Thesis advisor: Rudolph Hon / Road salt deicers are necessary for road safety, yet pose a risk to wildlife and public water supplies by increasing major ion loads above EPA limits. To better understand the fate of deicers after application, we need to know the migration routes and subsurface pathways that deicers take from their sources to points of discharge. This project used sediment core analysis and major ion chemistry analysis of water quality to evaluate the pathways of NaCl and CaCl2 through the subsurface of a shallow glacial aquifer in south east New England. Assessment of sediment cores revealed a heterogeneous subsurface with great variation in hydraulic conductivity. Analysis of major ion concentrations and ion ratios showed both short, direct pathways and deeper, longer pathways indicative of yearly salt retention in the aquifer. Ion chemistry also revealed deicer sources by their variable NaCl to CaCl2 ratios. / Thesis (MS) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

An investigation on the damaging effects of potassium acetate deicer (KAc) on concrete durability was conducted. Different SCM replacement levels were used. ASTM C 1293 and ASTM C 1260 test methods results indicated that KAc is capable of inducing alkali-silica reaction (ASR) expansion in specimens containing reactive aggregate. Class C fly ash was ineffective even at a replacement level of 45%. Class F fly ash and slag were effective in mitigating ASR expansion for specimens exposed to diluted (25% by weight) KAc. KAc showed an increase in pH value upon exposure to concrete specimens. Concrete specimen without SCM and exposed to deicers had higher [K]/[Na] molar ratio near the surface but ions penetrated less compared to specimens containing SCM. ASTM C 666 and MTO LS-412 test methods results showed that air-entrained concrete slabs and prisms without SCM and exposed to KAc are resistant to scaling and freezing and thawing damage.

An investigation on the damaging effects of potassium acetate deicer (KAc) on concrete durability was conducted. Different SCM replacement levels were used. ASTM C 1293 and ASTM C 1260 test methods results indicated that KAc is capable of inducing alkali-silica reaction (ASR) expansion in specimens containing reactive aggregate. Class C fly ash was ineffective even at a replacement level of 45%. Class F fly ash and slag were effective in mitigating ASR expansion for specimens exposed to diluted (25% by weight) KAc. KAc showed an increase in pH value upon exposure to concrete specimens. Concrete specimen without SCM and exposed to deicers had higher [K]/[Na] molar ratio near the surface but ions penetrated less compared to specimens containing SCM. ASTM C 666 and MTO LS-412 test methods results showed that air-entrained concrete slabs and prisms without SCM and exposed to KAc are resistant to scaling and freezing and thawing damage.

Thesis advisor: Rudolph Hon / Over 10 million tons of deicers are applied on impervious surfaces during winter storms in the United States every year to create safer driving and walking conditions. Road salt, or sodium chloride, is the most common deicer due to its low price and wide availability. Increasing concentrations of sodium chloride (NaCl) over the past decades have been measured in surface waters and groundwater throughout North America and it is projected to continue increasing. As there are no cost effective alternatives available to road salt, its potential role as an environmental and drinking water contaminant needs to be investigated. Field measurements from previous studies reveal the homogenization of NaCl in the subsurface through consistent elevated levels year-round. Through the integration of field and laboratory methods, this thesis aims to investigate the role of subsurface processes in the transport and pathways of deicers from the point of deposition to eventual emergence in surface waters and its potential impact on drinking water supplies. To understand the contamination pathways of NaCl that result in the observed surface water concentrations, experimental simulations were designed that indicate that gravitational/convective processes are the most important initial processes influencing deicer transport, but that other processes such as diffusion, surface tension, and dispersion/advection also play important roles. / Thesis (MS) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Thesis advisor: Rudolph Hon / Road de-icing salts (predominantly NaCl, CaCl2, and MgCl2) are applied each winter in the northern US, northern Europe, and Canada to maintain safe driving conditions. It is widely recognized that road salt enters the environment through runoff and infiltration (Williams et al., 2000; Ostendorf, et al., 2001; J. Marsalek, 2003), resulting in salinization of freshwater (Godwin et al., 2003; Kaushal et al., 2005; Kelly et al., 2012). The chloride concentration (a proxy for deicers) has doubled in the last 20 years in the groundwater Norwell, MA, the primary public water supply for the town’s residents, and often exceeds the EPA secondary drinking water standard for chloride. The annual budget TDLCl¬ of Third Herring Brook in Norwell, MA is estimated using specific conductance and discharge datasets to determine the retention of dissolved deicers in the watershed during the study period. The estimated retention rate is between 59% and 78%. / Thesis (MS) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

No description available.

The objectives of this research were to 1) compile winter maintenance data for the Utah Department of Transportation (UDOT) to directly compare concrete and asphalt pavements with regards to deicer usage and 2) determine if there is a statistical difference in deicer usage on concrete and asphalt pavements. To this end, three data sources were consulted for this research: Material Maintenance Quality Assurance (MMQA) database, UDOT road database, and Google Maps. The final compiled data set prepared for analysis in this research contained deicer quantities by deicer type, pavement surface areas by pavement material type, traffic, longitude, latitude, and elevation data. The deicer data evaluated in this analysis represented the total quantities of each deicer distributed during the 8-year period during which the MMQA database was used by UDOT.Several multiple linear regression analyses were performed to determine if concrete or asphalt pavements required different amounts of deicers, including salt, Redmond salt, brine, wetted salt, magnesium chloride, sand, pre-mix, and wetted pre-mix, during the winter seasons evaluated in this research. Because plow routes were not equal in total pavement area, a variable called “concrete proportion” was created. Similarly, traffic and deicer quantities were divided by total pavement area in lane miles to account for the variation in maintenance station sizes and to allow for direct comparison of the various maintenance stations. After the values of the independent variables were finalized, full and reduced models were created for the total amount of all deicers per lane mile and the amounts of each of the eight individual deicers per lane mile based on the statistical significance of the respective independent variables. A total of 18 regression models were completed for this research.From the results of the statistical analyses, concrete proportion was statistically significant in models for three of the dependent variables, including brine, wetted salt, and wetted pre-mix. However, neither the full nor the reduced regression model prepared for the sum of all deicers had concrete proportion as one of the significant variables. The absence of concrete proportion as an independent variable in these models shows that, on average, after correcting for differences in traffic volume and pavement area, deicer usage in Utah is not affected by pavement type. Therefore, except in areas where applications of brine, wetted salt, and wetted pre-mix are common, winter maintenance costs should not be a factor in the determination of pavement type.

Örebro flygplats är en central knutpunkt för luftfarten inom regionen. I och med att flygplatsen har Sveriges fjärde största fraktflygplansanläggning, ställs höga krav på flygsäkerheten. Därför används det varje vinter stora mängder avisningsvätska för att hålla flygplanen fria från is och snö. Senaste säsongen användes över 74 000 kg avisningsvätska som är främst bestående av propylenglykol. Men hur effektivt är reningssystemet på flygplatsen för att minimera den förbrukade vätskans miljöpåverkan? Denna studie undersöker flygplatsens rening av förbrukad avisningsvätska i deras dagvattensystem. Främsta fokus är att undersöka markbädden som är den huvudsakliga reningsmetoden för förbrukad avisningsvätska, men även dagvattendammen som ska rena övrigt dagvatten utan avisningsvätska. Tidigare har det uppdagats att höga värden av kemisk syreförbrukning (COD mg/l) förekommer i både markbädden och dagvattendammen. Det har konstaterats att propylenglykol är lätt nedbrytbart och kräver mycket syre för att brytas ned. Denna höga syreförbrukning leder till höga COD-värden samt kan leda till syrebrist i vattnet.Studien består av provtagningar och analyser av dagvatten från olika delar av dagvattensystemet, inklusive markbädden och dagvattendammen. Samtliga prover har analyserats för COD-värden, mer ingående analyser har gjorts för metaller och pH-värden i markbädden. Analyserna visar att markbäddens förmåga att rena avisningsvätska är otillfredsställande och att det fortfarande finns höga COD-värden i utloppet av bädden. Det konstateras också att dagvattendammen tar emot avisningsvätska via oavsiktliga spridningsvägar, vilket påverkar vattenkvaliteten negativt. Förbättringsåtgärder krävs för att hantera avisningsvätska mer effektivt för att minimera dess negativa miljöpåverkan. Det rekommenderas att markbädden syresätts och att mikroorganismer tillförs. Vidare är det också viktigt med en effektiv uppehållstid för det tillkommande vattnet, för att uppnå ett kontinuerligt flöde. Dagvattendammen är i behov av en längre uppehållstid för vattnet innan det når utloppet för att minimera höga COD-värden i utgående vatten mot recipient. Dessa åtgärder bidrar till att säkerhetsställa en bättre vattenkvalité för det utgående dagvattnet till recipient. / Örebro Airport is a central hub for aviation in the region. With the airport being Sweden's fourth-largest cargo aircraft facility, high demands are placed on flight safety. Therefore, large amounts of deicing fluid are used every winter to keep the aircraft free from ice and snow. Last season, over 74,000 kg of deicing fluid, primarily consisting of propylene glycol, was used. But how effective is the airport's treatment system in minimizing the environmental impact of the used fluid?This study investigates the airport's treatment of spent deicing fluid in their stormwater system. The main focus is on examining the constructed wetland, which is the primary treatment method for used deicing fluid, but also the stormwater pond, which is supposed to treat other stormwater without deicing fluid. Previously, high values of chemical oxygen demand (COD mg/l) have been found in both the constructed wetland and the stormwater pond.It has been established that propylene glycol is readily biodegradable and requires a lot of oxygen to break down. This high oxygen demand leads to high COD values and can cause oxygen depletion in the water.The study consists of sampling and analyzing stormwater from different parts of the stormwater system, including the constructed wetland and the stormwater pond. All samples have been analyzed for COD values, with more detailed analyses conducted for metals and pH levels in the constructed wetland. The analyses show that the constructed wetland's ability to treat deicing fluid is unsatisfactory and that high COD values still exist in the outflow of the wetland. It is also noted that the stormwater pond receives deicing fluid through unintended pathways, which negatively affects water quality.Improvement measures are required to handle deicing fluid more effectively to minimize its negative environmental impact. It is recommended that the constructed wetland be aerated and that microorganisms be introduced. Furthermore, an effective retention time for the incoming water is crucial to achieve a continuous flow. The stormwater pond needs a longer retention time for the water before it reaches the outflow to minimize high COD values in the outgoing water to the recipient. These measures will help ensure better water quality for the outgoing stormwater to the recipient.

Master of Science / Department of Civil Engineering / Kyle Riding / Concrete is most widely used material in construction industry, which is made up of cement, water and aggregates as its major ingredients. Aggregates contribute to 60 to 75 % of the total volume of concrete. The aggregates play a key role in the concrete durability. The U.S Midwest has many aggregates that can show distress in the field under freezing and thawing conditions. The objective of this research was to determine if the Test Method for the Resistance of Unconfined Coarse Aggregate to Freezing and Thawing, method CSA A23.2-24A, could be used to differentiate good from poor performing aggregates in concrete. In this study fifty one KDOT aggregates (including twelve ledge and thirty nine production samples) were tested for freeze thaw resistance using CSA A23.2-24A test method and were compared to the results of the standard KDOT aggregate qualification tests. In addition to performing the CSA test method using a 3% sodium chloride solution, a subset of the aggregates were tested using either a 3% magnesium chloride or calcium chloride solution to determine the effects of the salt type on the aggregate performance. No correlation was found between the CSA A23.2-24A test method results and the standard KDOT aggregate qualification tests. The results also indicated that the mass loss in the CSA A23.2-24A was similar for the aggregate sizes tested. The use of alternate salt solutions like MgCl2 and CaCl2 resulted in increased freeze thaw mass loss in limestone aggregates.