A simultaneous boost in toughness and fire safety of epoxy(EP)is achieved through solvent-free one-step neutralization of phytic acid with 1,8-diaminooctane to yield a multifunctional bio-based curing agent,PA-DAO.Whe...A simultaneous boost in toughness and fire safety of epoxy(EP)is achieved through solvent-free one-step neutralization of phytic acid with 1,8-diaminooctane to yield a multifunctional bio-based curing agent,PA-DAO.When used as the sole hardener,5 wt%PA-DAO increased the tensile,flexural,and impact strengths by 165%,81%,and 455%,respectively,over the parent amine system,whereas the tensile and flexural toughness increased by 1387% and 775%,respectively.At 25 wt% loading,the resin attained a UL-94 V-0 rating and a limiting oxygen index of 28.1%,accompanied by a 71% reduction in the peak heat-release rate and a 53%suppression of total smoke production.This facile,green protocol provides scalable access to ultra-tough,intrinsically flame-retardant epoxy networks without external plasticizers or additives.展开更多
The addition of high-content crumb rubber(HCCR)in asphalt can effectively address waste tire pollution and provide sustainable environmental and economic advantages.However,the practical application of conventional ru...The addition of high-content crumb rubber(HCCR)in asphalt can effectively address waste tire pollution and provide sustainable environmental and economic advantages.However,the practical application of conventional rubberized binders is significantly limited by high viscosity and poor storage stability.To address these issues,researchers have pretreated crumb rubber(CR)with oil,but high-temperature performance remains insufficient.Therefore,this study aimed to optimize the viscosity,storage stability,and rheological properties of high-content crumb rubber-modified asphalt(HCCRMA)by varying the pretreatment levels of CR and incorporating various additives,including styrene-butadiene-styrene(SBS),deoiled asphalt(DA),or recycled low-density polyethylene(RLDPE).In addition,CR was pretreated with waste cooking oil(WCO)at various ratios,pre-swelling temperatures,and times.The results show that DA exhibits excellent storage stability and lower viscosity compared with other modifiers in HCCRMA,and the 4%RLDPE with pretreated HCCR has the greatest high-temperature rutting resistance.The inclusion of RLDPE increases the stiffness and elasticity of the modified asphalt,which results in greater high-temperature performance.Additionally,the fluorescence microscopy(FM)test confirms that SBS exhibits better dispersion than other modifiers and forms a more homogeneous phase separation in the HCCRMA.All in all,this research achieved an optimal balance of storage stability and rheological properties in asphalt modified with pretreated HCCR and 6%SBS,which provides a valuable reference for performance improvement of HCCR-modified binders.展开更多
In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road perfor...In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road performance of emulsified asphalt cold recycled mixtures(ECRM),this study employed recycled asphalt pavement(RAP)and reclaimed inorganic binder stabilized aggregate(RAI)as dual recycled materials for ECRM preparation.The blending ratios of reclaimed base and surface layer mixtures significantly influence ECRM's performance,with adjusted proportions substantially improving compressive strength and dynamic modulus.Firstly,three distinct proportioning options were developed for the recycled materials.Mix designs incorporating varying RAP/RAI ratios were used to determine the optimal mix parameters:moisture content,cement dosage,and emulsified asphalt content.Subsequently,comprehensive performance evaluations were conducted through high-temperature wheel tracking tests,freeze-thaw splitting tests,uniaxial compression tests,and dynamic modulus measurements to analyze the pavement characteristics of the three ECRM formulations.Experimental results demonstrate:Compared with ECRM with a blending ratio of RAP:RAI:new aggregate=30:50:20(Option 1),the dynamic stability,freeze-thaw splitting strength ratio,compressive strength,and compressive resilient modulus of ECRM under Option 3(RAP:RAI:new aggregate=50:30:20)decreased by 31.8%,5.2%,16.4%,and 13.1%,respectively.This indicates that increasing RAP content while reducing RAI proportion enhances the tensile strength of ECRM,yet adversely affects its high-temperature stability,moisture resistance,and compressive performance.This work not only addresses the challenge of jointly utilizing asphalt pavement waste and base waste,but also provides a cost-effective and sustainable method for the stable application of milling material resources in road engineering.展开更多
Dynamic thermal mechanical analysis was used to evaluate the viscoelasticity of asphalt.The parameters included the energy storage modulus(E),the loss modulus(E'),and the loss tangent(tanδ).The impact of three ki...Dynamic thermal mechanical analysis was used to evaluate the viscoelasticity of asphalt.The parameters included the energy storage modulus(E),the loss modulus(E'),and the loss tangent(tanδ).The impact of three kinds of particles containing CaCO_(3)with different size and structure on the mechanical properties was also measured.The addition of limestone increases the glass transition temperature,while nanoCaCO_(3)@SiO_(2)decreases the glass transition temperature.Nano-CaCO_(3)has a negligible effect on the glass transition temperature.The particle size of the limestone is 0.075 mm,which is a material at the micrometer level.During the heating process,it hinders the molecular movement and makes the material harder.Thus the glass transition temperature is relatively high.展开更多
To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt b...To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.展开更多
A comprehensive full-sieve-hole grading correction method was used to adjust aggregate gradings.The fatigue properties of recycled concrete aggregate(RCA)asphalt mixtures were investigated using an improved indirect t...A comprehensive full-sieve-hole grading correction method was used to adjust aggregate gradings.The fatigue properties of recycled concrete aggregate(RCA)asphalt mixtures were investigated using an improved indirect tensile fatigue test under temperature-humidity coupling based on 20-year meteorological data of Beijing,and the degeneration mechanism was further explored by scanning electron microscopy and energy-dispersive spectroscopy.The experimental results indicate that replacing 5-20 mm coarse limestone aggregate(LA)with RCA at a 50% substitution volume can mitigate the impact of RCA variations on the asphalt mixture proportioning design.All RCA asphalt mixtures have lower initial fatigue properties than the LA asphalt mixture.However,under temperature-humidity coupling,the long-term fatigue property of an RCA asphalt mixture with a low proportion of recycled brick exceeds that of the LA asphalt mixture,and the fatigue life decline rate of the RCA asphalt mixture during 10-year service decreases by approximately 25%.This is due to the penetration of the asphalt mortar into the RCA through the pores and cracks on the RCA surface.It forms an interfacial transition zone composed of asphalt mortar and cement mortar and further reduces the mixture damage caused by the water and freeze-thaw conditions.展开更多
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
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
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
Current mix design practices typically assume total blending and use the white curve of reclaimed asphalt pavement(RAP)to determine the gradation and optimum asphalt content(OAC)of recycled hot mix asphalt(HMA),often ...Current mix design practices typically assume total blending and use the white curve of reclaimed asphalt pavement(RAP)to determine the gradation and optimum asphalt content(OAC)of recycled hot mix asphalt(HMA),often overlooking the effects of RAP agglomeration and partial blending.This oversight can result in unsatisfactory performance,particularly when higher RAP content is used.Therefore,this paper reviews and discusses strategies for adjusting the mix design of recycled HMA to enhance its in-service performance.The discussion begins with RAP particle agglomeration,a significant phenomenon that significantly impacts the aggregate gradation of recycled HMA.Subsequently,detection methods to clarify the blending between virgin and RAP binders are described.Partial blending between RAP and virgin binders is common,and various indexes have been proposed to quantify the blending degree.Finally,the adjusted mix design method of recycled HMA is presented,emphasizing gradation optimization and corrected OAC.Gradation optimization should account for RAP agglomeration,while the corrected OAC should consider particle blending.Recycled HMA using the adjusted mix design exhibits improved crack resistance and fatigue life without substantially impairing rutting performance.This review aims to help both academics and highway agencies maximize the utilization of RAP materials within sustainable pavement frameworks.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
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 low lithium transference number of conventional dual-ion polymer electrolytes will lead to concentration polarization and lithium dendrite growth,thereby affecting the safety and cycling performance of lithium bat...The low lithium transference number of conventional dual-ion polymer electrolytes will lead to concentration polarization and lithium dendrite growth,thereby affecting the safety and cycling performance of lithium batteries.Herein,we report a flame-retardant polycarbonate-based single-ion conducting polymer electrolyte(PAGEC-B/PFN).Due to the immobilization of anions within the polycarbonate crosslinking network,PAGEC-B/PFN exhibits a high lithium transference number(0.86),which is beneficial for alleviating concentration polarization and suppressing the growth of lithium dendrite.With the assistance of the TEP flame retardant and FEC,as well as LiNO_(3) additives,PAGEC-B/PFN exhibits excellent flame retardancy,high ionic conductivity,and outstanding interfacial compatibility with the lithium metal anode.As expected,PAGEC-B/PFN achieves a high critical current density of up to 2.0 mA cm^(-2)and stable cycling of Li‖Li cell for over 2200 h.Meanwhile,LFP‖PAGEC-B/PFN‖Li cell delivers a specific capacity of 147.8 mA h g^(-1)at 0.5 C and exhibits excellent cycling performance over 600 cycles.This work provides a strategy for designing solid-state lithium batteries with high safety and high performance.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
基金financially supported by Zhejiang Provincial"Leading Force"and"Leading Bird"R&D Key Project(No.2022C03128)Basic Public Welfare Research Plan of Zhejiang Province(No.LY21C160003)+1 种基金National Natural Science Foundation(No.51991355)Zhejiang A&F University Scientific Research Start-up Fund(No.2023LFR134)。
文摘A simultaneous boost in toughness and fire safety of epoxy(EP)is achieved through solvent-free one-step neutralization of phytic acid with 1,8-diaminooctane to yield a multifunctional bio-based curing agent,PA-DAO.When used as the sole hardener,5 wt%PA-DAO increased the tensile,flexural,and impact strengths by 165%,81%,and 455%,respectively,over the parent amine system,whereas the tensile and flexural toughness increased by 1387% and 775%,respectively.At 25 wt% loading,the resin attained a UL-94 V-0 rating and a limiting oxygen index of 28.1%,accompanied by a 71% reduction in the peak heat-release rate and a 53%suppression of total smoke production.This facile,green protocol provides scalable access to ultra-tough,intrinsically flame-retardant epoxy networks without external plasticizers or additives.
基金supported by the Transportation Science and Technology Program of Henan Province(grant number:2023-4-2)the Key Research and Development Program of Ningxia Science and Technology Department(grant number:2022BEG02008)+2 种基金China Communications Construction Group Co.,Ltd.Science and Technology R&D Project(grant number:2021KJW02)the Research and Development Program of Henan Transportation Investment Group Co.,Ltd.(grant number:HNJT2025-1-9)the Postdoctoral Fellowship Program of CPSF(grand number:GZC20251139).
文摘The addition of high-content crumb rubber(HCCR)in asphalt can effectively address waste tire pollution and provide sustainable environmental and economic advantages.However,the practical application of conventional rubberized binders is significantly limited by high viscosity and poor storage stability.To address these issues,researchers have pretreated crumb rubber(CR)with oil,but high-temperature performance remains insufficient.Therefore,this study aimed to optimize the viscosity,storage stability,and rheological properties of high-content crumb rubber-modified asphalt(HCCRMA)by varying the pretreatment levels of CR and incorporating various additives,including styrene-butadiene-styrene(SBS),deoiled asphalt(DA),or recycled low-density polyethylene(RLDPE).In addition,CR was pretreated with waste cooking oil(WCO)at various ratios,pre-swelling temperatures,and times.The results show that DA exhibits excellent storage stability and lower viscosity compared with other modifiers in HCCRMA,and the 4%RLDPE with pretreated HCCR has the greatest high-temperature rutting resistance.The inclusion of RLDPE increases the stiffness and elasticity of the modified asphalt,which results in greater high-temperature performance.Additionally,the fluorescence microscopy(FM)test confirms that SBS exhibits better dispersion than other modifiers and forms a more homogeneous phase separation in the HCCRMA.All in all,this research achieved an optimal balance of storage stability and rheological properties in asphalt modified with pretreated HCCR and 6%SBS,which provides a valuable reference for performance improvement of HCCR-modified binders.
基金sponsored by National Natural Science Foundation of China(No.52308466)SASAC Science and Technology Innovation Project(JF-23-01-0063)Shaanxi Provincial Transportation Research Project(25-84 K,25-85 K).
文摘In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road performance of emulsified asphalt cold recycled mixtures(ECRM),this study employed recycled asphalt pavement(RAP)and reclaimed inorganic binder stabilized aggregate(RAI)as dual recycled materials for ECRM preparation.The blending ratios of reclaimed base and surface layer mixtures significantly influence ECRM's performance,with adjusted proportions substantially improving compressive strength and dynamic modulus.Firstly,three distinct proportioning options were developed for the recycled materials.Mix designs incorporating varying RAP/RAI ratios were used to determine the optimal mix parameters:moisture content,cement dosage,and emulsified asphalt content.Subsequently,comprehensive performance evaluations were conducted through high-temperature wheel tracking tests,freeze-thaw splitting tests,uniaxial compression tests,and dynamic modulus measurements to analyze the pavement characteristics of the three ECRM formulations.Experimental results demonstrate:Compared with ECRM with a blending ratio of RAP:RAI:new aggregate=30:50:20(Option 1),the dynamic stability,freeze-thaw splitting strength ratio,compressive strength,and compressive resilient modulus of ECRM under Option 3(RAP:RAI:new aggregate=50:30:20)decreased by 31.8%,5.2%,16.4%,and 13.1%,respectively.This indicates that increasing RAP content while reducing RAI proportion enhances the tensile strength of ECRM,yet adversely affects its high-temperature stability,moisture resistance,and compressive performance.This work not only addresses the challenge of jointly utilizing asphalt pavement waste and base waste,but also provides a cost-effective and sustainable method for the stable application of milling material resources in road engineering.
基金Funded by National Natural Science Foundation of China(No.52472033)。
文摘Dynamic thermal mechanical analysis was used to evaluate the viscoelasticity of asphalt.The parameters included the energy storage modulus(E),the loss modulus(E'),and the loss tangent(tanδ).The impact of three kinds of particles containing CaCO_(3)with different size and structure on the mechanical properties was also measured.The addition of limestone increases the glass transition temperature,while nanoCaCO_(3)@SiO_(2)decreases the glass transition temperature.Nano-CaCO_(3)has a negligible effect on the glass transition temperature.The particle size of the limestone is 0.075 mm,which is a material at the micrometer level.During the heating process,it hinders the molecular movement and makes the material harder.Thus the glass transition temperature is relatively high.
基金Funded by the National Natural Science Foundation of China(No.52278446)。
文摘To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.
基金Funded by"Green Construction and Maintenance of Road Engineering"the Belt and Road Joint Laboratory,International(Hong Kong,Macao and Taiwan)Science and Technology Cooperation Project(No.Z251100007125040)the National Key R&D Program of China(No.2022YFC3803403)+3 种基金the Project of Construction and Support for High-level Innovative Teams of Beijing Municipal Institutions(No.BPHR20220109)the Cultivation Project Funds for Beijing University of Civil Engineering and Architecture(No.X24013)the BUCEA Doctor Graduate Scientific Research Ability Improvement Project(No.DG2024016)the China Scholarship Council(No.202408110091)。
文摘A comprehensive full-sieve-hole grading correction method was used to adjust aggregate gradings.The fatigue properties of recycled concrete aggregate(RCA)asphalt mixtures were investigated using an improved indirect tensile fatigue test under temperature-humidity coupling based on 20-year meteorological data of Beijing,and the degeneration mechanism was further explored by scanning electron microscopy and energy-dispersive spectroscopy.The experimental results indicate that replacing 5-20 mm coarse limestone aggregate(LA)with RCA at a 50% substitution volume can mitigate the impact of RCA variations on the asphalt mixture proportioning design.All RCA asphalt mixtures have lower initial fatigue properties than the LA asphalt mixture.However,under temperature-humidity coupling,the long-term fatigue property of an RCA asphalt mixture with a low proportion of recycled brick exceeds that of the LA asphalt mixture,and the fatigue life decline rate of the RCA asphalt mixture during 10-year service decreases by approximately 25%.This is due to the penetration of the asphalt mortar into the RCA through the pores and cracks on the RCA surface.It forms an interfacial transition zone composed of asphalt mortar and cement mortar and further reduces the mixture damage caused by the water and freeze-thaw conditions.
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 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 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sponsored by the National Natural Science Foundation of China(52178420,52408476)Special subsidy from Heilongjiang Provincial People's Government(HITTY-20190028)+1 种基金Postdoctoral Fellowship Program of CPSF(GZC20242207)the Fundamental Research Funds for the Central Universities(HIT.DZJJ.2023086).
文摘Current mix design practices typically assume total blending and use the white curve of reclaimed asphalt pavement(RAP)to determine the gradation and optimum asphalt content(OAC)of recycled hot mix asphalt(HMA),often overlooking the effects of RAP agglomeration and partial blending.This oversight can result in unsatisfactory performance,particularly when higher RAP content is used.Therefore,this paper reviews and discusses strategies for adjusting the mix design of recycled HMA to enhance its in-service performance.The discussion begins with RAP particle agglomeration,a significant phenomenon that significantly impacts the aggregate gradation of recycled HMA.Subsequently,detection methods to clarify the blending between virgin and RAP binders are described.Partial blending between RAP and virgin binders is common,and various indexes have been proposed to quantify the blending degree.Finally,the adjusted mix design method of recycled HMA is presented,emphasizing gradation optimization and corrected OAC.Gradation optimization should account for RAP agglomeration,while the corrected OAC should consider particle blending.Recycled HMA using the adjusted mix design exhibits improved crack resistance and fatigue life without substantially impairing rutting performance.This review aims to help both academics and highway agencies maximize the utilization of RAP materials within sustainable pavement frameworks.
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 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 Natural Science Foundation of China(22179149,22075329,51573215,and 21978332)Guangzhou Municipal Science and Technology Program(2025B01J2007,2025A03J4025,2025A03J4026)Fundamental Research Fund of Henan Academy of Sciences(232018002)。
文摘The low lithium transference number of conventional dual-ion polymer electrolytes will lead to concentration polarization and lithium dendrite growth,thereby affecting the safety and cycling performance of lithium batteries.Herein,we report a flame-retardant polycarbonate-based single-ion conducting polymer electrolyte(PAGEC-B/PFN).Due to the immobilization of anions within the polycarbonate crosslinking network,PAGEC-B/PFN exhibits a high lithium transference number(0.86),which is beneficial for alleviating concentration polarization and suppressing the growth of lithium dendrite.With the assistance of the TEP flame retardant and FEC,as well as LiNO_(3) additives,PAGEC-B/PFN exhibits excellent flame retardancy,high ionic conductivity,and outstanding interfacial compatibility with the lithium metal anode.As expected,PAGEC-B/PFN achieves a high critical current density of up to 2.0 mA cm^(-2)and stable cycling of Li‖Li cell for over 2200 h.Meanwhile,LFP‖PAGEC-B/PFN‖Li cell delivers a specific capacity of 147.8 mA h g^(-1)at 0.5 C and exhibits excellent cycling performance over 600 cycles.This work provides a strategy for designing solid-state lithium batteries with high safety and high performance.
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.
