Bio-asphalt has a great application prospect in the replacement of petroleum-based asphalt to pave and maintain asphalt pavement. However, the problems of flow-induced crystallization and phase separation caused by fl...Bio-asphalt has a great application prospect in the replacement of petroleum-based asphalt to pave and maintain asphalt pavement. However, the problems of flow-induced crystallization and phase separation caused by flowinduced crystallization had severely restricted its application. This paper describes the progress of research on preparation, property evaluation and phase separation mechanism of bio-asphalt. The advantages and disadvantages of preparation methods of bio-asphalt are states. The fundamental physical and rheological properties of bio-asphalt are investigated, especially for flow-induced crystallization. There exists obvious flow-induced crystallization because bio-asphalt is rich in waxes that crystallize easily. Owing to the existence of excess biochar,bio-asphalt appears phase separation. A brief review of the effect of bio-oil and biochar on asphalt volatile organic compounds(VOCs) is presented. Research find that bio-oil/biochar are not only replenish the light components of asphalt, but also improve the flow-induced crystallization and phase separation of bio-asphalt. There exists synergistic effect of biochar and bio-oil in asphalt modification. Moreover, biochar can improve the durability of bio-oil modified asphalt, but excessive addition of biochar to bio-oil modified asphalt can cause phase separation.Adding an appropriate amount of bio-oil and biochar to asphalt can improve its high-temperature resistance, lowtemperature crack resistance, and system compatibility.展开更多
Asphalt binder is inevitably aged by ultraviolet(UV)light during its service period.UV ageing can significantly decrease the technical properties of asphalt binder.The sensitivity of asphalt to UV ageing and thermal-o...Asphalt binder is inevitably aged by ultraviolet(UV)light during its service period.UV ageing can significantly decrease the technical properties of asphalt binder.The sensitivity of asphalt to UV ageing and thermal-oxidative ageing differs,such that the UV ageing performance cannot be determined based on the thermal-oxidative ageing performance.Previous researches mainly focused on the chemical composite and technical performance changes of asphalt binder during UV ageing,and the UV light parameters effect on the ageing rate of asphalt binder.However,the theory for characterizing and explaining the development of UV ageing depth does not get too much attentions,and the UV ageing mechanism of asphalt binder is not very clear.Therefore,it cannot guide to develop or select the good methods or anti-UV ageing additives for asphalt binders.This paper focuses on the latest researches of the mechanisms and anti-ageing methods of asphalt binders.With the increase of UV ageing time,the UV ageing of asphalt binder develops gradually from the surface to inner part.There are various methods,such as low-penetration grade asphalt,less air void ratio,UV stabilizers and UV light absorbers,that can improve the UV ageing resistance of asphalt binders.A new theory of sensitive wavelengths of asphalt UV ageing is proposed,which can enrich the basic theory of asphalt UV ageing.Depending on this theory,different wavelengths of UV light have different ageing effects on asphalt binder.The composite anti-UV ageing additives with barrier and specific absorption effects on UV light is proposed,and may have better improvement effect on the anti-UV ageing performance of asphalt binder.展开更多
This paper describes the design and experimental tests of a path planning and reference tracking algorithm for autonomous ground vehicles. The ground vehicles under consideration are equipped with forward looking sens...This paper describes the design and experimental tests of a path planning and reference tracking algorithm for autonomous ground vehicles. The ground vehicles under consideration are equipped with forward looking sensors that provide a preview capability over a certain horizon. A two-level control framework is proposed for real-time implementation of the model predictive control （MPC） algorithm, where the high-level performs on-line optimization to generate the best possible local reference respect to various constraints and the low-level commands the vehicle to follow realistic trajectories generated by the high-level controller. The proposed control scheme is implemented on an indoor testbed through networks with satisfactory performance.展开更多
This study was carried out to evaluate the resistance of overlaid pavement incorporating stress absorbing membrane interlayers to permanent deformation. In this study, the permanent deformation of the interlayer mixtu...This study was carried out to evaluate the resistance of overlaid pavement incorporating stress absorbing membrane interlayers to permanent deformation. In this study, the permanent deformation of the interlayer mixtures was determined using the RLAT （repeated load axial text） carried out in the Nottingham Asphalt Tester. Also, a test pavement was constructed in the laboratory to assess the resistance to permanent deformation of overlaid pavement incorporating SAMIs （stress absorbing membrane interlayers）. The test pavement was divided into two along the centre line. Each of the divisions has three sections--two having SAMIs and one without SAMIs. The pavement was instrumented and trafficked. Trafficking was stopped when the pavement was deemed to have failed. The results showed that the measured permanent deformation values of the control sections were less than the sections having SAMIs. The increased permanent deformation values indicate that the introduction of SAMIs causes more vertical/horizontal deformation of the pavement. It was also found that the permanent deformation values varied depending on the composition and thickness of the SAMIs.展开更多
基金supported by the National Natural Science Foundation of China (No. 52378456, No. W2421062, No. 52008235)the Special Foundation of Achievements Transformation Guide of Department of Science and Technology of Shanxi Province (No. 202204021301075, No.201804D131034)+1 种基金the Patent Transformation Project of Shanxi Province(No. 202306009)Shanxi Graduate Education Innovation Plan(2024SJ027)。
文摘Bio-asphalt has a great application prospect in the replacement of petroleum-based asphalt to pave and maintain asphalt pavement. However, the problems of flow-induced crystallization and phase separation caused by flowinduced crystallization had severely restricted its application. This paper describes the progress of research on preparation, property evaluation and phase separation mechanism of bio-asphalt. The advantages and disadvantages of preparation methods of bio-asphalt are states. The fundamental physical and rheological properties of bio-asphalt are investigated, especially for flow-induced crystallization. There exists obvious flow-induced crystallization because bio-asphalt is rich in waxes that crystallize easily. Owing to the existence of excess biochar,bio-asphalt appears phase separation. A brief review of the effect of bio-oil and biochar on asphalt volatile organic compounds(VOCs) is presented. Research find that bio-oil/biochar are not only replenish the light components of asphalt, but also improve the flow-induced crystallization and phase separation of bio-asphalt. There exists synergistic effect of biochar and bio-oil in asphalt modification. Moreover, biochar can improve the durability of bio-oil modified asphalt, but excessive addition of biochar to bio-oil modified asphalt can cause phase separation.Adding an appropriate amount of bio-oil and biochar to asphalt can improve its high-temperature resistance, lowtemperature crack resistance, and system compatibility.
基金The authors acknowledge the financial supported by National Natural Science Foundation of China(No.52108415 and No.51808517)the National Key R&D Program of China(No.2018YFB1600200)+5 种基金the Key Technical Innovation Projects of Hubei Province(No.2019AEE023)the Key R&D Program of Hubei Province(No.2020BCB064)the State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)(No.SYSJJ2022-21),the Transportation Technology Project of Department of Transport of Hubei Province(No.2022-11-1-10)the European Union's Horizon 2020 Research and Innovation Programme Under the Marie Skłodowska-Curie Grant Agreement(No.101030767)the Scientific Research Fund Project of Wuhan Institute of Technology(No.K2021032)the Open Fund of National&Local Joint Engineering Laboratory of Traffic Civil Engineering Materials,Chongqing Jiaotong University(No.LHSYS-2020-004).
文摘Asphalt binder is inevitably aged by ultraviolet(UV)light during its service period.UV ageing can significantly decrease the technical properties of asphalt binder.The sensitivity of asphalt to UV ageing and thermal-oxidative ageing differs,such that the UV ageing performance cannot be determined based on the thermal-oxidative ageing performance.Previous researches mainly focused on the chemical composite and technical performance changes of asphalt binder during UV ageing,and the UV light parameters effect on the ageing rate of asphalt binder.However,the theory for characterizing and explaining the development of UV ageing depth does not get too much attentions,and the UV ageing mechanism of asphalt binder is not very clear.Therefore,it cannot guide to develop or select the good methods or anti-UV ageing additives for asphalt binders.This paper focuses on the latest researches of the mechanisms and anti-ageing methods of asphalt binders.With the increase of UV ageing time,the UV ageing of asphalt binder develops gradually from the surface to inner part.There are various methods,such as low-penetration grade asphalt,less air void ratio,UV stabilizers and UV light absorbers,that can improve the UV ageing resistance of asphalt binders.A new theory of sensitive wavelengths of asphalt UV ageing is proposed,which can enrich the basic theory of asphalt UV ageing.Depending on this theory,different wavelengths of UV light have different ageing effects on asphalt binder.The composite anti-UV ageing additives with barrier and specific absorption effects on UV light is proposed,and may have better improvement effect on the anti-UV ageing performance of asphalt binder.
文摘This paper describes the design and experimental tests of a path planning and reference tracking algorithm for autonomous ground vehicles. The ground vehicles under consideration are equipped with forward looking sensors that provide a preview capability over a certain horizon. A two-level control framework is proposed for real-time implementation of the model predictive control （MPC） algorithm, where the high-level performs on-line optimization to generate the best possible local reference respect to various constraints and the low-level commands the vehicle to follow realistic trajectories generated by the high-level controller. The proposed control scheme is implemented on an indoor testbed through networks with satisfactory performance.
文摘This study was carried out to evaluate the resistance of overlaid pavement incorporating stress absorbing membrane interlayers to permanent deformation. In this study, the permanent deformation of the interlayer mixtures was determined using the RLAT （repeated load axial text） carried out in the Nottingham Asphalt Tester. Also, a test pavement was constructed in the laboratory to assess the resistance to permanent deformation of overlaid pavement incorporating SAMIs （stress absorbing membrane interlayers）. The test pavement was divided into two along the centre line. Each of the divisions has three sections--two having SAMIs and one without SAMIs. The pavement was instrumented and trafficked. Trafficking was stopped when the pavement was deemed to have failed. The results showed that the measured permanent deformation values of the control sections were less than the sections having SAMIs. The increased permanent deformation values indicate that the introduction of SAMIs causes more vertical/horizontal deformation of the pavement. It was also found that the permanent deformation values varied depending on the composition and thickness of the SAMIs.
