The research considered urgent ecological reasons linked to environment such as worn tires, the waste tire rubber＇s powder was collected from the tire cars repair shops （passed from the sieve No 18 μm）, and used t...The research considered urgent ecological reasons linked to environment such as worn tires, the waste tire rubber＇s powder was collected from the tire cars repair shops （passed from the sieve No 18 μm）, and used to improve the asphalt concrete properties. Raw materials used were prepared and tested. Varies of asphalt concrete mixtures were prepared with different ratios of bitumen （5, 5.5, 6, 6.5, 7% % of concrete weight）. The Marshall mix design method was used to determine optimum conditions for bitumen in asphalt concrete with specific weight, stability and flow Test, the optimum amount of bitumen was 6.1% of whole asphalt concrete. The different percentages of waste tire rubber powder （0.0, 0.05, 0.10, 0.15% of bitumen weight） were added in optimum bitumen of asphalt concretes, then specific weight and Marshall test were evaluated. These asphalt-rubber mixtures were found to act quite differently from traditional, unmodified asphalt mixtures. However, these results indicate that improved pavement performance can be achieved with asphalt-rubber binder.展开更多
The Arizona Department of Transportation （ADOT） in the USA conducted a series of asphalt aging related research and special studies between the 1970s and 1990s. The studies covered over 157 test sections representin...The Arizona Department of Transportation （ADOT） in the USA conducted a series of asphalt aging related research and special studies between the 1970s and 1990s. The studies covered over 157 test sections representing both neat （virgin） asphalt and crumb rubber modified （asphalt-rubber） binders. The data comprised of a wide range of penetration, viscosity, and Performance Grade （PG） parameters, at original and aged conditions. In the late 1990s, asphalt PG complex shear modulus （G＊）, and phase angle （5） data were collected. The main purpose of this paper was to use the assembled database of the field core-aged asphalt test data and compare the test results to the American Association of State Highway and Transportation Officials approved Mechanistic-Empirical Pavement Design Guide （MEPDG） predictive modeled asphalt properties such as penetration and viscosity, G＊, and 5. Furthermore, G＊ and laboratory measurements on neat and asphalt-rubber binders extracted from the field cores of the pavement sections aged ten or more years were compared to the pressure aging vessel PG G＊ and ~. values. It was observed that the MEPDG predicted asphalt binder properties were rational for originally （tank） sampled binders, but fairly correlated for the aged binders. Additionally, penetration and viscosity aging indices representing over 20 years of field aged sections were established for a wide variety of asphalt binder grades. Overall, the relationships for aging indices were meaningful and rational. Results of this research indicated the degree of difficulty in predicting asphalt binder properties for pavements with ten or more years of field aging. The findings from this research study are envisioned to be of substantial value in future asphalt binder aging studies.展开更多
文摘The research considered urgent ecological reasons linked to environment such as worn tires, the waste tire rubber＇s powder was collected from the tire cars repair shops （passed from the sieve No 18 μm）, and used to improve the asphalt concrete properties. Raw materials used were prepared and tested. Varies of asphalt concrete mixtures were prepared with different ratios of bitumen （5, 5.5, 6, 6.5, 7% % of concrete weight）. The Marshall mix design method was used to determine optimum conditions for bitumen in asphalt concrete with specific weight, stability and flow Test, the optimum amount of bitumen was 6.1% of whole asphalt concrete. The different percentages of waste tire rubber powder （0.0, 0.05, 0.10, 0.15% of bitumen weight） were added in optimum bitumen of asphalt concretes, then specific weight and Marshall test were evaluated. These asphalt-rubber mixtures were found to act quite differently from traditional, unmodified asphalt mixtures. However, these results indicate that improved pavement performance can be achieved with asphalt-rubber binder.
文摘The Arizona Department of Transportation （ADOT） in the USA conducted a series of asphalt aging related research and special studies between the 1970s and 1990s. The studies covered over 157 test sections representing both neat （virgin） asphalt and crumb rubber modified （asphalt-rubber） binders. The data comprised of a wide range of penetration, viscosity, and Performance Grade （PG） parameters, at original and aged conditions. In the late 1990s, asphalt PG complex shear modulus （G＊）, and phase angle （5） data were collected. The main purpose of this paper was to use the assembled database of the field core-aged asphalt test data and compare the test results to the American Association of State Highway and Transportation Officials approved Mechanistic-Empirical Pavement Design Guide （MEPDG） predictive modeled asphalt properties such as penetration and viscosity, G＊, and 5. Furthermore, G＊ and laboratory measurements on neat and asphalt-rubber binders extracted from the field cores of the pavement sections aged ten or more years were compared to the pressure aging vessel PG G＊ and ~. values. It was observed that the MEPDG predicted asphalt binder properties were rational for originally （tank） sampled binders, but fairly correlated for the aged binders. Additionally, penetration and viscosity aging indices representing over 20 years of field aged sections were established for a wide variety of asphalt binder grades. Overall, the relationships for aging indices were meaningful and rational. Results of this research indicated the degree of difficulty in predicting asphalt binder properties for pavements with ten or more years of field aging. The findings from this research study are envisioned to be of substantial value in future asphalt binder aging studies.
