which exhibits excellent flame-retardant performance and excellent formability.Due to the high Ca content,the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy does not burn at 1065℃.The formability of the alloys is measured using a three-point bending test,and the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy shows excellent formability,with a significant increase in bending displacement from 7.1 mm to 23.8 mm compared to the Mg-6Al-3Ca-0.4Mn(wt%)alloy.The combined effect of the weakened basal texture,the reduction of twins and the plastically deformable Al2Ca phase particles ensures good formability of the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy.The dynamic recrystallization mechanisms of the alloys have been analyzed,and the promotion of dynamic recrystallization by the PSN mechanism is responsible for the weakened basal texture and the reduction of twins in the Mg-6Al-3Ca-0.4Mn-2Zn(wt%)alloy.The new Mg alloy is attractive for industrial applications due to its excellent flame-retardant performance and formability.
基金supported by the National Science Fund for Distinguished Young Scholars(No.T2225004)National Natural Science Foundation of China(No.52373092)Shccig-Qinling Program.
文摘The alternating copolymer of CO_(2) with epoxide is a green plastic that can efficiently transform CO_(2) into valuable chemicals. Despite the significant advances made, the restricted practical application of CO_(2)-sourced polycarbonates due to their lack of functionality has hindered field development. We successfully demonstrated the flame retardancy of poly(chloropropylene carbonate) (PCPC), a perfectly alternating copolymer of epichlorohydrin (ECH) and CO_(2). This was prepared at a 200-gram scale using a high-efficacy tetranuclear organoborane catalyst. PCPC’s excellent flame-retardant performance has been proven by both the vertical combustion test (UL94 V-0) and the limiting oxygen index (LOI) value (29.1%). The underlaid flame-retardant mechanism of PCPC was clearly elucidated. As a result, we confirmed that the generated cyclic carbonates and concurrently released flame-retardant chlorine radicals, hydrogen chloride, and CO_(2) during combustion render PCPC an excellent flame retardant. Furthermore, we investigated the practicability of PCPC as a halogen-rich polymeric flame retardant by blending it with commercial bisphenol A polycarbonate (BPA-PC). PCPC upgraded the flame retardancy rating of BPA polycarbonate from V-2 to V-0 even with a mere 1 wt% addition. It is our hope that this result will prove useful in future developments of advanced CO_(2)-sourced polymeric materials.
基金supported by the National Natural Science Foundation of China(No.52368058)Guangxi Science and Technology Program(Gui Ke AB23026067).
文摘Aluminum industrial solid waste represents a highly abundant yet underutilized resource.Its incorporation into asphalt pavement applications can effectively reduce the exploitation of natural resources and mitigate environmental issues caused by waste accumulation.This paper focuses on typical solid waste resources generated by the aluminum industry,summarizing the latest research progress in their application within the asphalt pavement industry and proposing key directions for future attention.The physicochemical properties of red mud(RM),spent aluminum electrolytic cathode materials,and secondary aluminum dross(SAD)are reviewed.The effects and mechanisms of RM,spent aluminum electrolytic cathode materials,and SAD on the performance of asphalt and its mixtures are elaborated.RM significantly enhances the aging resistance of asphalt,the hightemperature rheological properties of asphalt mastic,and the rutting resistance of asphalt mixtures.Spent aluminum electrolytic cathode materials require the removal of fluorides and cyanides before further application in asphalt pavement.SAD effectively improves the dynamic stability of asphalt mixtures.This review presents the first systematic summary of key scientific challenges and technical bottlenecks in the application of aluminum industrial solid waste in asphalt pavements.It clarifies that future research should prioritize waste pretreatment technologies,performance regulation mechanisms,and life cycle environmental impact assessments.These contributions provide essential theoretical foundations and technical guidance for advancing the resource utilization of aluminum industrial solid waste,holding substantial significance for promoting the development of green transportation infrastructure.
基金supported by the National Key Research and Development Program of China(No.2021YFB3701100)the Applied Basic Research Program Project of Liaoning Province,China(No.2023020253-JH2/1016)the Key Research and Development Plan of Shanxi Province,China(No.202102050201005).
文摘The effect of extrusion temperature on the dynamic recrystallization behavior and mechanical properties of the flame-retardant Mg−6Al−3Ca−1Zn−1Sn−Mn(wt.%)alloy was investigated.The observed dynamic recrystallization mechanisms in the alloy include continuous dynamic recrystallization(CDRX)and particle simulated nucleation(PSN)during hot extrusion.A significant increase in yield strength,from 218 to 358 MPa,representing a 140 MPa increase,is achieved by decreasing the extrusion temperature.The strengthening mechanisms were analyzed quantitatively,with the enhanced strength primarily attributed to grain boundary and dislocation strengthening.The plasticity mechanism was analyzed qualitatively,and the increase in the volume fraction of unDRXed grains caused by the decrease in extrusion temperature leads to an increase in the number of{1012}tensile twins during the tensile deformation,resulting in a reduction in plasticity.
基金supported by the National Natural Science Foundation of China(22179149,22075329,51573215,and 21978332)Research and Development Project of Henan Academy Sciences China(232018002)。
文摘Single ion gel polymer electrolyte has the advantages of high Li^(+)conductivity and dendrite mitigation.However,the addition of organic solvent makes the electrolyte flammable,posing serious safety hazards.Herein,we report a flame-retard ant cross-linked sp^(3)boron-based single-ion gel polymer electrolyte(BSIPE).BSIPE was prepared by a simple one-step photoinitiated in situ thiol-ene click reaction.Due to the boron-based anions being immobilized in the cross-linking network,the developed BSIPE/PFN exhibits a high t_(Li^(+))(0.87),which can mitigate concentration polarization phenomenon and suppress the growth of lithium dendrites.BSIPE/PFN plasticized with triethyl phosphate(TEP),fluoroethylene carbonate(FEC)and LiNO_(3)exhibits enhanced ionic conductivity of 4.25×10^(-4)S cm^(-1)at 30℃ and flame retardancy.FEC and LiNO_(3) are conducive to form a stable solid electrolyte interphase(SEI)rich in Li_(3)N and LiF to improve interface stability.As expected,the dendrite-free Li‖BSIPE/PFN‖Li symmetric cell exhibits considerable cycling life over 1500 h.BSIPE/PFN significantly boosts the performance of LFP‖Li cell,which displays a capacity retention of 84.6%after 500 cycles.The BSIPE/PFN has promising applications in highsafety and high-performance lithium metal batteries.
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supported by the National Natural Science Foundation of China(Grant Nos.51991351 and51903132)the Young Elite Scientist Sponsorship Program by CAST(No.2022QNRC001).
文摘Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,phosphorous-containing 1-vinylimidazole salts(called VIDHP and VIDPP)were synthesized through the facile neutralization of the acid and 1-vinylimidazole.VIDHP and VIDPP were then applied as flame-retardant crosslinking agents of VERs,by which phosphorus-containing groups could be incorporated into the resin chain via ionic bonds.VIDHP/VER and VIDPP/VER showed a high curing activity and can be well cured in moderate temperatures.With 20 wt.%additions of VIDHP and VIDPP,VIDHP20/VER,and VIDPP20/VER presented a limiting oxygen index value of 29.7%and 28.4%,respectively,with the latter achieving a UL 94 V0 rating.In the cone calorimetric test,compared to the unmodified VERs,VIDPP20/VER exhibited large reductions in the peak heat release rate,total heat release rate,and total smoke release rate while VIDHP20/VER demonstrated comparatively inferior performance in terms of the heat release.VIDHP20/VER and VIDPP20/VER showed good thermal stability and presented a little lower glass transition temperature than the control sample.VIDPP with a low phosphorus oxidation state(+1)demonstrated high flame-retardant activities in the gaseous phase,whereas VIDHP with a high phosphorus oxidation state(+5)primarily exhibited efficacy in the condensed phase.
基金the Ministry of Higher Education Malaysia for providing the Fundamental Research Grant Scheme with Project Code FRGS/1/2021/TK01/USM/02/1,which facilitated the execution of this researchThe authors also appreciate the support from Universiti Sains Malaysia through the Research University Individual(RUI)Grant(1001.PAWAM.8014140).
文摘This paper presents a comprehensive review of previous research based on scientific papers,technical reports,and published academic theses.The review focuses on studies and investigations concerning the application of rubberbased biopolymers as modifiers in asphalt binders and mixtures,alongside relevant existing literature,encompassing their influence on asphalt binders and mixtures as well as their binder-aggregate interface performance.Incorporating rubber-based biopolymers into base asphalt significantly enhances the viscosity,complex modulus,rutting parameters,and recovery percentage while reducing non-recoverable compliance and phase angle.These alterations indicate that rubber-based biopolymer-modified asphalt displays superior resistance to permanent deformation,surpassing base asphalt's linear and non-linear rheological properties.Besides,rubber-based biopolymers alter the functional groups within the base asphalt due to the interaction in the asphalt matrix,especially afterthe aging process.These biopolymers are uniformly dispersed throughoutthe asphalt matrix,facilitated by the interconnected elastic networks among the biopolymer molecules.This improves the rheological and mechanical properties of both asphalt binders and mixtures.It is recommended that further studies investigate the combined effects of rubber-based biopolymers with other materials commonly used in asphalt modifications,such as nanomaterials and biomaterials,on the non-linear rheological and microstructural properties of asphalt binders,as well asthe performance of asphalt mixtures.Advanced simulation and modeling techniques,such as molecular dynamic simulation and machine learning should be employed to understand the behavior of rubber-based biopolymermodified asphalt binders and mixtures in various aging and loading situations.
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supported by National Key R&D Program of China(2024YFF0510200)National Natural Science Foundation of China(52478438,52174237)+2 种基金Excellent Early Career Scientists form Germany(GZ1717)Science and Technology Project of Changsha-Outstanding Innovative Youth(kq2406007)Practice Innovation and Entrepreneurship Enhancement Program for Postgraduate of Changsha University of Science&Technology(CLSJCX24006).
文摘Severe segregation and poor rheological properties in crumb rubber(CR)modified asphalt(CRMT)were addressed by investigating the performance improvement effect of organic expanded vermiculite(OEV)as a comodifier,while the modification mechanism of the resulting asphalt was also elucidated.Vermiculite was thermally treated and chemically modified to enhance its interaction with the asphalt matrix and CR,improving dispersion and interfacial properties.CR/OEV/furfural extract oil(OIL)composite modified asphalt(COMT)was prepared in this study.The compatibility and microscopic mechanism of modified asphalt were characterized by dynamic shear rheological test,multiple stress creep recovery(MSCR)test,BBR test,thermal segregation test,fluorescent scanning test,infrared spectroscopy,and gel permeation chromatography.Rheological tests showed that the modified asphalt exhibited improved high-temperature stability,with increased G*/sin(δ)values,and better low-temperature flexibility.Storage stability tests showed a reduced softening point difference,indicating enhanced homogeneity and reduced segregation.Microscopic analysis revealed that OEV effectively optimized the microstructure of the composite system by promoting the uniform dispersion of CR within the asphalt matrix.Furthermore,the macromolecular weight of COMT was increased by 31.9%,molecular weight analysis confirmed a higher proportion of large molecular weight fractions,contributing to enhanced rheological properties and compatibility.These findings demonstrated that OEV significantly improved the performance and durability of CRMT,providing a promising approach for sustainable road construction.
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.
