The ice melting performance of three types of deicers, including sodium chloride, calcium chloride and sodium acetate, were tested in laboratory under different temperature conditions, and their effects on asphalt mix...The ice melting performance of three types of deicers, including sodium chloride, calcium chloride and sodium acetate, were tested in laboratory under different temperature conditions, and their effects on asphalt mixture were evaluated from the point of the stripping resistance of asphalt mixture. Unsaturated Marshall samples were exposed to freeze-thaw cycling while immersed in the deicer solutions of different concentrations. After the freeze-thaw cycles, Cantabro tests were performed, and Cantabro loss was adopted to characterize the stripping resistance of asphalt mixture. The test results show that calcium chloride has the best comprehensive ice melting performance, and all deicers have detrimental effect on the stripping resistance of asphalt mixture at different degrees. The damage degree depends on deicer types and their concentration in the solution. Deicer solutions with about 2% concentration cause the greatest loss of stripping resistance due to serious freeze-thaw damage. Sodium acetate causes greater loss of stripping resistance than sodium chloride and calcium chloride at the same concentration.展开更多
Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and...Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and dust may negatively influence organisms in downstream receiving water bodies. The present work focuses on the impact of road salt（NaCl） and Cu, separately and in mixtures on Atlantic salmon alevins from hatching till swim-up. The results showed that high road salt concentrations could induce a series of negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality. For alevins exposed to all tested road salt concentrations（100–1000 mg/L）,mortality was significantly higher compared to control. In exposure to Cu solutions（5–20 μg Cu/L）, no effects on growth, morphology, swim-up or mortality of alevins compared to control were observed. In mixture solutions（road salt and Cu）, ultrafiltration of the exposure water demonstrated that only 20%–40% of Cu was present as positively charged low molecular mass（LMM） Cu species assumed to be bioavailable. When exposed to road salt and Cu mixtures, negative effects in alevins such as reduced growth, deformities,delayed swim-up and mortality were observed. The overall results indicated that the road salt application could seriously affect sensitive life stages of Atlantic salmon, and application of road salt should be avoided during the late winter–early spring period.展开更多
Stormwater runoff at airports is a significant and costly issue, especially for the stormwater laden with deicing contaminants of high Biochemical Oxygen Demand （BOD） and aquatic toxicity. To reduce the loading of d...Stormwater runoff at airports is a significant and costly issue, especially for the stormwater laden with deicing contaminants of high Biochemical Oxygen Demand （BOD） and aquatic toxicity. To reduce the loading of deicing constituents in stormwater and to manage the increasing pressure of tightening regulations, identifying fate and transport and evaluating environmental risks of deicing stormwater are of critical importance. In this review, the regulatory development of airport deicing stormwater management was first discussed, along with the milestone Airport Cooperative Research Program （ACRP） Report 14 publication. The deicer usage and fugitive losses can be reduced and the amount of deicer collected can be increased by having a better understanding of the fate and transport of deicing constituents in stormwater. As such, an overview and evaluation of the constituents of concern in deicers were provided to support the assessment of environmental impacts and mitigation recommendations. The state of knowledge of airport deicing stormwater management was then reviewed, which needs to be synthesized into a national guidance document. A guidebook and a decision tool for airports were proposed to adopt specific practical stormwater management strategies while balancing their priorities in environmental, economic, and social values against operational constraints. These challenges pose great opportunities to improve the current practices of airport deicing stormwater management.展开更多
The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete（HPC）is investigated.Freeze-thaw durability of HPC is tested by accel...The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete（HPC）is investigated.Freeze-thaw durability of HPC is tested by accelerated freeze-thaw test.Four kinds of the solution,i.e.,tap water,3.5% NaCl solution,glycol solutions,and a LBR-A type commercial aircraft deicer are employed.Results show that freeze-thaw durability of HPC exposed to glycol solutions is closely related to the solution concentrations.The failure of HPC exposed to 3.5% glycol solution is similar to that of those exposed to 3.5% NaCl solution,i.e.,serious surface scaling.While the damage of HPC exposed to 12.5%—25% glycol solutions is postponed.Compared with glycol solution,the commercial aircraft deicer has much more negative effects on HPC freeze-thaw durability compared with 3.5% NaCl solution.In the presence of commercial aircraft deicer for HPC subjected to freeze-thaw cycles,the deterioration is mainly due to scaling and spalling.展开更多
Salt-storage anti-icing ultra-thin friction courses(SAUTFC) are an effective preventive maintenance treatment to improve road performance and ensure the safety of winter pavement traffic. However, the addition of salt...Salt-storage anti-icing ultra-thin friction courses(SAUTFC) are an effective preventive maintenance treatment to improve road performance and ensure the safety of winter pavement traffic. However, the addition of salt storage agents and precipitates decreases the engineering and anti-icing performance. Hence, this study used the temperaturecontrolled salt-controlled-release deicer(SCD) to prepare and characterize SAUTFC. The microstructure and properties of SCD were investigated. The SAUTFC preparation procedures and content of SCD were determined. Subsequently, the interlayer bonding properties, skid resistance performance, and anti-freeze properties were evaluated. The results indicated that SCD with a glass transition temperature of-4℃ can control the precipitation of salts before the winter. The SCD dosing in SAUTFC is 75% of the replacement mineral powder, and interlayer shear strength reaches its maximum when the application rate of the tack coat is 1 kg/m2. The wear resistance of SAUTFC was investigated by accelerated loading tests, which showed that SAUTFC still provides excellent skid resistance after four years. In addition, the SAUTFC accelerates the melting rate of snow and ice and decreases the bonding force between ice and the specimen surface, with excellent anti-freeze durability. Therefore, the application of salt storage materials in ultrathin friction courses to provide active snow and ice removal on winter pavements is feasible.展开更多
The bamboo vinegar was used to produce organic calcium,and different concentrations of NaCl,CaCb and organic calcium solutions as deicer were sprayed evenly on the potted Cymbidium ensifoiium and collected soil, and t...The bamboo vinegar was used to produce organic calcium,and different concentrations of NaCl,CaCb and organic calcium solutions as deicer were sprayed evenly on the potted Cymbidium ensifoiium and collected soil, and the growth of C.ensifoiium was observed everyday,and the physical and chemical properties of soil were analyzed.The results indicate that all the 3 types of salt solutions had certain influence on C.ensifolium,while the organic calcium had less effect on C.ensifolium than NaCl and CaCl<sub>2</sub>,and both of NaCl and CaCl<sub>2</sub> had little effect on the pH of soil while organic calcium increased greatly the pH of soil,and the organic matter and cationic exchange capacity of soil reduced,and the content of total N, P in soil also reduced while the apparent content of total K in soil increased.By above comparison,the effect of organic calcium made by bamboo vinegar on C.ensifolium and soil was less than that of NaCl and CaCl<sub>2</sub>,in addition smaller the concentration of salt solution was,less the effect of salt solution on C.ensifoliumand soil was.展开更多
基金The Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20120092110053)
文摘The ice melting performance of three types of deicers, including sodium chloride, calcium chloride and sodium acetate, were tested in laboratory under different temperature conditions, and their effects on asphalt mixture were evaluated from the point of the stripping resistance of asphalt mixture. Unsaturated Marshall samples were exposed to freeze-thaw cycling while immersed in the deicer solutions of different concentrations. After the freeze-thaw cycles, Cantabro tests were performed, and Cantabro loss was adopted to characterize the stripping resistance of asphalt mixture. The test results show that calcium chloride has the best comprehensive ice melting performance, and all deicers have detrimental effect on the stripping resistance of asphalt mixture at different degrees. The damage degree depends on deicer types and their concentration in the solution. Deicer solutions with about 2% concentration cause the greatest loss of stripping resistance due to serious freeze-thaw damage. Sodium acetate causes greater loss of stripping resistance than sodium chloride and calcium chloride at the same concentration.
文摘Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and dust may negatively influence organisms in downstream receiving water bodies. The present work focuses on the impact of road salt（NaCl） and Cu, separately and in mixtures on Atlantic salmon alevins from hatching till swim-up. The results showed that high road salt concentrations could induce a series of negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality. For alevins exposed to all tested road salt concentrations（100–1000 mg/L）,mortality was significantly higher compared to control. In exposure to Cu solutions（5–20 μg Cu/L）, no effects on growth, morphology, swim-up or mortality of alevins compared to control were observed. In mixture solutions（road salt and Cu）, ultrafiltration of the exposure water demonstrated that only 20%–40% of Cu was present as positively charged low molecular mass（LMM） Cu species assumed to be bioavailable. When exposed to road salt and Cu mixtures, negative effects in alevins such as reduced growth, deformities,delayed swim-up and mortality were observed. The overall results indicated that the road salt application could seriously affect sensitive life stages of Atlantic salmon, and application of road salt should be avoided during the late winter–early spring period.
文摘Stormwater runoff at airports is a significant and costly issue, especially for the stormwater laden with deicing contaminants of high Biochemical Oxygen Demand （BOD） and aquatic toxicity. To reduce the loading of deicing constituents in stormwater and to manage the increasing pressure of tightening regulations, identifying fate and transport and evaluating environmental risks of deicing stormwater are of critical importance. In this review, the regulatory development of airport deicing stormwater management was first discussed, along with the milestone Airport Cooperative Research Program （ACRP） Report 14 publication. The deicer usage and fugitive losses can be reduced and the amount of deicer collected can be increased by having a better understanding of the fate and transport of deicing constituents in stormwater. As such, an overview and evaluation of the constituents of concern in deicers were provided to support the assessment of environmental impacts and mitigation recommendations. The state of knowledge of airport deicing stormwater management was then reviewed, which needs to be synthesized into a national guidance document. A guidebook and a decision tool for airports were proposed to adopt specific practical stormwater management strategies while balancing their priorities in environmental, economic, and social values against operational constraints. These challenges pose great opportunities to improve the current practices of airport deicing stormwater management.
基金Supported by the National Basic Research Program of China("973"Program)(2009CB623203)the China Postdoctoral Science Foundation(20070421036)+1 种基金the Natural Science Foundation of Jiangsu Province(BK2005216)the Research Foundation of Nanjing University of Aeronautics and Astronautics(NS2010015)~~
文摘The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete（HPC）is investigated.Freeze-thaw durability of HPC is tested by accelerated freeze-thaw test.Four kinds of the solution,i.e.,tap water,3.5% NaCl solution,glycol solutions,and a LBR-A type commercial aircraft deicer are employed.Results show that freeze-thaw durability of HPC exposed to glycol solutions is closely related to the solution concentrations.The failure of HPC exposed to 3.5% glycol solution is similar to that of those exposed to 3.5% NaCl solution,i.e.,serious surface scaling.While the damage of HPC exposed to 12.5%—25% glycol solutions is postponed.Compared with glycol solution,the commercial aircraft deicer has much more negative effects on HPC freeze-thaw durability compared with 3.5% NaCl solution.In the presence of commercial aircraft deicer for HPC subjected to freeze-thaw cycles,the deterioration is mainly due to scaling and spalling.
基金supported by the Chongqing Technology Innovation and Application Development Special Key Project(CSTB2022TIAD-KPX0203)Chongqing Talent Innovation Demonstration Team(CQYC202203091112)Joint Training Base Construction Project for Graduate Students in Chongqing(JDLHPYJD2020013,JDLHPYJD2021010).
文摘Salt-storage anti-icing ultra-thin friction courses(SAUTFC) are an effective preventive maintenance treatment to improve road performance and ensure the safety of winter pavement traffic. However, the addition of salt storage agents and precipitates decreases the engineering and anti-icing performance. Hence, this study used the temperaturecontrolled salt-controlled-release deicer(SCD) to prepare and characterize SAUTFC. The microstructure and properties of SCD were investigated. The SAUTFC preparation procedures and content of SCD were determined. Subsequently, the interlayer bonding properties, skid resistance performance, and anti-freeze properties were evaluated. The results indicated that SCD with a glass transition temperature of-4℃ can control the precipitation of salts before the winter. The SCD dosing in SAUTFC is 75% of the replacement mineral powder, and interlayer shear strength reaches its maximum when the application rate of the tack coat is 1 kg/m2. The wear resistance of SAUTFC was investigated by accelerated loading tests, which showed that SAUTFC still provides excellent skid resistance after four years. In addition, the SAUTFC accelerates the melting rate of snow and ice and decreases the bonding force between ice and the specimen surface, with excellent anti-freeze durability. Therefore, the application of salt storage materials in ultrathin friction courses to provide active snow and ice removal on winter pavements is feasible.
文摘The bamboo vinegar was used to produce organic calcium,and different concentrations of NaCl,CaCb and organic calcium solutions as deicer were sprayed evenly on the potted Cymbidium ensifoiium and collected soil, and the growth of C.ensifoiium was observed everyday,and the physical and chemical properties of soil were analyzed.The results indicate that all the 3 types of salt solutions had certain influence on C.ensifolium,while the organic calcium had less effect on C.ensifolium than NaCl and CaCl<sub>2</sub>,and both of NaCl and CaCl<sub>2</sub> had little effect on the pH of soil while organic calcium increased greatly the pH of soil,and the organic matter and cationic exchange capacity of soil reduced,and the content of total N, P in soil also reduced while the apparent content of total K in soil increased.By above comparison,the effect of organic calcium made by bamboo vinegar on C.ensifolium and soil was less than that of NaCl and CaCl<sub>2</sub>,in addition smaller the concentration of salt solution was,less the effect of salt solution on C.ensifoliumand soil was.
