Master of Science / Department of Civil Engineering / Kyle Riding / Some limestone coarse aggregate in concrete pavement can break down under repeated freeze-thaw cycles. Application of rock salt may increase the severity of exposure conditions because of trace compounds, such as calcium sulfate, in rock salt. Subsequently, limestone aggregate in concrete was subjected to freeze-thaw cycling in two methods: salt-treating the aggregate before batching concrete, and half-immersing concrete specimens in rock salt solution during freeze-thaw cycling. Concrete and saw-cut limestone specimens were also subjected to wet-dry cycles in varying salt solutions to examine the influence of trace compounds in rock salt. Freeze-thaw test results indicate that the test methods used were not severe enough to determine if a limestone aggregate was durable or not. The wet-dry testing was also not severe enough to determine the effects of trace compounds in salt solution.

A road in operation along with its traffic can pose aserious pollutant threat to groundwater and surface water inits vicinity. Examples of pollutants are metals from thecorrosion of vehicles, rails and poles and the wear of roadsurfaces and tyres; hydrocarbons from the wear of roadsurfaces, tyres, exhausts, oils; sodium chloride from roadsalt; and hazardous goods discharged in accidents. Eventuallypollutants that are not degraded or retarded in soil will reachgroundwater and surface water. The chloride ion in deicing saltis a good tracer. It is conservative and highly soluble and notsubject to retardation or degradation. If the chlorideconcentration has increased in groundwater or surface water inthe vicinity of a deiced road, other road-related pollutantsmight also be present in the water. Increased chloride concentrations have been observed inseveral water supplies, in groundwater as well as in surfacewater, since the 1970s. The number of affected water supplieshas also increased. The increase in chloride concentration inwaters is concurrent with the increase in deicing saltapplication and it is clear that most of the increase is due tothe application of deicing salt. The thesis presents a simple tool that quantified theincrease in chloride concentration for water in a catchmentarea, based on a steady-state water balance. The data wereefficiently processed and presented as maps with GIS. At aregional catchment area scale, substantially increased chlorideconcentrations were calculated. The variation between catchmentareas was verified by a national monitoring programme of lakes.Deicing salt application was estimated to account for more thanhalf of the total chloride load for a catchment area in the midsouth of Sweden. A distributed dynamic method was used to evaluate thetemporal and spatial variation of the chloride concentration inan aquifer. The distributed dynamic approach integrated thespreading of deicing salt from the road with the infiltrationin the unsaturated zone in the soil, which in turn wasintegrated with the groundwater flow. The simulation was runfor a 40-year period and showed a potential to describe aspecific system. <b>Keywords:</b>road, deicing salt, monitoring, chloride,catchment area, river basin, simulation, GIS, groundwater,surface water

<p>A road in operation along with its traffic can pose aserious pollutant threat to groundwater and surface water inits vicinity. Examples of pollutants are metals from thecorrosion of vehicles, rails and poles and the wear of roadsurfaces and tyres; hydrocarbons from the wear of roadsurfaces, tyres, exhausts, oils; sodium chloride from roadsalt; and hazardous goods discharged in accidents. Eventuallypollutants that are not degraded or retarded in soil will reachgroundwater and surface water. The chloride ion in deicing saltis a good tracer. It is conservative and highly soluble and notsubject to retardation or degradation. If the chlorideconcentration has increased in groundwater or surface water inthe vicinity of a deiced road, other road-related pollutantsmight also be present in the water.</p><p>Increased chloride concentrations have been observed inseveral water supplies, in groundwater as well as in surfacewater, since the 1970s. The number of affected water supplieshas also increased. The increase in chloride concentration inwaters is concurrent with the increase in deicing saltapplication and it is clear that most of the increase is due tothe application of deicing salt.</p><p>The thesis presents a simple tool that quantified theincrease in chloride concentration for water in a catchmentarea, based on a steady-state water balance. The data wereefficiently processed and presented as maps with GIS. At aregional catchment area scale, substantially increased chlorideconcentrations were calculated. The variation between catchmentareas was verified by a national monitoring programme of lakes.Deicing salt application was estimated to account for more thanhalf of the total chloride load for a catchment area in the midsouth of Sweden.</p><p>A distributed dynamic method was used to evaluate thetemporal and spatial variation of the chloride concentration inan aquifer. The distributed dynamic approach integrated thespreading of deicing salt from the road with the infiltrationin the unsaturated zone in the soil, which in turn wasintegrated with the groundwater flow. The simulation was runfor a 40-year period and showed a potential to describe aspecific system.</p><p><b>Keywords:</b>road, deicing salt, monitoring, chloride,catchment area, river basin, simulation, GIS, groundwater,surface water</p>

No description available.

En période hivernale, des fondants routiers sont épandus sur les chaussées afin de préserver la sécurité des usagers. Sous l'influence de divers paramètres, ces produits se retrouvent en partie dans l'environnement, le reste étant collecté par des systèmes de rétention des eaux de ruissellement routières. Or, les bassins de rétention ne sont pas conçus pour traiter ces fondants, et jouent uniquement un rôle de régulation des flux rejetés dans l’environnement. L’effet du NaCl sur l’environnement est néfaste, en raison de sa toxicité directe envers certains organismes et, indirectement parce qu’il contribue à augmenter la mobilité des ETM (Éléments Traces Métalliques), eux-mêmes toxiques. Ceci démontre un besoin d'assainissement particulier pour ces produits. L'objectif de cette thèse est d'étudier les transferts de NaCl par un bassin de rétention, mais également d'investiguer la possibilité d'utiliser la phytoremédiation comme base d'une solution d'assainissement des eaux de ruissellement routières. Le bassin de rétention choisi comme modèle est un bassin récent situé à Chenevières (Lorraine, France), en bordure d’une route nationale. La première partie du travail a porté sur la mesure et la caractérisation des transferts de NaCl dans ce bassin. L’eau a été collectée en entrée/sortie chaque semaine pendant 3 ans, et les concentrations en NaCl et ETM mesurées. Les conditions météorologiques et les données d’épandage de sel ont été suivies pour évaluer la proportion de sel effectivement transférée vers le réseau de collecte des eaux de ruissellement routières. Les résultats montrent que 25 à 50 % du sel épandu est effectivement collecté. De plus, les résultats sur la dynamique du NaCl prouvent que le bassin joue uniquement un rôle de rétention temporaire et de dilution avant rejet vers l’environnement. Ensuite, des mesures et analyses des sédiments du bassin et des sols de bord de route ont été conduites pour caractériser la spéciation et la mobilité des ETM dans ce contexte routier particulier. Dans ce cas précis, le NaCl n’a pas eu d’effet significatif sur la mobilisation des ETM, hormis le zinc (Zn). En revanche, il a provoqué la mobilisation d’autres ions majeurs. Concernant le traitement, les procédés conventionnels de dessalement d’eau sont trop coûteux et inadaptés. C’est pourquoi les potentialités d’une solution d’assainissement par phytoremédiation ont été explorées. Trois plantes halophytes ont été sélectionnées selon des critères permettant leur utilisation en contexte routier, Armeria maritima, Atriplex halimus et Atriplex hortensis L. Des expériences de germination/croissance ont été effectuées dans différentes conditions de salinité et de concentration en Zn pour évaluer leur tolérance à la salinité, à la présence de Zn et leurs capacités d’accumulation. Ces plantes ont montré une tolérance au NaCl dans des conditions de salinité représentatives de celles mesurées dans les réseaux d’assainissement routiers à Chenevières. De plus, les trois espèces accumulent dans leurs parties aériennes des quantités significatives de NaCl, ainsi que du zinc. L'utilisation des halophytes pour la phytodésalinisation en domaine routier s'avère être une technologie prometteuse pour répondre à la problématique de l'impact environnemental des fondants routiers. / During winter, deicing salts are spread on roads in order to preserve road safety for users. Under the influence of different parameters, these compounds are partly transferred to the environment, the rest of it being collected by the road runoff retention systems. However, road runoff retention ponds have not been designed for deicing salt treatment; they only play a role in the regulation of fluxes before their rejection into the environment. Furthermore, NaCl has a harmful impact on the environment, because of its toxicity to certain aquatic organisms and because it contributes to the increase of trace metal (TM) mobility, which are toxic as well. This shows the need for a specific treatment for these compounds. The objective of this research is to bring better understanding of deicing salt dynamics in a retention pond, but also to investigate the potential use of phytoremediation as a treatment solution for road runoff. A model retention pond was selected; it is located along a highway in Chenevières (Lorraine region, France). The first part of the work focused on the monitoring and the characterization of NaCl transfers in this pond. Water was weekly sampled for 3 years at the pond input and output and NaCl and TM concentrations were measured. Meteorological conditions and salt spreading data were monitored to appraise the salt fraction actually collected by the pond. Results showed that only 25 to 50 % of the spread salt is effectively collected. Moreover, results on NaCl dynamics proved that the pond only plays a role on transient storage and salt dilution before rejection into the environment. Moreover, measurements and analyses of sampled basin sediments and roadside soils were performed to assess speciation and TM mobility in this particular context. In this case, no significant effect of NaCl was recorded except for zinc (Zn); but major ions were mobilized. When it comes to treatments, conventional desalination technologies are too expensive and inappropriate in this context. Then, potentialities of phytodesalination were explored. Three halophyte plants were selected on the basis of specific criteria, allowing their use in road runoff context: Armeria maritima, Atriplex halimus and Atriplex hortensis L. Germination and growth experiments were run in various salinity conditions and in the presence/absence of Zn, in order to assess their tolerance to salt and Zn, as well as their accumulation abilities. These plants showed a high tolerance for NaCl in salinities in the range of those encountered in road runoff existing treatment systems at Chenevières. The three species accumulated significant amounts of NaCl and zinc in their aerial parts. The use of halophytes for phytodesalination of road runoff is a promising technique to address the issue of environmental impact of deicing salts.