Recently, researchers in the road field are focusing on the development of green asphalt materials with loweremission of volatile organic compounds (VOCs). The characterization methodology of asphalt VOCs and theinflu...Recently, researchers in the road field are focusing on the development of green asphalt materials with loweremission of volatile organic compounds (VOCs). The characterization methodology of asphalt VOCs and theinfluencing factors on VOCs release have always been the basic issue of asphalt VOCs emission reduction research.Researchers have proposed a variety of asphalt VOCs characterization methodologies, which also have mutuallyirreplaceable characteristics. Asphalt VOCs volatilization is affected by many factors. In this study, asphalt VOCscharacterization methodologies were summarized, including their advantages, disadvantages, characteristics andapplicable requirements. Subsequently, the influencing factors of VOCs release, such as asphalt types and environment conditions, are summarized to provide theoretical support for the emission reduction research. Theclassification and mechanism of newly-development asphalt VOCs emission reduction materials are reviewed. Thereduction efficiencies are also compared to select better materials and put forward the improvement objective ofnew materials and new processes. In addition, the prospects about development of VOCs release mechanism ofasphalt materials during the full life cycle and feasibility research of high-efficiency composite emission reductionmaterials in the future were put forward.展开更多
Asphalt pavement is increasingly used in paving and roofing.However,the release of volatile organic compounds(VOCs)from asphalt harm both the environment and humans.Various methods were applied to characterize the VOC...Asphalt pavement is increasingly used in paving and roofing.However,the release of volatile organic compounds(VOCs)from asphalt harm both the environment and humans.Various methods were applied to characterize the VOCs for better understanding and inhibiting.However,asphalt VOCs have huge heating temperature dependency,which makes the asphalt VOCs’characterization complicated.In this research,three kinds of heating conditions,thermal gravimetric(TG)analyzer,pyrolysis(PY)analyzer,and thermal desorber(TD),were compared to determine the temperature dependency of VOC release characteristics.Gas chromatography and mass spectrometer(GC-MS)were then coupled for VOC detection.Results indicated that the TG heating condition can surely simulate the volatilization of VOCs from some asphalt that is not in contact with air(no oxygen)during the actual construction process,while PY and TD represent the substances released by the asphalt due to the boiling point at a certain temperature and under the actual construction process,respectively.The components detected by TG heating condition are both large and small molecules,while PY and TD heating condition will detect large molecules or small molecules,respectively.The VOC composition results under various heating conditions reflect the chemical reaction law of asphalt molecules in the heating process.When heating asphalt binders to a higher temperature,macromolecular substances will gradually crack and oxidize into small molecular substances,sulfides and nitrides.With the increase of temperature,the change trend of VOC components under different conditions is different.展开更多
A new mathematical model of poro-thermoelasticity has been constructed in the context of a new consideration of heat conduction with fractional order.One-dimensional application for a poroelastic half-space saturated ...A new mathematical model of poro-thermoelasticity has been constructed in the context of a new consideration of heat conduction with fractional order.One-dimensional application for a poroelastic half-space saturated with fluid is considered.The surface of the halfspace is assumed to be traction-free,permeable,and subjected to heating.The Laplace transform technique is used to solve the problem.The inversion of the Laplace transform will be obtained numerically and the numerical values of the temperature,stresses,strains,and displacements will be illustrated graphically for the solid and the liquid.展开更多
Asphalt is a semi-solid or solid mixture formed by hydrocarbons and non-metallic elements.It is widely applied in the fields of building waterproofing and road paving.Asphalt is a low noise,durable,and renewable pavem...Asphalt is a semi-solid or solid mixture formed by hydrocarbons and non-metallic elements.It is widely applied in the fields of building waterproofing and road paving.Asphalt is a low noise,durable,and renewable pavement material.However,asphalt materials have some shortcomings such as liquefying at high temperatures and brittleness at low temperatures,which are less adaptable to different environments.Therefore,people have gradually shifted their focus to asphalt modification.This paper presents an in-depth analysis and research on the composition,structure,and performance of epoxy asphalt materials for roads,so that this material can be widely used.展开更多
To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt m...To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt material performance tester AMPT .In order to evaluate the validity of the proposed fracture test four different loading rates including 1 2 3 and 4 mm/min are examined in the AMPT. The results indicate that the fracture behavior is similar to creep at a low loading rate and does not show significant marginal tail extension at a high loading rate.It clearly shows the phase of crack initiation crack propagation and fracture at a loading rate of 3 mm/min. Besides eight fracture parameters such as fracture energy tensile strength and tensile modulus are applied to evaluate the fracture characteristics of asphalt mixture.Development of the overlay tester for the fracture test of asphalt mixture can be considered as a new fracture test of asphalt mixture.展开更多
The objective of this paper was to develop a comprehensive evaluation method and index to evaluate the performance of sealants and fillers for cracks in asphalt concrete pavements using the method of principal compone...The objective of this paper was to develop a comprehensive evaluation method and index to evaluate the performance of sealants and fillers for cracks in asphalt concrete pavements using the method of principal component analysis. The performance experiments including cone penetration, softening point, flow, resilience and tension at low temperature respectively were conducted by reference of ASTM D5329 for eight sealants and fillers often used in China. There by a principal component model was developed and weight of every index was calculated. The experimental results show that there are significantly different performances for sealants and fillers often used in China. Principal component analysis is an objective method that evaluates and selects the performance of sealants and fillers for cracks in asphalt concrete pavements.展开更多
We investigated microstructure morphologies of three asphalts（SK, Karamay, and Esso） used in China using atomic force microscopy（AFM）. The topography and phase contrast images were obtained. Topographic profile an...We investigated microstructure morphologies of three asphalts（SK, Karamay, and Esso） used in China using atomic force microscopy（AFM）. The topography and phase contrast images were obtained. Topographic profile and three dimensional images were described. Roughnesses of microstructure were calculated. And the chemical compositions of asphalt were tested to explain the microstructural mechanism of the asphalt. The results show that the topography and phase image in atomic force microscopy are appropriate to evaluate the microstructure of the asphalt binder. There are significant differences in microstructural morphologies including bee-like structure, topographic profile, 3D image, and roughness for three asphalts in this study. There are three different phases in microstructure of asphalt binder. The oil source and chemical composition of asphalt, especially asphaltenes content have a great influence on the microstructure.展开更多
The aim of this paper is to present the results of a long-term research project consisting in the elaboration of a new rational airfield pavement design procedure applied to flexible pavements. The described methodolo...The aim of this paper is to present the results of a long-term research project consisting in the elaboration of a new rational airfield pavement design procedure applied to flexible pavements. The described methodology is based on the principles and the feedback obtained from the highway pavement design process which has been applied for more than 30 years in France as well as in many other countries. Adaptations to airfield pavements have been made, including features such as accurate traffic description, consideration of lateral wander of aircrafts for instance. The results of these developments have led to a new methodology which enables optimizing pavement designs by considering various input parameters such as the type of pavement section （runway, taxiway or apron）, the material properties and the temperature. The complete description of this method is available in the new pavement design manual and it is implemented in the dedicated software Aliz6-Airfield Pavement.展开更多
This project integrates recent innovations of recycled materials used in designing and building sustainable pavements. An increasing environmental awareness and the demand for improving economic and construction effic...This project integrates recent innovations of recycled materials used in designing and building sustainable pavements. An increasing environmental awareness and the demand for improving economic and construction efficiencies, through measures such as con- struction warrantees and goals to reduce air pollution under the Kyoto Protocol, have increased the efforts to implement sustainable materials in roadways. The objective of this research is to develop a systematic approach toward selecting optimum combinations of sustainable materials for the construction of asphalt pavements. The selected materials, warm mix asphalt （WMA）, recycled asphalt shingles {RAS）I and reclaimed asphalt pave- ment {RAP） were incorporated in this study. The results of this research are intended to serve as guidelines in the selection of the mixed sustainable materials for asphalt pave- ments. The approach developed from this project draws upon previous research efforts integrating graphical modeling with optimizing the amount of sustainable materials based on the performance. With regard to moisture susceptibility and rutting potential test re- suits, as well as the MIM analysis based on a 95% confidence interval, the rutting perfor- mance and moisture susceptibility of asphalt mixtures are not significantly different regardless of the percentages of RAS, RAP, or WMA. The optimum mixture choices could be made by the plant emission rankings with consideration of the optimal WMA types, per- centages of RAS/RAP, and WMA production temperatures. The WMA mixtures prepared with 75% RAP and Advera WMA have produced the lowest CO2 emissions among the investigated mixture types.展开更多
基金the National Natural Science Foundation of China(52378460 and 51878526)the Program Fund of Non-metallic Excellent and Innovation Center for Building Materials(Grants 2024TDA-3)Knowledge Innovation Program of Wuhan-Basic Research from the Wuhan Science and Technology Bureau(2022020801010176)are gratefully acknowledged.
文摘Recently, researchers in the road field are focusing on the development of green asphalt materials with loweremission of volatile organic compounds (VOCs). The characterization methodology of asphalt VOCs and theinfluencing factors on VOCs release have always been the basic issue of asphalt VOCs emission reduction research.Researchers have proposed a variety of asphalt VOCs characterization methodologies, which also have mutuallyirreplaceable characteristics. Asphalt VOCs volatilization is affected by many factors. In this study, asphalt VOCscharacterization methodologies were summarized, including their advantages, disadvantages, characteristics andapplicable requirements. Subsequently, the influencing factors of VOCs release, such as asphalt types and environment conditions, are summarized to provide theoretical support for the emission reduction research. Theclassification and mechanism of newly-development asphalt VOCs emission reduction materials are reviewed. Thereduction efficiencies are also compared to select better materials and put forward the improvement objective ofnew materials and new processes. In addition, the prospects about development of VOCs release mechanism ofasphalt materials during the full life cycle and feasibility research of high-efficiency composite emission reductionmaterials in the future were put forward.
基金National Natural Science Foundation of China(No.51878526)for their financial supportFok Ying Tung Education Foundation for their honorary support。
文摘Asphalt pavement is increasingly used in paving and roofing.However,the release of volatile organic compounds(VOCs)from asphalt harm both the environment and humans.Various methods were applied to characterize the VOCs for better understanding and inhibiting.However,asphalt VOCs have huge heating temperature dependency,which makes the asphalt VOCs’characterization complicated.In this research,three kinds of heating conditions,thermal gravimetric(TG)analyzer,pyrolysis(PY)analyzer,and thermal desorber(TD),were compared to determine the temperature dependency of VOC release characteristics.Gas chromatography and mass spectrometer(GC-MS)were then coupled for VOC detection.Results indicated that the TG heating condition can surely simulate the volatilization of VOCs from some asphalt that is not in contact with air(no oxygen)during the actual construction process,while PY and TD represent the substances released by the asphalt due to the boiling point at a certain temperature and under the actual construction process,respectively.The components detected by TG heating condition are both large and small molecules,while PY and TD heating condition will detect large molecules or small molecules,respectively.The VOC composition results under various heating conditions reflect the chemical reaction law of asphalt molecules in the heating process.When heating asphalt binders to a higher temperature,macromolecular substances will gradually crack and oxidize into small molecular substances,sulfides and nitrides.With the increase of temperature,the change trend of VOC components under different conditions is different.
文摘A new mathematical model of poro-thermoelasticity has been constructed in the context of a new consideration of heat conduction with fractional order.One-dimensional application for a poroelastic half-space saturated with fluid is considered.The surface of the halfspace is assumed to be traction-free,permeable,and subjected to heating.The Laplace transform technique is used to solve the problem.The inversion of the Laplace transform will be obtained numerically and the numerical values of the temperature,stresses,strains,and displacements will be illustrated graphically for the solid and the liquid.
文摘Asphalt is a semi-solid or solid mixture formed by hydrocarbons and non-metallic elements.It is widely applied in the fields of building waterproofing and road paving.Asphalt is a low noise,durable,and renewable pavement material.However,asphalt materials have some shortcomings such as liquefying at high temperatures and brittleness at low temperatures,which are less adaptable to different environments.Therefore,people have gradually shifted their focus to asphalt modification.This paper presents an in-depth analysis and research on the composition,structure,and performance of epoxy asphalt materials for roads,so that this material can be widely used.
基金The National Natural Science Foundation of China(No.51178114)the Chinese Western Transportation Construction Technology Project of Transportation Ministry(No.2009318000086)
文摘To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt material performance tester AMPT .In order to evaluate the validity of the proposed fracture test four different loading rates including 1 2 3 and 4 mm/min are examined in the AMPT. The results indicate that the fracture behavior is similar to creep at a low loading rate and does not show significant marginal tail extension at a high loading rate.It clearly shows the phase of crack initiation crack propagation and fracture at a loading rate of 3 mm/min. Besides eight fracture parameters such as fracture energy tensile strength and tensile modulus are applied to evaluate the fracture characteristics of asphalt mixture.Development of the overlay tester for the fracture test of asphalt mixture can be considered as a new fracture test of asphalt mixture.
基金Funded by the National Natural Science Foundation of China(Nos.51408287 and 51668038)the Rolls Supported by Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R29)+2 种基金the Distinguished Young Scholars Fund of Gansu Province(1606RJDA318)the Natural Science Foundation of Gansu Province(1506RJZA064)the Excellent Program of Lanzhou Jiaotong University(201606)
文摘The objective of this paper was to develop a comprehensive evaluation method and index to evaluate the performance of sealants and fillers for cracks in asphalt concrete pavements using the method of principal component analysis. The performance experiments including cone penetration, softening point, flow, resilience and tension at low temperature respectively were conducted by reference of ASTM D5329 for eight sealants and fillers often used in China. There by a principal component model was developed and weight of every index was calculated. The experimental results show that there are significantly different performances for sealants and fillers often used in China. Principal component analysis is an objective method that evaluates and selects the performance of sealants and fillers for cracks in asphalt concrete pavements.
基金Funded by the National Natural Science Foundation of China(Nos.51408287,and 51668038)the Rolls Supported by Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R29)+2 种基金the Distinguished Young Scholars Fund of Gansu Province(1606RJDA318)the Natural Science Foundation of Gansu Province(1506RJZA064)the Excellent Program of Lanzhou Jiaotong University(201606)
文摘We investigated microstructure morphologies of three asphalts（SK, Karamay, and Esso） used in China using atomic force microscopy（AFM）. The topography and phase contrast images were obtained. Topographic profile and three dimensional images were described. Roughnesses of microstructure were calculated. And the chemical compositions of asphalt were tested to explain the microstructural mechanism of the asphalt. The results show that the topography and phase image in atomic force microscopy are appropriate to evaluate the microstructure of the asphalt binder. There are significant differences in microstructural morphologies including bee-like structure, topographic profile, 3D image, and roughness for three asphalts in this study. There are three different phases in microstructure of asphalt binder. The oil source and chemical composition of asphalt, especially asphaltenes content have a great influence on the microstructure.
文摘The aim of this paper is to present the results of a long-term research project consisting in the elaboration of a new rational airfield pavement design procedure applied to flexible pavements. The described methodology is based on the principles and the feedback obtained from the highway pavement design process which has been applied for more than 30 years in France as well as in many other countries. Adaptations to airfield pavements have been made, including features such as accurate traffic description, consideration of lateral wander of aircrafts for instance. The results of these developments have led to a new methodology which enables optimizing pavement designs by considering various input parameters such as the type of pavement section （runway, taxiway or apron）, the material properties and the temperature. The complete description of this method is available in the new pavement design manual and it is implemented in the dedicated software Aliz6-Airfield Pavement.
基金partially funded by the University Transportation Center for Materials in Sustainable Transportation Infrastructure at Michigan Technological University through the United States Department of Transportation(USDOT)
文摘This project integrates recent innovations of recycled materials used in designing and building sustainable pavements. An increasing environmental awareness and the demand for improving economic and construction efficiencies, through measures such as con- struction warrantees and goals to reduce air pollution under the Kyoto Protocol, have increased the efforts to implement sustainable materials in roadways. The objective of this research is to develop a systematic approach toward selecting optimum combinations of sustainable materials for the construction of asphalt pavements. The selected materials, warm mix asphalt （WMA）, recycled asphalt shingles {RAS）I and reclaimed asphalt pave- ment {RAP） were incorporated in this study. The results of this research are intended to serve as guidelines in the selection of the mixed sustainable materials for asphalt pave- ments. The approach developed from this project draws upon previous research efforts integrating graphical modeling with optimizing the amount of sustainable materials based on the performance. With regard to moisture susceptibility and rutting potential test re- suits, as well as the MIM analysis based on a 95% confidence interval, the rutting perfor- mance and moisture susceptibility of asphalt mixtures are not significantly different regardless of the percentages of RAS, RAP, or WMA. The optimum mixture choices could be made by the plant emission rankings with consideration of the optimal WMA types, per- centages of RAS/RAP, and WMA production temperatures. The WMA mixtures prepared with 75% RAP and Advera WMA have produced the lowest CO2 emissions among the investigated mixture types.
