The consistency of the ethanol foamed binders and mixtures prepared using asphalt binders foamed by the manual injection technique and laboratory foaming device were evaluated and compared in this study. The asphalt b...The consistency of the ethanol foamed binders and mixtures prepared using asphalt binders foamed by the manual injection technique and laboratory foaming device were evaluated and compared in this study. The asphalt binders foamed using both methods was prepared at 120℃, 130℃ and 140℃. The performance of ethanol-foamed binders was evaluated in terms of rotational viscosity, expansion ratio, and low temperature cracking.Meanwhile, the performance of foamed WMA mixtures was tested using semi-circular bending(SCB), disk-shaped compact tension(DCT), and tensile strength ratio(TSR) tests. In order to conduct the TSR test, the samples were conditioned using the Moisture Induced Stress Tester(MIST) to simulate the pore pressure and scouring effects due to a tire passing over wet pavement. The foamed WMA mixtures were produced using pre-heated aggregates at 80℃ and 100℃ and foamed asphalt binders produced at 130℃. The nano-hydrated lime was used as the filler and anti-stripping agent. Overall, the properties of ethanol-foamed binders and WMA mixtures produced via both methods are significantly comparable, except the resistance to moisture damage test result. However, the findings indicate that the ethanol-foamed WMA mixtures prepared using both techniques are having good resistance to moisture damage, based on the TSR values more than 0.8. The foamed WMA mixtures also exhibited a better resistance to cracking, as indicated by a higher tensile strength compared to the control HMA. Additionally, the WMA specimen prepared at 100℃ was less susceptible to rutting than the samples produced at 80℃.展开更多
The highway construction industry plays an important role in economic and development, but is also a primary source of carbon emission. Accordingly, with the global climate change, energy conservation and reduction of...The highway construction industry plays an important role in economic and development, but is also a primary source of carbon emission. Accordingly, with the global climate change, energy conservation and reduction of carbon emissions have become critical is- sues in the highway construction industry. However, to date, a model for the highway construction industry has not been established. Hence, to implement a low-carbon con- struction model for highways, this study divided asphalt pavement construction into aggregate stacking, aggregate supply, and other stages, and compiled a list of energy consumption investigation. An appropriate calculation model of CO2 emission was then built. Based on the carbon emission calculation model, the proportion of carbon emissions in each stage was analyzed. The analytic hierarchy process was used to establish the system of asphalt pavement construction with a judgment matrix, thereby enabling calculation of the weight coefficient of each link. In addition, the stages of aggregate heating, asphalt heating, and asphalt mixture mixing were defined as key stages of asphalt pavement construction. Carbon emissions at these stages accounted for approximately 90% of the total carbon emissions. Carbon emissions at each stage and their impact on the environment were quantified and compared. The energy saving construction schemes as well as the environmental and socioeconomic benefits were then proposed. Through these schemes, significant reductions in carbon emissions and costs can be achieved. The results indicate that carbon emissions reduce by 32.30% and 35.93%, whereas costs reduce by 18.58% and 6.03%. The proposed energy-saving and emission reduction scheme can pro- vide a theoretical basis and technical support for the development of low-carbon highway construction.展开更多
基金the U.S. National Science Foundation which funded a research grant through SusChEM/Collaborative Research program (Award Number: 1300286) and enabled this study to be completed
文摘The consistency of the ethanol foamed binders and mixtures prepared using asphalt binders foamed by the manual injection technique and laboratory foaming device were evaluated and compared in this study. The asphalt binders foamed using both methods was prepared at 120℃, 130℃ and 140℃. The performance of ethanol-foamed binders was evaluated in terms of rotational viscosity, expansion ratio, and low temperature cracking.Meanwhile, the performance of foamed WMA mixtures was tested using semi-circular bending(SCB), disk-shaped compact tension(DCT), and tensile strength ratio(TSR) tests. In order to conduct the TSR test, the samples were conditioned using the Moisture Induced Stress Tester(MIST) to simulate the pore pressure and scouring effects due to a tire passing over wet pavement. The foamed WMA mixtures were produced using pre-heated aggregates at 80℃ and 100℃ and foamed asphalt binders produced at 130℃. The nano-hydrated lime was used as the filler and anti-stripping agent. Overall, the properties of ethanol-foamed binders and WMA mixtures produced via both methods are significantly comparable, except the resistance to moisture damage test result. However, the findings indicate that the ethanol-foamed WMA mixtures prepared using both techniques are having good resistance to moisture damage, based on the TSR values more than 0.8. The foamed WMA mixtures also exhibited a better resistance to cracking, as indicated by a higher tensile strength compared to the control HMA. Additionally, the WMA specimen prepared at 100℃ was less susceptible to rutting than the samples produced at 80℃.
基金supported by Natural Science Foundation of Shaanxi Province (2011JM7001)Communications Scientific Research Project of Gansu Province (201227)
文摘The highway construction industry plays an important role in economic and development, but is also a primary source of carbon emission. Accordingly, with the global climate change, energy conservation and reduction of carbon emissions have become critical is- sues in the highway construction industry. However, to date, a model for the highway construction industry has not been established. Hence, to implement a low-carbon con- struction model for highways, this study divided asphalt pavement construction into aggregate stacking, aggregate supply, and other stages, and compiled a list of energy consumption investigation. An appropriate calculation model of CO2 emission was then built. Based on the carbon emission calculation model, the proportion of carbon emissions in each stage was analyzed. The analytic hierarchy process was used to establish the system of asphalt pavement construction with a judgment matrix, thereby enabling calculation of the weight coefficient of each link. In addition, the stages of aggregate heating, asphalt heating, and asphalt mixture mixing were defined as key stages of asphalt pavement construction. Carbon emissions at these stages accounted for approximately 90% of the total carbon emissions. Carbon emissions at each stage and their impact on the environment were quantified and compared. The energy saving construction schemes as well as the environmental and socioeconomic benefits were then proposed. Through these schemes, significant reductions in carbon emissions and costs can be achieved. The results indicate that carbon emissions reduce by 32.30% and 35.93%, whereas costs reduce by 18.58% and 6.03%. The proposed energy-saving and emission reduction scheme can pro- vide a theoretical basis and technical support for the development of low-carbon highway construction.
