De-icing Chemicals Research Articles

교통량 및 제설제 사용량에 따른 고속도로 포장의 공용수명 분석

PURPOSES : The purpose of this study is to analyze the service life of expressway pavement based on both traffic volumes and use of deicing chemicals. METHODS : A database was built using expressway rehabilitation history information from over the last decade. In order to estimate the service life of expressway pavement, various analysis methods were considered, and a decision was made to perform analysis using a method based on an accumulated rehabilitation ratio. The service life of expressway pavement was then analyzed by classifying the scale of traffic volume and extent of de-icing chemicals used. RESULTS : The service life of PMA and SMA ranged from 7.8 to 10.6 years and from 9.9 to 12.0 years, respectively. The service life of JCP ranged from 16.0 to 22.2 years, and the service life of CRCP was 33.5 years on average. Results of assessing service life according to traffic volumes and de-icing chemicals showed that the lower the traffic volumes were, the greater the service life of PMA and JCP, and the less that de-icing chemicals were applied, the greater the service life of JCP. CONCLUSIONS : The dependence of expressway pavement service life on traffic volumes and de-icing chemicals makes it possible to apply LCCA for regional maintenance plans and cost-effective selection of expressway pavement type.

The effect of common de-icing chemicals on the hardness of compacted snow

Chemicals are commonly used in winter maintenance to prevent ice and snow from compacting on roads and runways. A recent study has shown that one important mechanism through which chemicals act is that the presence of a solution weakens the bonding between snow crystals. It is, however, not clear whether the weakened bonding comes from the introduction of liquid solution into the snow or if it is related to the dissolved chemicals. This was examined by mixing dendritic snow with six different solutions in equilibrium with ice. The mixture was compressed and the hardness of the resulting snow compact was measured. The dissolved chemical had a significant effect on snow hardness. Snow mixed with the most efficient chemical, potassium formate, was 25% softer than snow mixed with sodium chloride. Urea produced snow 20% harder than sodium chloride. The effect in practice could be substantial. To achieve the same snow hardness, only a third of the solution volume would be needed if potassium formate was used instead of sodium chloride.

Corrosion of cadmium plating by runway de-icing chemicals in cyclic tests: Effects of chemical concentration and plating quality

Concentration of de-icing chemicals used at airfields in Northern countries may vary significantly, due to the dilution caused by rain and melting ice or snow. Furthermore, quality variations in cadmium platings used in aircraft components are a common fact. In this study, we examine the influence of the de-icing chemical concentration and the plating quality on the corrosion of cadmium using two cyclic corrosion tests: Boeing and AMS G-12 tests. The tests are performed using four de-icers: pure potassium formate, pure potassium acetate and two commercial chemicals containing these salts, at three concentrations, and four types of cadmium plating.The obtained results show that the extent of corrosion of the cadmium plating decreases with decrease in de-icing chemical concentration. The changes in characteristics of the chemicals, such as pH value, electrical conductivity and the amount of dissolved oxygen, due to changes in concentration, do not unambiguously explain the observation. Rather, the conditions during heat–humidity exposure, particularly the employed temperature, are of key importance. Wetting behavior of the chemicals on the four types of cadmium plating discloses slight differences between the plating types but more distinct differences between the used potassium formates and potassium acetates. A more efficient wetting of cadmium platings by potassium formates than potassium acetates yields one explanation why potassium formates introduce more severe corrosion damage. Concerning the cadmium plating quality, thickness and the amount and distribution of pores are the key parameters in terms of corrosion performance. In this paper, these results are presented and discussed in the light of published literature.

A Student-Based Investigation to Assess the Impacts of Chemical Deicers on the Water Quality of Spring Run Stream in Altoona, Pennsylvania

ABSTRACT Students in an undergraduate independent study course at Penn State Altoona investigated the use and potential effects of chemical deicers on the water quality of the stream that runs through the campus. Spring Run supports a wild trout population and is a tributary of the Little Juniata River and a headwater stream for the Chesapeake Bay watershed. Students collected pre- and post- chemical deicer application water samples from Spring Run stream over four sampling dates. Water samples were analyzed for potassium (K+), sodium (Na+), dissolved oxygen, pH, chloride (Cl−) and ammonia as nitrogen (NH3−). None of the parameters sampled exceeded the standard guidelines for the protection of aquatic life. However, this study found cause for future research, particularly as it relates to the concentration of chloride in stream water. Chloride exhibited significant increases in concentration between pre- and post-deicer application. With the exception of one sampling date, chloride concentrations (19.2–63.7 mg/L) fell within the range of concentrations found in streams in the northeast United States that have been contaminated by rock salt inputs. The learning outcomes and skill development objectives of this field-intensive experience were driven by the assumption that this type of field-based educational experience enhances student learning by contextualizing complex geographical processes better than a solely classroom-based experience. Through the research process students were exposed to working with field techniques, GPS, GIS, datasets and statistics.

Improved management of winter operations to limit subsurface contamination with degradable deicing chemicals in cold regions

This paper gives an overview of management considerations required for better control of deicing chemicals in the unsaturated zone at sites with winter maintenance operations in cold regions. Degradable organic deicing chemicals are the main focus. The importance of the heterogeneity of both the infiltration process, due to frozen ground and snow melt including the contact between the melting snow cover and the soil, and unsaturated flow is emphasised. In this paper, the applicability of geophysical methods for characterising soil heterogeneity is considered, aimed at modelling and monitoring changes in contamination. To deal with heterogeneity, a stochastic modelling framework may be appropriate, emphasizing the more robust spatial and temporal moments. Examples of a combination of different field techniques for measuring subsoil properties and monitoring contaminants and integration through transport modelling are provided by the SoilCAM project and previous work. Commonly, the results of flow and contaminant fate modelling are quite detailed and complex and require post-processing before communication and advising stakeholders. The managers' perspectives with respect to monitoring strategies and challenges still unresolved have been analysed with basis in experience with research collaboration with one of the case study sites, Oslo airport, Gardermoen, Norway. Both scientific challenges of monitoring subsoil contaminants in cold regions and the effective interaction between investigators and management are illustrated.

Degradation of deicing chemicals affects the natural redox system in airfield soils

During winter operations at airports, large amounts of organic deicing chemicals (DIC) accumulate beside the runways and infiltrate into the soil during spring. To study the transport and degradation of DIC in the unsaturated zone, eight undisturbed soil cores were retrieved at Oslo airport, Norway, and installed as lysimeters at a nearby field site. Before snowmelt in 2010 and 2011, snow amended with a mix of the DICs propylene glycol (PG) and formate as well as bromide as conservative tracer was applied. Water samples were collected and analyzed until summer 2012. Water flow and solute transport varied considerably among the lysimeters but also temporally between 2010 and 2011. High infiltration rates during snowmelt resulted in the discharge of up to 51 and 82% PG in 2010 and 2011, respectively. The discharge of formate remained comparatively low, indicating its favored degradation even at freezing temperatures compared with PG. Manganese (Mn) and iron (Fe) were observed in the drainage in autumn owing to the anaerobic degradation of residual PG during summer. Our findings suggest that upper boundary conditions, i.e., snow cover and infiltration rate, and the extent of preferential flowpaths, control water flow and solute transport of bromide and PG during snowmelt. PG may therefore locally reach deeper soil regions where it may pose a risk for groundwater. In the long term, the use of DIC furthermore causes the depletion of potential electron acceptors and the transport of considerable amounts of Fe and Mn. To avoid an overload of the unsaturated zone with DIC and to maintain the natural redox system, the development of suitable remediation techniques is required.

Transport and degradation of propylene glycol in the vadose zone: model development and sensitivity analysis

Transport and degradation of de-icing chemical (containing propylene glycol, PG) in the vadose zone were studied with a lysimeter experiment and a model, in which transient water flow, kinetic degradation of PG and soil chemistry were combined. The lysimeter experiment indicated that aerobic as well as anaerobic degradation occurs in the vadose zone. Therefore, the model included both types of degradation, which was made possible by assuming advection-controlled (mobile) and diffusion-controlled (immobile) zones. In the mobile zone, oxygen can be transported by diffusion in the gas phase. The immobile zone is always water-saturated, and oxygen only diffuses slowly in the water phase. Therefore, the model is designed in a way that the redox potential can decrease when PG is degraded, and thus, anaerobic degradation can occur. In our model, manganese oxide (MnO2, which is present in the soil) and NO3- (applied to enhance biodegradation) can be used as electron acceptors for anaerobic degradation. The application of NO3- does not result in a lower leaching of PG nor in a slower depletion of MnO2. The thickness of the snowcover influences the leached fraction of PG, as with a high infiltration rate, transport is fast, there is less time for degradation and thus more PG will leach. The model showed that, in this soil, the effect of the water flow dominates over the effect of the degradation parameters on the leaching at a 1-m depth.

Corrosion of cadmium plating by runway de-icing chemicals: Study of surface phenomena and comparison of corrosion tests

In this paper, we study the corrosion of cadmium plating by four runway de-icing chemicals using electrochemical measurements and standard (immersion) and proposed (cyclic) runway de-icing corrosion tests for cadmium plating. Besides the obtained electrochemical and gravimetric data, we analyze the exposed surfaces by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and infra-red spectroscopy (IR). The chemicals included in the tests are pure potassium formate, pure potassium acetate and the corresponding commercial chemicals.Examinations revealed two parallel and linked phenomena on the plating surface, i.e., anodic dissolution of cadmium and development of corrosion products, primarily cadmium carbonate, CdCO3. Electrochemical measurements disclosed that the formed corrosion products slightly improved corrosion resistance of the surface but definitely did not stop corrosion completely, probably due to discontinuous structure. As for the studied de-icing chemicals, potassium formates systematically introduced more segmented corrosion products than potassium acetates and, subsequently, more severe corrosion on the specimens. Immersion cadmium corrosion test did not give very reliable results due to relatively low introduced corrosion rates and very large occasional scatter in the results. Cyclic cadmium corrosion tests introduced relatively greater corrosion rates and somewhat lower deviations than the immersion test, being hence, more reliable, but also more challenging in terms of meeting the weight change criteria for passing the test.

Evaluation of Ice-Melting Capacities of Deicing Chemicals

Abstract Common deicing chemicals include sodium chloride, magnesium chloride, calcium chloride, calcium magnesium acetate, potassium acetate, potassium formate, and corn or beet-based deicer solution. Liquid deicers are commonly used for pre-wetting road salt, sand or other solid deicers, or mixed with salt brine as liquid deicer. Although manufacturers provide performance data under specific conditions, a standardized test is very much needed. Samples of sodium chloride, magnesium chloride, calcium chloride, potassium acetate, and beet juice-based chemical deicers were selected for performance evaluation. The SHRP Ice-Melting Capacity Test has been used in many research projects, but the results do not always correlate well with field data. A simple and economical test has been developed to evaluate the ice-melting capacities of deicing chemicals using a martini shaker, which shows some potential to become a standardized test for ice-melting capacity evaluation. Field data was collected by the Nebraska Dept. of Roads using automatic vehicle location (AVL) and the maintenance decision support system (MDSS) installed on some plow trucks. The AVL takes roadway pictures from the cab and records vehicle location. The MDSS collects weather data from area weather stations. Although initial shaker test results correlate well with known deicer performance and limited field data provided by MDSS, further development work is necessary before the shaker test can be considered for official use.

Evaluation on the Effects of Deicing Chemicals on Soil and Water Environment

Abstract Deicing chemicals are widely used to clear the pavement snow in the cold areas of China and many other countries in winter, because of their simple operation and excellent snow-melting effect, which leads to more convenience for traffic and low probability of traffic accident in the city, especially in metropolis. However, with the ever-growing application of deicing chemicals, their negative effects on environment such as soil and water system increased dramatically. Based on the related researches in China and abroad, this paper summarized the two categories of deicing chemicals and their working principles, and then provided the unique characteristics of deicing chemicals’ effects on soil and water environment in large cities, which may need considerable quantity of the chemicals to relieve traffic congestion. What's more, main aspects of impacts by deicing chemicals on regional soil and water environment and the fundamental factors related to the aspects above respectively were generalized, in order to propose a conceptual model to evaluate the harmful effects. Moreover, this paper put forward some suggestions for the further research in this field to fulfill the model, and provided a scientific basis for the pollution prevention of deicing chemicals on urban environment.

Effects of six chemical deicers on larval wood frogs (Rana sylvatica)

Widespread and intensive application of road deicers, primarily road salt (NaCl), in North America threatens water quality and the health of freshwater ecosystems. Intensive use of NaCl can be harmful to sensitive members of freshwater ecosystems such as amphibians. Detection of negative effects of NaCl application has prompted the search for alternative chemical deicers with lower environmental impacts. We conducted a series of 96-h acute toxicity tests to determine the negative sensitivity of larval wood frogs (Rana [Lithobates] sylvatica) to six deicing chemicals: urea (CH(4) N(2) O), sodium chloride (NaCl), magnesium chloride (MgCl(2) ), potassium acetate (CH(3) COOK), calcium chloride (CaCl(2) ), and calcium magnesium acetate (C(8) H(12) CaMgO(8) ). Acetates are sometimes touted as environmentally friendly alternatives to NaCl but have not been examined in enough detail to warrant this designation. When exposed to a range of environmentally realistic concentrations of these chemicals, larvae were least sensitive (i.e., had the lowest mortality rate) to CH(4) N(2) O, NaCl, and MgCl(2) and most sensitive to acetates (C(8) H(12) CaMgO(8) , CH(3) COOK) and CaCl(2) . Our observed median lethal concentration estimates (LC50(96-h) ) for NaCl were over two times higher than values presented in previous studies, which suggests variability in tolerance among R. sylvatica populations. The deicers varied greatly in their toxicity, and further research is warranted to examine the differential effects of this suite of deicers on other species.

Do Deicing Agents Affect the Quality and Quantity of Aliphatic and Polyaromatic Hydrocarbons in Asphalt Pavements?

Chemical deicing plays a fundamental role for traffic safety on roads and runways in winter season. Traditional deicing chemicals, such as sodium chloride and urea have, however, undesirable effects on surface and ground waters. For more sustainable road and runway winter maintenance, easily biodegradable organic salts such as acetates and formates, have been proposed and taken into use. Next to environmental impacts, deicing chemicals may also affect asphalt pavements. This paper investigates whether traditional or alternative deicers change the quality or quantity of polyaromatic and aliphatic petroleum hydrocarbons in asphalt pavements. Asphalt core samples were taken from two highways and two airports in Finland and analyzed for polyaromatic and aliphatic petroleum hydrocarbons, residual deicer chemicals, and hydraulic conductivities. Results for similar pavements exposed to different deicers were compared. In addition, heat treatment experiments were conducted for the core samples. The current study shows that deicers change neither the quality nor the quantity of polyaromatic and aliphatic petroleum hydrocarbons. No changes were recorded in samples heated up to 100 oC.

Closed-loop snowplow applicator control using road condition measurements

Closed-loop control of a snowplow applicator, based on direct measurement of the road surface condition, is a valuable technology for the optimisation of winter road maintenance costs and for the protection of the environment from the negative impacts of excessive usage of de-icing chemicals. To this end, a novel friction measurement wheel is designed to provide a continuous measurement of road friction coefficient, which is, in turn, utilised to control the applicator automatically on a snowplow. It is desired that the automated snowplow applicator deploy de-icing materials right from the beginning of any slippery surface detected by the friction wheel, meaning that no portion of the slippery road surface should be left untreated behind, as the snowplow travels over it at a reasonably high speed. This paper describes the developed wheel-based measurement system, the friction estimation algorithm and the expected performance of the closed-loop applicator system. Conventional and zero velocity applicators are introduced and their hardware time delays are measured in addition to the time delay of the friction estimation algorithm. The overall performance of the closed-loop applicator control system is shown to be reliable at typical snowplowing speeds if the zero velocity applicator is used.

Corrosion effects of runway de-icing chemicals on aircraft alloys and coatings

Corrosion effects of five runway de-icing chemicals on aluminium alloy 2024, magnesium alloy RZ5 and cadmium-plated and subsequently chromate-treated steel 4340 were investigated by cyclic polarisation measurements, open circuit potential monitoring and cyclic chemical exposure tests. The runway de-icing chemicals included in the study contained urea, which has a long history as a runway de-icing chemical, and four new commercial de-icing chemicals, which were based on betaine and potassium formate. Corrosion effects of urea on aluminium alloy 2024 were more pronounced than those of the new de-icing chemicals. In urea, the breakdown potential, indicating the onset of pitting, was clearly distinguishable in the cyclic polarisation curve and pitting corrosion was detected on the specimen surface after all three types of tests. Weight losses during the chemical exposure tests were also higher for urea than for the other four chemicals, where pitting corrosion was only occasionally detected. The opposite was true in the case of magnesium alloy RZ5: although the alloy experienced general corrosion in each de-icing chemical included in the study, the rate of corrosion was often higher in the new de-icing chemicals than in urea. Corrosion effects of the five de-icing chemicals on cadmium-plated and chromate-treated high-strength steel 4340 were slightly different in all three tests, indicating that differences in coating quality, particularly in the thickness of the coating layers, might have influenced the results. Overall, however, partial loss of the coating layers occurred in all studied de-icing chemicals.

Short-term effects of alternative de-icing chemicals on tree sapling performance

The use of sodium chloride (NaCl) as a road de-icer causes environmental problems and alternatives with less environmental impact are sought. This study compares the effects of three de-icers, calcium magnesium acetate (CMA), potassium formate (KFo) and NaCl, on tree performance. Growth and stress responses of tree saplings were tested in a pot experiment with five species and three substrates at increasing de-icer concentrations in soil during vegetative growth. A negative effect of increasing soil concentrations of de-icers were found for many of the responses, but the effects varied among plant species. Root growth decreased in both of two species tested, leaf biomass decreased in four of the five species and stem diameter increase decreased in two of the five species. De-icer treatments had no effect on specific leaf area, relative chlorophyll content, height increase or chlorophyll fluorescence (Fv/Fm) responses. The negative effects of increasing de-icer concentration were independent of substrate characteristics, except for root growth in Acer platanoides and Pinus sylvestris and shoot growth in A. platanoides, where higher soil organic matter content improved plant performance under salinity. The negative effects of increasing concentrations were similar for all three de-icers when compared on a similar anion basis. Hence, the two organic de-icers, CMA and KFo, did not have less impact on tree sapling performance than NaCl during active growth.

Climate conditions and consequences for de-icing operations as exemplified by the situation on a motorway and airport at Gardermoen, Norway

Large amounts of de-icing chemicals are used in the northern hemisphere to maintain winter safety on roads and airports every year. At Gardermoen, potassium formate (KFo) is used on runways, sodium chloride (NaCl) on roads and propylene glycol (PG) for aeroplanes. The total use of de-icing chemicals is an important part of the risk assessment related to water contamination at Gardermoen. The objective of this paper is to examine how climatic factors affect the use of de-icing chemicals through interviews with de-icing operators and by statistical methods using data on climate variables and de-icing operations. A multiple linear regression model shows a good relationship between daily dew point temperature, precipitation, wind speed, number of departures and the use of PG. The results were less promising for the prediction of KFo. This might be explained by the human factor and insufficiency of the standard climate variables to represent the situation near the runway. An analysis of daily downscaled climate change scenarios for the Gardermoen area revealed insufficient detail for any accurate estimates of change in total consumption of de-icing chemicals. The predicted mean increase of 7.6°C during winter does, however, suggest a reduced need for de-icing chemicals in the long term (2071–2100).

Resistance of Portland Cement Pervious Concrete to Deicing Chemicals

The damaging impact of deicing chemicals on portland cement pervious concrete materials was investigated. Two concrete mixes (with and without latex modification) were subjected to three deicing chemicals (sodium chloride, calcium chloride, and calcium-magnesium acetate) under a freezing–thawing or drying–wetting condition. Two deicing chemical application methods (saturated and drained) were employed. The impact of deicing chemicals on the concrete was evaluated based on concrete mass and strength losses. Of the deicing chemicals studied, the calcium chloride solution caused the most damage, while the calcium magnesium acetate caused the least. The saturated scaling test method, followed according to ASTM C672, provided much higher mass loss of tested concrete samples when compared with a modified, more realistic drained test method.

Eco-friendly methods of reducing the consequences of winter maintenance in urban green areas

Abstract Trees play a crucial role in the urban environment. They fulfil aesthetic, sociocultural, ecological, health-promoting and economic functions. Urban development and related human activity bring many risks to green areas within urban space. Plants are exposed to stress connected with water, soil and air pollution. Living space, harmful light and thermal conditions, drought, high density and changeable soil pH with excessive salinity are further disadvantages. European and Northern American cities have to cope with a serious danger of tree death. A leading cause is the use of de-icing chemicals in winter, particularly sodium chloride, applied due to its cost-effectiveness and availability. The paper describes traditional de-icing chemicals used in urban areas (NaCl, solid aggregates, CaCl2, MgCl sulphates MgSO4, (NH4)2SO4, urea alcohols and glycols isopropyl alcohol, ethylene glycol, methanol) and newly developed sodium chloride substitutes (calcium magnesium acetate CMA), sodium formate and acetate NaFo/NaAc, potassium carbonate K2CO3). Moreover, prophylactic methods aimed at preventing the negative impact of de-icing campaigns, rules of planning and design of urban landscape, and reasonable management measures and pro-ecological modern technologies reducing and reversing the consequences of harmful actions are presented

Aquatic Toxicity of Airfield-Pavement Deicer Materials and Implications for Airport Runoff

Concentrations of airfield-pavement deicer materials (PDM) in a study of airport runoff often exceeded levels of concern regarding aquatic toxicity. Toxicity tests on Vibrio fischeri, Pimephales promelas, Ceriodaphnia dubia, and Pseudokirchneriella subcapitata (commonly known as Selenastrum capricornutum) were performed with potassium acetate (K-Ac) PDM, sodium formate (Na-For) PDM, and with freezing-point depressants (K-Ac and Na-For). Results indicate that toxicity in PDM is driven by the freezing-point depressants in all tests except the Vibrio fisheri test for Na-For PDM which is influenced by an additive. Acute toxicity end points for different organisms ranged from 298 to 6560 mg/L (as acetate) for K-Ac PDM and from 1780 to 4130 mg/L (as formate) for Na-For PDM. Chronic toxicity end points ranged from 19.9 to 336 mg/L (as acetate) for K-Ac PDM and from 584 to 1670 mg/L (as formate) for Na-For PDM. Sample results from outfalls at General Mitchell International Airport in Milwaukee, WI (GMIA) indicated that 40% of samples had concentrations greater thanthe aquatic-life benchmarkfor K-Ac PDM. K-Ac has replaced urea during the 1990s as the most widely used PDM at GMIA and in the United States. Results of ammonia samples from airport outfalls during periods when urea-based PDM was used at GMIA indicated that 41% of samples had concentrations exceeding the U.S. Environmental Protection Agency (USEPA) 1-h water-quality criterion. The USEPA 1-h water-quality criterion for chloride was exceeded in 68% of samples collected in the receiving stream, a result of road-salt runoff from urban influence near the airport. Results demonstrate that PDM must be considered to comprehensively evaluate the impact of chemical deicers on aquatic toxicity in water containing airport runoff.

Precision of method for determining resistance of bituminous mixtures to de-icing fluids

This paper presents the results of a Round-Robin test to estimate the precision of European method EN-12697-41 “Test methods for hot mix asphalt-Resistance to de-icing fluids”. The purpose of the project was to determine precision data according to ISO 5725, ASTM E691 and ASTM C802. The examined test method is intended for use in requirements specifications for airfield de-icing chemicals and/or as a tool for development of such products. Precision statistics, repeatability and reproducibility standard deviations, are based on observed values from six laboratories and six levels, each level comprising four samples. From a general statistical analysis, which was conducted in addition to precision determination, it could be concluded that the most damaging de-icing agents (treatments) were identified by all participating laboratories both in terms of absolute values and by ranks.