In order to simplify the boundary conditions of pavement temperature field,the "Environment-Surface" system which considered the natural environment and pavement surface was established.Based on this system,...In order to simplify the boundary conditions of pavement temperature field,the "Environment-Surface" system which considered the natural environment and pavement surface was established.Based on this system,the partial differential equations of the one-dimensional heat conduction in the pavement were established on the basis of the heat transfer theory.Furthermore,the function forms of the initial and boundary conditions of the equations were created through the field experiments.The general solution of the pavement one-dimensional heat conduction partial differential equations was acquired by using Green's function,and the explicit expression of pavement temperature field under specific constraint conditions was derived.For the purpose of analysis,the pavement temperatures in different seasons were calculated using the explicit expression of pavement temperature field,and the calculation accuracy was analyzed through the comparison between measured and calculated values.Then,the relationship between fitting accuracy and calculation accuracy of pavement temperatures was analyzed.The analysis results show that: the usage of "Environment-Surface" system simplifies the calculation of pavement temperature field; the relative error between calculated and measured values is generally less than 7% and is seldom influenced by seasons; there is a positive correlation between the calculation accuracy and the fitting accuracy of pavement surface temperature; high fitting accuracy would result in less error of pavement temperature prediction.展开更多
The elevated temperatures adversely affect the durability and lifespan of pavement.Understanding the factors that influence asphalt pavement temperature offers valuable insights for creating climate-friendly cities wi...The elevated temperatures adversely affect the durability and lifespan of pavement.Understanding the factors that influence asphalt pavement temperature offers valuable insights for creating climate-friendly cities with cooler pavement surfaces.In this study,three aggregates of varying types and colors,two types of bitumen(one without pigment and one with the addition of red pigment,Fe2O3),and two levels of mean texture depth(MTD),high and low,were utilized to create asphalt samples using Marshall's method.A total of 38 thermocouple sensors were employed to simultaneously record temperatures in three areas within the samples,as well as the temperatures in shaded and sunlit conditions over a period of 17 days.Furthermore,a comprehensive evaluation was conducted to assess the impact of each factor on the solar reflectance index(SRI).Twelve general linear models(GLMs)were developed using a full factorial design of experiment,and five models with an R2 greater than 95%were evaluated and analyzed.The analysis,based on the coefficients derived from the GLMs,indicates that the mean MTD is the most significant parameter affecting surface temperature.Pigment color emerged as the second most influential factor affecting both surface and bottom temperatures.Additionally,the findings revealed that MTD has the greatest impact on the SRI,followed by pigment color and aggregate color.It was also determined that the interaction between density,pigment color,and aggregate color plays a crucial role in determining the temperatures of both the surface and bottom of the specimens.展开更多
In this paper, the research on warm mix asphalt construction technology of asphalt surface course in low temperature season in cold areas is carried out. The research project is guided by surface theory, mortar theory...In this paper, the research on warm mix asphalt construction technology of asphalt surface course in low temperature season in cold areas is carried out. The research project is guided by surface theory, mortar theory, strength theory and asphalt concrete regulations, based on solid engineering practice, aiming at breaking through the bottleneck of Asphalt Mixture Construction under low temperature environment, through repeated tests and optimization. Carry out a series of studies including the selection of warm mix agent, the formula, road performance and construction technology of warm mix asphalt mixture, and start from four aspects: the selection of warm mix agent, the proportion and technology of warm mix asphalt mixture, the road performance of warm mix asphalt mixture and the construction technology of warm mix asphalt mixture expressway. It has formed a complete set of technical scheme and control standard system for selecting and determining the optimal type and dosage of warm mix agent, reasonable raw material ratio, mixing process and parameters, road performance and applicability of warm mix asphalt mixture, and construction of warm mix asphalt process in low temperature season of asphalt pavement engineering.展开更多
The application of de-icing salts to improve winter road safety,although necessary in cold climates,may adversely affect groundwater resources and degrade aquatic life in urban streams,if over-prescribed,and cause an ...The application of de-icing salts to improve winter road safety,although necessary in cold climates,may adversely affect groundwater resources and degrade aquatic life in urban streams,if over-prescribed,and cause an increase in crash rates,if under-prescribed.The main objective of this research is to develop algorithms for precision salt application rate(SAR)using advanced machine learning methods to achieve the desired road safety with less adverse environmental effects.This study highlights the importance of accurate realtime monitoring of pavement surface temperature and meteorological variables(i.e.,storm duration,hourly precipitation rate,and air temperature)as key factors in prescribing salt application rates during winter storm events.A new SAR model was trained/tested using a decade of historic salt application rates from a range of winter storm events on three different road classes.The application of this model can help road authorities to achieve greater road safety and reduce adverse environmental impacts,especially in the identified and mapped salt vulnerable areas.展开更多
基金Projects(2012zzts019,2012QNZT048)supported by the Fundamental Research Funds for the Central Universities of Central South University,ChinaProject(201306370121)supported by the State Scholarship Fund of China+3 种基金Project(JT20090898002)supported by Traffic Technology Fund of Hainan Province,ChinaProject(2012M521563)supported by the China Postdoctoral Science FoundationProject(51248006)supported by The National Natural Science Foundation of ChinaProject(511114)supported by the Natural Science Foundation of Hainan Province,China
文摘In order to simplify the boundary conditions of pavement temperature field,the "Environment-Surface" system which considered the natural environment and pavement surface was established.Based on this system,the partial differential equations of the one-dimensional heat conduction in the pavement were established on the basis of the heat transfer theory.Furthermore,the function forms of the initial and boundary conditions of the equations were created through the field experiments.The general solution of the pavement one-dimensional heat conduction partial differential equations was acquired by using Green's function,and the explicit expression of pavement temperature field under specific constraint conditions was derived.For the purpose of analysis,the pavement temperatures in different seasons were calculated using the explicit expression of pavement temperature field,and the calculation accuracy was analyzed through the comparison between measured and calculated values.Then,the relationship between fitting accuracy and calculation accuracy of pavement temperatures was analyzed.The analysis results show that: the usage of "Environment-Surface" system simplifies the calculation of pavement temperature field; the relative error between calculated and measured values is generally less than 7% and is seldom influenced by seasons; there is a positive correlation between the calculation accuracy and the fitting accuracy of pavement surface temperature; high fitting accuracy would result in less error of pavement temperature prediction.
文摘The elevated temperatures adversely affect the durability and lifespan of pavement.Understanding the factors that influence asphalt pavement temperature offers valuable insights for creating climate-friendly cities with cooler pavement surfaces.In this study,three aggregates of varying types and colors,two types of bitumen(one without pigment and one with the addition of red pigment,Fe2O3),and two levels of mean texture depth(MTD),high and low,were utilized to create asphalt samples using Marshall's method.A total of 38 thermocouple sensors were employed to simultaneously record temperatures in three areas within the samples,as well as the temperatures in shaded and sunlit conditions over a period of 17 days.Furthermore,a comprehensive evaluation was conducted to assess the impact of each factor on the solar reflectance index(SRI).Twelve general linear models(GLMs)were developed using a full factorial design of experiment,and five models with an R2 greater than 95%were evaluated and analyzed.The analysis,based on the coefficients derived from the GLMs,indicates that the mean MTD is the most significant parameter affecting surface temperature.Pigment color emerged as the second most influential factor affecting both surface and bottom temperatures.Additionally,the findings revealed that MTD has the greatest impact on the SRI,followed by pigment color and aggregate color.It was also determined that the interaction between density,pigment color,and aggregate color plays a crucial role in determining the temperatures of both the surface and bottom of the specimens.
文摘In this paper, the research on warm mix asphalt construction technology of asphalt surface course in low temperature season in cold areas is carried out. The research project is guided by surface theory, mortar theory, strength theory and asphalt concrete regulations, based on solid engineering practice, aiming at breaking through the bottleneck of Asphalt Mixture Construction under low temperature environment, through repeated tests and optimization. Carry out a series of studies including the selection of warm mix agent, the formula, road performance and construction technology of warm mix asphalt mixture, and start from four aspects: the selection of warm mix agent, the proportion and technology of warm mix asphalt mixture, the road performance of warm mix asphalt mixture and the construction technology of warm mix asphalt mixture expressway. It has formed a complete set of technical scheme and control standard system for selecting and determining the optimal type and dosage of warm mix agent, reasonable raw material ratio, mixing process and parameters, road performance and applicability of warm mix asphalt mixture, and construction of warm mix asphalt process in low temperature season of asphalt pavement engineering.
基金funded by the Ministry of Transportation of Ontario,and the Natural Sciences and Engineering Research Council of Canada,alliance grant#401643。
文摘The application of de-icing salts to improve winter road safety,although necessary in cold climates,may adversely affect groundwater resources and degrade aquatic life in urban streams,if over-prescribed,and cause an increase in crash rates,if under-prescribed.The main objective of this research is to develop algorithms for precision salt application rate(SAR)using advanced machine learning methods to achieve the desired road safety with less adverse environmental effects.This study highlights the importance of accurate realtime monitoring of pavement surface temperature and meteorological variables(i.e.,storm duration,hourly precipitation rate,and air temperature)as key factors in prescribing salt application rates during winter storm events.A new SAR model was trained/tested using a decade of historic salt application rates from a range of winter storm events on three different road classes.The application of this model can help road authorities to achieve greater road safety and reduce adverse environmental impacts,especially in the identified and mapped salt vulnerable areas.
