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
Nowadays, asphalt road has dominated highways around the world. Among various defects of asphalt road, crackshave been paid more attention, since cracks often cause major engineering and personnel safety incidents. Cu...Nowadays, asphalt road has dominated highways around the world. Among various defects of asphalt road, crackshave been paid more attention, since cracks often cause major engineering and personnel safety incidents. Currentmanual crack inspection methods are time-consuming and labor-intensive, and most segmentation methods cannot detect cracks at the pixel level. This paper proposes an intelligent segmentation and measurement model basedon the modified Mask R-CNN algorithm to automatically and accurately detect asphalt road cracks. The modelproposed in this paper mainly includes a convolutional neural network (CNN), an optimized region proposalnetwork (RPN), a region of interest (RoI) Align layer, a candidate area classification network and a Mask branch offully convolutional network (FCN). The ratio and size of anchors in the RPN are adjusted to improve the accuracyand efficiency of segmentation. Soft non-maximum suppression (Soft-NMS) algorithm is developed to improvethe segmentation accuracy. A dataset including 8,689 images (512× 512 pixels) of asphalt cracks is established andthe road crack is manually marked. Transfer learning is used to initialize the model parameters in the trainingprocess. To optimize the model training parameters, multiple comparison experiments are performed, and the testresults show that the mean average precision (mAP) value and F1-score of the optimal trained model are 0.952 and0.949. Subsequently, the robustness verification test and comparative test of the trained model are conducted andthe topological features of the crack are extracted. Then, the damage area, length and average width of the crackare measured automatically and accurately at pixel level. More importantly, this paper develops an automatic crackdetection platform for asphalt roads to automatically extract the number, area, length and average width of cracks,which can significantly improve the crack detection efficiency for the road maintenance industry.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
In order to analyze the effect of different loading frequencies on the fatigue performance for asphalt mixture,the changing law of asphalt mixture strengths with loading speed was revealed by strength tests under diff...In order to analyze the effect of different loading frequencies on the fatigue performance for asphalt mixture,the changing law of asphalt mixture strengths with loading speed was revealed by strength tests under different loading speeds.Fatigue equations of asphalt mixtures based on the nominal stress ratio and real stress ratio were established using fatigue tests under different loading frequencies.It was revealed that the strength of the asphalt mixture is affected by the loading speed greatly.It was also discovered that the fatigue equation based on the nominal stress ratio will change with the change of the fatigue loading speed.There is no uniqueness.But the fatigue equation based on the real stress ratio doesn't change with the loading frequency.It has the uniqueness.The results indicate the fatigue equation based on the real stress ratio can realize the normalization of the asphalt mixture fatigue equation under different loading frequencies.It can greatly benefit the analysis of the fatigue characteristics under different vehicle speeds for asphalt pavement.展开更多
The process of performance degradation of road asphalt(RA)is regarded as aging.At present,better understanding of the thermal-oxidative aging of asphalt is achieved and the corresponding method to evaluate this proces...The process of performance degradation of road asphalt(RA)is regarded as aging.At present,better understanding of the thermal-oxidative aging of asphalt is achieved and the corresponding method to evaluate this process is developed;meanwhile,photo-oxidative aging(aging in an atmospheric environment,which is referred to as“outdoor aging”in this paper)of asphalt remains at the initial stages of scientific exploration.The outdoor natural ultraviolet(UV)aging of RA and SBS modified asphalt(SBSMA)are investigated in this study.The experimental results show that the basic performances of RA and SBSMA present similar change tendencies.The softening point increased,while the penetration and ductility decreased as the outdoor aging time passed by,and the 5℃ ductility(ductility measured at 5℃)of SBSMA decreased very quickly.The group components of RA and SBSMA also change during UV aging.The content of asphaltene rose and that of aromatics and saturates decreased,while the content of resins changed insignificantly.Moreover,the Fourier transform infrared(FTIR)graphs show that the content of sulfoxide and carbonyl groups in RA and SBSMA increased significantly during the outdoor aging process.展开更多
Longitudinal cracking is one of the most important distresses of asphalt pavement in permafrost regions. The sensitivity analysis of design parameters for asphalt pavement can be used to study the influence of every p...Longitudinal cracking is one of the most important distresses of asphalt pavement in permafrost regions. The sensitivity analysis of design parameters for asphalt pavement can be used to study the influence of every parameter on longitudinal cracking, which can help optimizing the design of the pavement structure. In this study, 20 test sections of Qinghai-Tibet Highway were selected to conduct the sensitivity analysis of longi- tudinal cracking on material parameter based on Mechanistic-Empirical Pavement Design Guide (MEPDG) and single factorial sensitivity analysis method. Some computer aided engineering (CAE) simulation techniques, such as the Latin hypercube sampling (LHS) technique and the multiple regression analysis are used as auxiliary means. Finally, the sensitivity spectrum of material parameter on longitudinal cracking was established. The result shows the multiple regression analysis can be used to determine the remarkable influence factor more efficiently and to process the qualitative analysis when applying the MEPDG software in sensitivity analysis of longitudinal cracking in permafrost regions. The effect weights of the three parameters on longitudinal cracking in descending order are air void, effective binder content and PG grade. The influence of air void on top layer is bigger than that on middle layer and bottom layer. The influence of effective asphalt content on top layer is bigger than that on middle layer and bottom layer, and the influence of bottom layer is slightly bigger than middle layer. The accumulated value of longitudinal cracking on middle layer and bottom layer in the design life would begin to increase when the design temperature of PG grade increased.展开更多
Warm mix asphalt (WMA} is a new technology which asphalt mix is produced and placed at normal temperature. It has advantages including low cost, environmentally friendly, haul-convenience, and so on. WMA has been wid...Warm mix asphalt (WMA} is a new technology which asphalt mix is produced and placed at normal temperature. It has advantages including low cost, environmentally friendly, haul-convenience, and so on. WMA has been widely tested and applied in the USA in the last decade, but it has just started in China. Recently, a new WMA using a new plastic- macromolecule-normal temperature additive, which was called "SMC" by the production company, was introduced as asphalt modifier. Based on discussing the strength forming process of this new WMA with SMC, a series of laboratory tests, including Marshall stability test (MST), boiling test (BT), modified immersion Marshall test (MIMT), freeze-thaw split- ring test (FTST), rutting test (RT), low-temperature bending test (LTBT), and abrasion loss test (ALT), were conducted in this study to assess the performance of this WMA and the capability of applying it on low volume roads in China. SMC modified asphalt mixed under normal temperature is used in testing samples. It was found that this WMA product exhibited merits on its strength, which was about 6.7 kN bigger than the requirement of 5.0 kN in the JTG F40-2004, on high-temperature stability, which is about 1100 times/ram greater than the requirement of 600-1000 times/mm in the )TG F40-2004, and on its storage stability. Based on these indicators, it is recommended that this product could be used for low volume low class roads construction. However, due to the relatively lower water resistance and low-temperature cracking resistance, this product is suggested to be applied first in the areas with warm weather and little rainfall. In order to improve the perfor- mance of this WMA with SMC, further research on this SMC asphalt modifier should be continued.展开更多
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This research was funded by the National Key Research and Development Program of China(No.2017YFC1501204)the National Natural Science Foundation of China(No.51678536)+4 种基金the Guangdong Innovative and Entrepreneurial Research Team Program(2016ZT06N340)the Program for Science and Technology Innovation Talents in Universities of Henan Province(Grant No.19HASTIT043)the Outstanding Young Talent Research Fund of Zhengzhou University(1621323001)the Program for Innovative Research Team(in Science and Technology)in University of Henan Province(18IRTSTHN007)the Research on NonDestructive Testing(NDT)and Rapid Evaluation Technology for Grouting Quality of Prestressed Ducts(Contract No.HG-GCKY-01-002).The authors would like to thank for these financial supports.
文摘Nowadays, asphalt road has dominated highways around the world. Among various defects of asphalt road, crackshave been paid more attention, since cracks often cause major engineering and personnel safety incidents. Currentmanual crack inspection methods are time-consuming and labor-intensive, and most segmentation methods cannot detect cracks at the pixel level. This paper proposes an intelligent segmentation and measurement model basedon the modified Mask R-CNN algorithm to automatically and accurately detect asphalt road cracks. The modelproposed in this paper mainly includes a convolutional neural network (CNN), an optimized region proposalnetwork (RPN), a region of interest (RoI) Align layer, a candidate area classification network and a Mask branch offully convolutional network (FCN). The ratio and size of anchors in the RPN are adjusted to improve the accuracyand efficiency of segmentation. Soft non-maximum suppression (Soft-NMS) algorithm is developed to improvethe segmentation accuracy. A dataset including 8,689 images (512× 512 pixels) of asphalt cracks is established andthe road crack is manually marked. Transfer learning is used to initialize the model parameters in the trainingprocess. To optimize the model training parameters, multiple comparison experiments are performed, and the testresults show that the mean average precision (mAP) value and F1-score of the optimal trained model are 0.952 and0.949. Subsequently, the robustness verification test and comparative test of the trained model are conducted andthe topological features of the crack are extracted. Then, the damage area, length and average width of the crackare measured automatically and accurately at pixel level. More importantly, this paper develops an automatic crackdetection platform for asphalt roads to automatically extract the number, area, length and average width of cracks,which can significantly improve the crack detection efficiency for the road maintenance industry.
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Projects(51208066,51038002)supported by the National Natural Science Foundation of ChinaProject(20114316120001)supported by Specialized Research Fund for the Doctoral Program of Higher Education,China+5 种基金Project(2012-319-825-150)supported by Application and Basic Research Projects of Ministry of Transport ChinaProject(2013K28)supported by Transportation Science and Technology Plan Projects of Henan Province,ChinaProject(201102)supported by Transportation Science and Technology Plan Projects of Hunan Province,ChinaProject(YB2012B031)supported by Funding Projects of Hunan Provincial Outstanding Doctorate Dissertation,ChinaProject(2014gxjgclkf-002)supported by Open Fund of Key Laboratory of Road Structure and Material of Guangxi Province ChinaProject(kfj120101)supported by Open Fund of the Key Laboratory of Highway Engineering(Changsha University of Science and Technology),China
文摘In order to analyze the effect of different loading frequencies on the fatigue performance for asphalt mixture,the changing law of asphalt mixture strengths with loading speed was revealed by strength tests under different loading speeds.Fatigue equations of asphalt mixtures based on the nominal stress ratio and real stress ratio were established using fatigue tests under different loading frequencies.It was revealed that the strength of the asphalt mixture is affected by the loading speed greatly.It was also discovered that the fatigue equation based on the nominal stress ratio will change with the change of the fatigue loading speed.There is no uniqueness.But the fatigue equation based on the real stress ratio doesn't change with the loading frequency.It has the uniqueness.The results indicate the fatigue equation based on the real stress ratio can realize the normalization of the asphalt mixture fatigue equation under different loading frequencies.It can greatly benefit the analysis of the fatigue characteristics under different vehicle speeds for asphalt pavement.
基金supported by the State Key Laboratory of Heavy Oil Processing,China University of Petroleumthe authors would like to acknowledge their financial support.
文摘The process of performance degradation of road asphalt(RA)is regarded as aging.At present,better understanding of the thermal-oxidative aging of asphalt is achieved and the corresponding method to evaluate this process is developed;meanwhile,photo-oxidative aging(aging in an atmospheric environment,which is referred to as“outdoor aging”in this paper)of asphalt remains at the initial stages of scientific exploration.The outdoor natural ultraviolet(UV)aging of RA and SBS modified asphalt(SBSMA)are investigated in this study.The experimental results show that the basic performances of RA and SBSMA present similar change tendencies.The softening point increased,while the penetration and ductility decreased as the outdoor aging time passed by,and the 5℃ ductility(ductility measured at 5℃)of SBSMA decreased very quickly.The group components of RA and SBSMA also change during UV aging.The content of asphaltene rose and that of aromatics and saturates decreased,while the content of resins changed insignificantly.Moreover,the Fourier transform infrared(FTIR)graphs show that the content of sulfoxide and carbonyl groups in RA and SBSMA increased significantly during the outdoor aging process.
基金supported by research project of Ministry of Science and Technology of China (2014BAG05B04)research project of Ministry of Transport of China (2012319495030)the Special Fund for Basic Scientific Research of Central Colleges, Chang'an University (CHD2013G3212003)
文摘Longitudinal cracking is one of the most important distresses of asphalt pavement in permafrost regions. The sensitivity analysis of design parameters for asphalt pavement can be used to study the influence of every parameter on longitudinal cracking, which can help optimizing the design of the pavement structure. In this study, 20 test sections of Qinghai-Tibet Highway were selected to conduct the sensitivity analysis of longi- tudinal cracking on material parameter based on Mechanistic-Empirical Pavement Design Guide (MEPDG) and single factorial sensitivity analysis method. Some computer aided engineering (CAE) simulation techniques, such as the Latin hypercube sampling (LHS) technique and the multiple regression analysis are used as auxiliary means. Finally, the sensitivity spectrum of material parameter on longitudinal cracking was established. The result shows the multiple regression analysis can be used to determine the remarkable influence factor more efficiently and to process the qualitative analysis when applying the MEPDG software in sensitivity analysis of longitudinal cracking in permafrost regions. The effect weights of the three parameters on longitudinal cracking in descending order are air void, effective binder content and PG grade. The influence of air void on top layer is bigger than that on middle layer and bottom layer. The influence of effective asphalt content on top layer is bigger than that on middle layer and bottom layer, and the influence of bottom layer is slightly bigger than middle layer. The accumulated value of longitudinal cracking on middle layer and bottom layer in the design life would begin to increase when the design temperature of PG grade increased.
基金the financial support of National Natural Science Foundation of China(51378438)National 973 Program(2013CB036204)specific research funding from Ministry of Education(SWJTU12ZT05)
文摘Warm mix asphalt (WMA} is a new technology which asphalt mix is produced and placed at normal temperature. It has advantages including low cost, environmentally friendly, haul-convenience, and so on. WMA has been widely tested and applied in the USA in the last decade, but it has just started in China. Recently, a new WMA using a new plastic- macromolecule-normal temperature additive, which was called "SMC" by the production company, was introduced as asphalt modifier. Based on discussing the strength forming process of this new WMA with SMC, a series of laboratory tests, including Marshall stability test (MST), boiling test (BT), modified immersion Marshall test (MIMT), freeze-thaw split- ring test (FTST), rutting test (RT), low-temperature bending test (LTBT), and abrasion loss test (ALT), were conducted in this study to assess the performance of this WMA and the capability of applying it on low volume roads in China. SMC modified asphalt mixed under normal temperature is used in testing samples. It was found that this WMA product exhibited merits on its strength, which was about 6.7 kN bigger than the requirement of 5.0 kN in the JTG F40-2004, on high-temperature stability, which is about 1100 times/ram greater than the requirement of 600-1000 times/mm in the )TG F40-2004, and on its storage stability. Based on these indicators, it is recommended that this product could be used for low volume low class roads construction. However, due to the relatively lower water resistance and low-temperature cracking resistance, this product is suggested to be applied first in the areas with warm weather and little rainfall. In order to improve the perfor- mance of this WMA with SMC, further research on this SMC asphalt modifier should be continued.