The degradation behavior of aggregate skeleton in stone matrix asphalt mixture was investigated based on theoretical analysis, laboratory test and field materials evaluation. A stress-transfer model was established to...The degradation behavior of aggregate skeleton in stone matrix asphalt mixture was investigated based on theoretical analysis, laboratory test and field materials evaluation. A stress-transfer model was established to provide the fundamental understanding of the stress distribution and degradation mechanism of stone matrix asphalt (SMA) aggregate skeleton. Based on the theoretical analysis, crushing test and superpave gyratory compactor (SGC) test were used to evaluate the degradation behavior of aggregate skeleton of SMA. To verify the laboratory test results, gradation analysis was also conducted for the field materials extracted from SMA pavements after long-time service. The results indicate that the degradation of SMA aggregate skeleton is not random but has fixed internal trend and mechanism. Special rule is found for the graded fine aggregates generated from coarse aggregate breakdown and the variation of 4.75 mm aggregate is found to play a key role in the graded aggregates to form well-balanced skeleton to bear external loading. The variation of 4.75 mm aggregate together with the breakdown ratio of aggregate gradation can be used to characterize the degradation behavior of aggregate skeleton. The crushing test and SGC test are proved to be promising in estimating the degradation behavior of SMA skeleton.展开更多
Crack is found to be a major distress that affects the performance of the epoxy asphalt pavement.An extended finite element method was proposed for investigating the fracture properties of the epoxy asphalt mixture.Fi...Crack is found to be a major distress that affects the performance of the epoxy asphalt pavement.An extended finite element method was proposed for investigating the fracture properties of the epoxy asphalt mixture.Firstly,the single-edge notched beam test was used to analyze the temperature effect and calculate the material parameters.Then,the mechanical responses were studied using numerical analysis.It is concluded that 5℃ can be selected as the critical temperature that affects the fracture properties,and numerical simulations indicate that crack propagation is found to significantly affect the stress state of the epoxy asphalt mixture.The maximum principal stress at the crack surface exhibits different trends at various temperatures.Numerical solution of stress intensity factor can well meet the theoretical solution,especially when the temperature is lower than 5℃.展开更多
A research project was initiated by INDOT to estimate the structural contribution and feasibility of FDR bases for pavement structure under a low-medium volume traffic loading. FWD tests were conducted and the layer m...A research project was initiated by INDOT to estimate the structural contribution and feasibility of FDR bases for pavement structure under a low-medium volume traffic loading. FWD tests were conducted and the layer moduli were back calculated on different construction phases： the surface of existing HMA pavement, the FDR base, the new HMA final surface, and the nine months＇ traffic opening, respectively, for a total of four times. The results indicate the promise of this recycled base material in pavement construction compared to traditional granular base. In addition, this paper discusses how the lab test results relate to the expected performance in a pavement structure by the MEPDG software and its parameter effects. Research indicated the MEPDG provided comparable thickness to the 1993 AASHTO Guide if the failure criteria are set up reasonably. Therefore, the MEPDG could be used as a design tool to estimate layer thickness for FDR pavement with a low-medium traffic volume.展开更多
基金Project(51008075) supported by the National Natural Science Foundation of ChinaProject(2006AA11Z110) supported by the National High Technology Research and Development Program of China
文摘The degradation behavior of aggregate skeleton in stone matrix asphalt mixture was investigated based on theoretical analysis, laboratory test and field materials evaluation. A stress-transfer model was established to provide the fundamental understanding of the stress distribution and degradation mechanism of stone matrix asphalt (SMA) aggregate skeleton. Based on the theoretical analysis, crushing test and superpave gyratory compactor (SGC) test were used to evaluate the degradation behavior of aggregate skeleton of SMA. To verify the laboratory test results, gradation analysis was also conducted for the field materials extracted from SMA pavements after long-time service. The results indicate that the degradation of SMA aggregate skeleton is not random but has fixed internal trend and mechanism. Special rule is found for the graded fine aggregates generated from coarse aggregate breakdown and the variation of 4.75 mm aggregate is found to play a key role in the graded aggregates to form well-balanced skeleton to bear external loading. The variation of 4.75 mm aggregate together with the breakdown ratio of aggregate gradation can be used to characterize the degradation behavior of aggregate skeleton. The crushing test and SGC test are proved to be promising in estimating the degradation behavior of SMA skeleton.
基金Project(50578038)supported by the National Natural Science Foundation of China
文摘Crack is found to be a major distress that affects the performance of the epoxy asphalt pavement.An extended finite element method was proposed for investigating the fracture properties of the epoxy asphalt mixture.Firstly,the single-edge notched beam test was used to analyze the temperature effect and calculate the material parameters.Then,the mechanical responses were studied using numerical analysis.It is concluded that 5℃ can be selected as the critical temperature that affects the fracture properties,and numerical simulations indicate that crack propagation is found to significantly affect the stress state of the epoxy asphalt mixture.The maximum principal stress at the crack surface exhibits different trends at various temperatures.Numerical solution of stress intensity factor can well meet the theoretical solution,especially when the temperature is lower than 5℃.
文摘A research project was initiated by INDOT to estimate the structural contribution and feasibility of FDR bases for pavement structure under a low-medium volume traffic loading. FWD tests were conducted and the layer moduli were back calculated on different construction phases： the surface of existing HMA pavement, the FDR base, the new HMA final surface, and the nine months＇ traffic opening, respectively, for a total of four times. The results indicate the promise of this recycled base material in pavement construction compared to traditional granular base. In addition, this paper discusses how the lab test results relate to the expected performance in a pavement structure by the MEPDG software and its parameter effects. Research indicated the MEPDG provided comparable thickness to the 1993 AASHTO Guide if the failure criteria are set up reasonably. Therefore, the MEPDG could be used as a design tool to estimate layer thickness for FDR pavement with a low-medium traffic volume.
