The aim of this study is to investigate the asphalt mixture anisotropy of both the modulus and Poisson＇s ratio due to air voids using a discrete element modeling simulation method. Three three-dimensional cubic digit...The aim of this study is to investigate the asphalt mixture anisotropy of both the modulus and Poisson＇s ratio due to air voids using a discrete element modeling simulation method. Three three-dimensional cubic digital samples of asphalt mixture with different shapes of single air void were built using discrete element software PFC^（3D）. The aggregate gradation, air voids and mastic included in the digital samples were modeled using different contact models, with due consideration of the volumetric fractions of the different phases. Laboratory uniaxial complex modulus test and indirect tensile strength test were conducted to obtain material input parameters for numerical modeling. Simulation of the uniaxial cyclic compressive tests was performed on the three cubic samples loaded in three different directions. Dynamic modulus in three directions and Poisson＇s ratio in six directions were calculated from the compression stress-strain responses. Results show that both the modulus and Poisson＇s ratio are dependent on the preferential orientation of air voids. The anisotropy of the modulus and Poisson＇s ratio increases as the pressure loading on the asphalt mixture increases. Compared to the modulus, Poisson＇s ratio due to air voids has been shown to be more anisotropic. The maximum of Poisson＇s ratio and modulus is shown to be up to 80% and 11% higher than the minimum, respectively.展开更多
The fatigue damage is one of the most common distresses observed on the asphalt concrete pavement.To thoroughly understand the fatigue of asphalt concrete,the behaviors of the major components of asphalt concrete unde...The fatigue damage is one of the most common distresses observed on the asphalt concrete pavement.To thoroughly understand the fatigue of asphalt concrete,the behaviors of the major components of asphalt concrete under cyclic loading are investigated respectively in this study.A new experiment method is developed to evaluate the performances of asphalt binder,mastic and fine aggregates mixture under cyclic tensile loading.The fatigue test results of asphalt binder show that the fatigue performance of asphalt binder is closely related with loading magnitude,temperature and loading rate.Mastic specimens with different filler content are tested and the results indicate that mastic specimens with 30%filler content show better fatigue resistance and higher permanent strain.The micro-structure analysis of mastic and mixture indicates that the fatigue resistance is closely related with the air void content of specimen.3D digital specimens are developed to model the fatigue of the asphalt binder,mastic and mixture specimens based on the finite element method(FEM).Fatigue damage of asphalt concrete is simplified by a damage model.With proper selection of damage parameters,the simulation results agree well with laboratory test results and can be used as a basis for future fatigue research.展开更多
基金Funded by the National Natural Science Foundation of China(No.51208178)the Fundamental Research Funds for the Central Universities(No.2015B17014)
文摘The aim of this study is to investigate the asphalt mixture anisotropy of both the modulus and Poisson＇s ratio due to air voids using a discrete element modeling simulation method. Three three-dimensional cubic digital samples of asphalt mixture with different shapes of single air void were built using discrete element software PFC^（3D）. The aggregate gradation, air voids and mastic included in the digital samples were modeled using different contact models, with due consideration of the volumetric fractions of the different phases. Laboratory uniaxial complex modulus test and indirect tensile strength test were conducted to obtain material input parameters for numerical modeling. Simulation of the uniaxial cyclic compressive tests was performed on the three cubic samples loaded in three different directions. Dynamic modulus in three directions and Poisson＇s ratio in six directions were calculated from the compression stress-strain responses. Results show that both the modulus and Poisson＇s ratio are dependent on the preferential orientation of air voids. The anisotropy of the modulus and Poisson＇s ratio increases as the pressure loading on the asphalt mixture increases. Compared to the modulus, Poisson＇s ratio due to air voids has been shown to be more anisotropic. The maximum of Poisson＇s ratio and modulus is shown to be up to 80% and 11% higher than the minimum, respectively.
基金This paper was financially supported by Guangxi Governor Grant under approval number of 2010-169the National Natural Science Foundation of China under Grant number of 41162011+2 种基金Guangxi Grand Natural Science Foundation under contract number of 2011GXNSFD018001Guangxi Grand Natural Science Foundation under the number of 2012GXNSFCB053005the grant of the Guangxi Key Laboratory of Spatial Information and Geomatics under contract number,GuiKeNeng110-31-08-01.
文摘The fatigue damage is one of the most common distresses observed on the asphalt concrete pavement.To thoroughly understand the fatigue of asphalt concrete,the behaviors of the major components of asphalt concrete under cyclic loading are investigated respectively in this study.A new experiment method is developed to evaluate the performances of asphalt binder,mastic and fine aggregates mixture under cyclic tensile loading.The fatigue test results of asphalt binder show that the fatigue performance of asphalt binder is closely related with loading magnitude,temperature and loading rate.Mastic specimens with different filler content are tested and the results indicate that mastic specimens with 30%filler content show better fatigue resistance and higher permanent strain.The micro-structure analysis of mastic and mixture indicates that the fatigue resistance is closely related with the air void content of specimen.3D digital specimens are developed to model the fatigue of the asphalt binder,mastic and mixture specimens based on the finite element method(FEM).Fatigue damage of asphalt concrete is simplified by a damage model.With proper selection of damage parameters,the simulation results agree well with laboratory test results and can be used as a basis for future fatigue research.
