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A novel strategy was used to assess the risk to health from exposure to polycyclic aromatic hydrocarbons (PAHs), an important class of chemical carcinogens, in workers in the paving and roofing industries using bitumen. The aim was to evaluate the risk of exposure to PAHs at three different stages: these were external exposure "external dose", internal exposure "internal dose" and biological effect "biologically effective dose". The approaches used for quantifying the risk at these stages were ambient monitoring, biological monitoring and biological effect monitoring, respectively. Ambient monitoring was carried out by personal air sampling and measurement of PAH-exposure. Excretion of thioethers (a non-selective biomarker) and 1-hydroxypyrene (a selective biomarker of exposure to pyrene) in urine were determined. Urinary d-glucaric acid, sister chromatid exchange in peripheral blood lymphocytes and micronuclei in exfoliated cells were use for biological effect monitoring. Seven groups of workers were studied. These were office workers, departmental staff and manual workers who were not occupationally exposed to PAHs and who were included as controls, and two groups of payers and roofers who were exposed to bitumen fumes during their work. The ambient monitoring program revealed that concentrations of PAHs in environmental air could be as high as those found in the payers' and roofers' occupational environments. The contribution of these background levels to the external dose of the pa yers and roofers was considerable. Payers and roofers were occupationally exposed to low levels of PAHs. The PAH profile in the personal air sample of the workers was different between the two industries. This was attributed to the presence of PAH-emission sources other than hot bitumen, such as vehicle exhaust. The concentration of naphthalene measured in air samples was a good indicator for identifying the existence of these sources. The quantitative evaluation of the carcinogenic risk inherent in the external dose using the 8 hour TWA concentration as a measuring stick did not seem to be effective due to the low "noise" levels of carcinogenic PAHs present. A semi-quantitative measure of the external exposure was suggested which appeared to be a better reflection of the carcinogenic risk. Urinary thioethers are not sensitive enough to be used as a nonselective biomarker of exposure to low levels of PAHs; however, urinary 1- hydroxypyrene was a good indicator of internal exposure to pyrene and therefore PAHs in bitumen fume. The relationship between 1-hydroxypyrene in urine and specific airborne PAH-exposure indices in the results of the payers, but not the roofers, suggested that the route of exposure in the latter is mainly dermal while that in the payers is more related to respiratory uptake. This observation, however, did not agree with the subjective occupational hygiene assessment where it was observed that the roofers were closer to the source of PAH-emissions due to the nature of their job and both groups did not use any respiratory or personal protective equipment. The measurement of urinary d-glucaric acid excretion suggested, but not strongly, that hepatic enzyme activity was induced in the occupationally PAH-exposed groups in comparison to controls and reflected the internal dose of pyrene or total PAHs. These observation; however, need further investigation. Micronuclei in exfoliated epithelial cells could not be measured in these populations as insufficient bladder epithelial cells were obtained for analysis. Sister chromatid exchange in peripheral blood lymphocytes of payers and roofers was significantly elevated in comparison to control and manual worker group. The group mean frequencies of SCE were significantly correlated with the external exposure to carcinogenic PAHs. This observation suggested that sister chromatid exchange is a very sensitive cytogenetic endpoint and is useful for evaluating the risk of exposure to low levels of carcinogenic PAHs. Risk assessment, such as the one conducted in this study, allows a quantitative estimation of risk associated with long-term exposure to moderate and low levels of airborne exposure to PAHs in bitumen fume. Knowledge of dose response relationship may allow a review of current Occupational Exposure Standards (OES) and Biological Exposure Limits, which are at present either unavailable or based on poor background scientific knowledge for most PAH compounds. In this study we have suggested an Occupational Exposure Limit for PAHs based on the sum of fourteen PAH-species.

The demand for accurate bitumen-pentane mass transfer data was the main motivation behind this research. Difficulties such as complex phase behavior, high viscosity and opacity of the hydrocarbon invariably lead to failure of conventional techniques to measure mass transfer coefficients involving heavy oils. To address this issue, X-ray transmission tomography has been employed for such measurements. The initial set of experiments in this study measured the free mutual diffusion coefficient of pentane-Athabasca/bitumen, as well as pentane-atmospheric residue. In addition, forced mass transfer between pentane and both bitumen and atmospheric residue was studied. Forced mass transfer between pentane and these two heavy oils followed a similar pattern when normalized and the pattern is consistent with prevailing understanding. However, mass transfer rates between pentane and Athabasca atmospheric residue are one order of magnitude smaller than for the corresponding bitumen case. Impacts on the effectiveness of proposed production and refining processes are discussed. / Chemical Engineering

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on April 1, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Engineering, Department of Chemical and Materials Engineering, University of Alberta. Includes bibliographical references.

As conventional oil reserves deplete and more efficient refining technologies emerge, the use and transportation of heavy fuel oils such as dilbit is rising. Despite the risk of accidental dilbit spills, the fate and behaviour in aquatic systems is largely unknown. The objective of this thesis was to develop new approaches and insights to directly address knowledge gaps surrounding the fate and behaviour of diluted bitumen (dilbit) in freshwater systems. During the summers of 2017 and 2018, a large-scale collaborative field study was conducted at the International Institute for sustainable Development’s – Experimental Lakes Area (IISD-ELA), a world-renowned freshwater research station located in Northwestern Ontario, Canada. First, two tank-based dilbit spill simulations were carried out at oil:water ratios of 1:8000 and 1:800 v/v (Chapter 2). Here I examined the physical fate and behaviour of dilbit spilled onto the water’s surface for 11 days. In this chapter I provide, for the first time, experimental evidence of dilbit physically sinking after 8 days of environmental weathering in land-based tanks containing natural lake water. Building on the findings of chapter 2, the remaining four chapters focus on a series of 70-d long experimental dilbit spills carried out in limnocorrals (10 m diameter x 1.5 m depth) installed directly in a freshwater lake. Chapter 3 provides, to our knowledge, the most detailed temporal account to date of dilbit submergence in freshwater at multiple oil:water ratios. In Chapter 4 I provide the rates at which over 100 individual hydrocarbons are depleted over time from the dilbit slicks and apply diagnostic ratios to postulate which weathering processes are responsible for the observed depletions. As predicted, evaporation, dissolution, and photooxidation are prominent weathering processes whereas biodegradation is not. I then describe both the short- and long-term behaviour of these compounds as they partition from the dilbit slick to the air, water, and sediments of the limnocorrals in Chapter 5. While the concentrations of polycyclic aromatic hydrocarbons (PAHs) were elevated in the water columns of each treatment, they were orders of magnitude lower than concentrations that pose a toxicological risk. The same was true for all sediment samples except those that were in direct contact with sunken dilbit. This suggests that the major threat of dilbit spills from an ecotoxicological point of view is the dilbit-laden sediments produced by submergence. Finally, I demonstrated the successful application of a mass transfer model to predict the dissolution trends of the highly toxic benzene, toluene, ethylbenzene, and o,m,p-xylene (BTEX) compounds following the dilbit spills. In Chapter 7 I detail the implications and conclusions for each chapter and the thesis as a whole. I also describe areas where future research is needed. In the end, the conclusions of this thesis were: 1) dilbit has the propensity to sink following spills in freshwater, 2) prominent weathering processes include evaporation, dissolution, and photooxidation, 3) our regression design allowed for important relationships between contamination and spill size to be realized, 4) sunken dilbit poses a toxicological threat to aquatic biota, and 5) mass transfer models can accurately predict BTEX dynamics in the water column following a dilbit spill.

This thesis delves into exploring lignin's potential as a sustainable substitute for bitumen within asphalt mixtures, with the overarching goal of reducing the environmental footprint of the asphalt industry. By conducting a meticulous blend of literature reviews and comprehensive laboratory experiments, the research examines the performance and ecological sustainability of lignin-infused asphalt mixtures. The primary objective is to assess lignin's efficacy as a binding agent in asphalt pavements and its potential to create more sustainable and environmentally friendly road materials. Key inquiries encompass comparative analyses of lignin-based asphalt mixtures against conventional bitumen-based counterparts, alongside an exploration of the environmental advantages and challenges associated with lignin utilization. Through laboratory assessments and analyses, including examinations of tensile strength, permanent deformation and air voids, the study evaluates the performance and sustainability of lignin-infused mixtures. Notable findings indicate significant environmental benefits, such as reduced CO2 emissions and enhanced water resistance. However, despite promising results meeting Swedish Transport Administration requirements, further optimization is essential to enhance competitiveness.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The increasing awareness of climate change causes a growing interest in pavement rehabilitation. Pavement rehabilitation by in-situ stabilisation with bitumen reduces the extraction of natural aggregate resources while enhancing flexibility and durability properties, which lowers maintenance costs over the design-life of the pavement structure. Incorporating Bitumen Stabilised Materials (BSMs) into a pavement structure can therefore have economic and environmental benefits, but more research is needed to fully understand the behaviour and potential of these materials. Stabilising materials with bitumen provides useful properties to pavement layers. The “TG2 2nd Edition, Bitumen Stabilised Materials” was published by the Academy of South Africa in May 2009, which provides a good understanding of the usage of Bitumen Stabilised Materials (BSMs). However, the shrinkage and flexible behaviour of these materials are still not fully understood and therefore more research on these materials is needed. The aim of this project is thus to determine the shrinkage and flexible behaviour of BSMs to incorporate these behavioural types in the revised design method for flexible pavements in the SAPDM. In addition, the influence of several additives on the shrinkage and flexible behaviour of BSMs have been evaluated to get an improved understanding of these properties. The additives included cement (1% and 2% content) and both bitumen emulsion (0.9% and 2.4% content) and foamed bitumen (only 2.4% content). Two linear shrinkage testing methods have been designed to test the shrinkage potential of BSMs, including a beam testing method and a cylindrical testing method. Based on the usage of the shrinkage measurements the applicable method can be used to determine the shrinkage potential of a BSM. The flexibility is a more complex property and was tested using a simple monotonic beam test. The strain-at-break parameter obtained from this test provided an indication of the material flexibility. Slight differences in the trends were observed between beam and cylindrical shrinkage due to specimen geometry, exposed surface area and shrinkage testing direction. Beam specimens initially show swelling when bitumen is added to the mixture and shrinks thereafter. Cylindrical specimens on the other hand show initial shrinkage followed by a slight length increase, where after shrinkage continues. The additives had the same influence on the shrinkage for both the beam and cylindrical specimens. Although all shrinkage measurements were small, an increase in bitumen reduced shrinkage and an increase in cement increased shrinkage. Stabilisation with foamed bitumen rather than bitumen emulsion proved to show less shrinkage, but only in combination with 2% cement. The strain-at-break, dissipated energy and material stiffness calculated from the monotonic beam tests provided a good indication of the flexibility behaviour of BSMs. Higher bitumen content increased the flexibility potential and an increase in cement decreased the flexibility potential of BSMs. This project has provided good insight on both the shrinkage and flexibility behaviour of BSMs, which can be used in the revised copy of the SAPDM. Increased bitumen contents decreases the shrinkage potential and increases the flexibility of a BSM. Increased cement contents on the other hand, increases shrinkage and decreases flexibility of BSMs. The correct combination of cement and bitumen in a BSM can thus provide a material with the wanted flexibility while keeping the shrinkage to a minimum. / AFRIKAANSE OPSOMMING: Die toenemende bewustheid van klimaatsverandering veroorsaak toenemende belangstelling in die rehabilitasie van plaveisels. Plaveisel rehabilitasie deur in-veld stabilisasie met bitumen verminder die ontginning van natuurlike hulpbronne, terwyl die verbetering van buigsaamheid en duursaamheid eienskappe die onderhoudskoste verlaag oor die ontwerp-lewe van die plaveiselstruktuur. Die inkorporasie van Bitumen Gestabiliseerde Materiale (BGM) in 'n plaveisel struktuur kan dus omgewings en ekonomiese voordele inhou. Meer navorsing word wel benodig om die gedrag van hierdie materiale beter te verstaan. Die stabilisering van materiale met bitumen verskaf nuttige eienskappe aan 'n plaveisellaag. Die "TG2 2de Uitgawe, Bitumen Gestabiliseerde Materiale" is gepubliseer deur die Akademie van Suid-Afrika in Mei 2009 en verskaf 'n goeie begrip van Bitumen Gestabiliseerde Materiale (BGM). Die krimpings en buigsaamheid gedrag van die materiaal word wel nog nie ten volle verstaan nie en daarom word meer navorsing oor hierdie materiaal benodig. Die doel van hierdie projek is dus om die krimpings gedrag sowel as die buigsaamheid gedrag van 'n BGM te bepaal en sodoende die kennis te gebruik in die hersiende ontwerp metode vir buigsame plaveisels in die SAPDM. Die invloed van verskeie bymiddels op die krimpings en buigsaamheid gedrag van 'n BGM is ook geëvalueer om 'n beter begrip van hierdie eienskappe te verkry. Die bymiddels sluit sement in (1% en 2% inhoud) asook beide emulsie bitumen (0,9% en 2,4% inhoud) en skuim bitumen (slegs 2.4% inhoud). Twee lineêre krimpings toets metodes was ontwerp om die krimping potensiaal van BGM's te bepaal, wat 'n balk toets metode en 'n silindriese toets metode insluit. Die metode wat gebruik sal word om die krimping van 'n BGM te bepaal moet baseer word op die toepassing waarvoor die krimpings resultate gebruik gaan word. Die buigsaamheid is 'n meer komplekse eienskap en was getoets met behulp van 'n eenvoudige monotoniese balk toets. Die spanning-by-breekpunt waardes wat verkry was vanuit die balktoetse, het 'n goeie aanduiding van die buigsaamheid van die materiaal verskaf. Klein verskille in krimpingstendense tussen balk en silindriese proefstukke is opgemerk tydens die projek en is veroorsaak deur die geometrie van die proefstuk, die blotgestelde oppervlakte asook die rigting van kimp toetsing. Balk proefstukke toon aanvanklike swelling wanneer bitumen bygevoeg is, gevolg deur krimping. Silindriese proefstukke aan die ander kant toon aanvanklike krimping gevolg deur 'n effense toename in lengte, waarna krimping weer plaasvind. Die bymiddles het dieselfde invloed op die krimping van beide die balk en silindriese proefstukke. Alhoewel al die krimpingswaardes baie klein was, het 'n toename in bitumen 'n vermindering in krimping voortgebring en 'n toename in sement het 'n toename in krimping voortgebring. Stabilisasie met skuim bitumen in plaas van emulsie bitumen toon verlaagde krimping, maar slegs in kombinasie met 2% sement. Die spanning-by-breekpunt, verkose energie en materiaal styfheid wat bereken is vanaf die monotoniese balk toets resultate, het 'n goeie aanduiding van die buigsaamheid gedrag van BGM's verskaf. 'n Hoër bitumen inhoud verhoog die buigsaamheid potensiaal van BGM‟s terwyl 'n toename in sement die buigsaamheid potensiaal van BGM's verlaag. Hierdie projek bied goeie insigte vir beide die krimpings en buigsaamheid gedrag van BGM's, wat in die hersiende ontwerp metode van die SAPDM gebruik kan word. Verhoogde bitumen inhoud verminder die krimping potensiaal en verhoog die buigsaamheid van 'n BGM. Verhoogde sement inhoud aan die ander kant, verhoog krimping en verminder buigsaamheid van BGM's. Die korrekte kombinasie van sement en bitumen in 'n BGM kan dus 'n materiaal produseer met die gewenste buigsaamheidseienskappe en terselfde tyd die krimping tot 'n minimum beperk.

Baigiamojo magistro darbo tikslas – ištirti Lietuvos automobilių keliams naudojamų bitumų savybes ir bitumo kiekio įtaką asfalto kokybės rodikliams. Naudojantis eksperimentinių dangų konstrukcijų bandomojo ruožo tyrimų duomenimis, atlikta viršutiniojo asfalto sluoksnio kokybės rodiklių analizė. Atlikus šių duomenų analizę, nustatytas bitumo kiekio ir mišinio fizikinių – mechaninių rodiklių tarpusavio koreliacinis ryšys. Pagal VĮ „Problematikos“ laboratorijoje atliktus bitumų tyrimų duomenis, nustatyta bitumo savybių rodiklių sietis. Tyrimų medžiaga apdorota statistiniu paketu „Statistica“. Pateiktos sunormintos bitumo kiekio ir fizikinių – mechaninių rodiklių vertės, atliktas bitumų kokybės rodiklių vertinimas. Pateiktos išvados ir rekomendacijos. / The main aim of this Master work is to analyse quality parameters of asphalt pavement and quality indicators of bitumen use for Lithuanian Roads. Using the results of the research on experimental pavement structures the quality parameters of the top layer of asphalt was analyzed. The analysis of the data allowed the correlation between the bitumen content and asphalt mixture physical and mechanical indices to be determined. Using the results of the research on „Problematika“ laboratory allowed the correlation between bitumen properties parameters. The research material was processed by means of the statistical software package „Statistica“. Standartized bitumen content and asphalt mixture physical and mechanical indices, bitumen quality indicators were valued. The conclusions and recommendations are provided.

<p>QC 20140902</p>

Det är viktigt att vägarna håller så länge som möjligt. En faktor som har en påverkan i asfaltens långvarighet är bitumen. När bitumenet föråldras försämras dess egenskaper som ökar risken att skador uppstår på asfalten. Med hjälp av olika tillsatser kan bitumenets egenskaper förbättras. En av dessa egenskaper är bitumenåldring. Sammanlagt finns det tre olika skeden i bitumenåldring. Av dessa tre skeden kommer tillverknings- och användningsskedet att undersökas. I detta examensarbete kommer tre olika tillsatsers påverkan i bitumenföråldring att undersökas. Detta kommer utföras genom laborationer där olika metoder som penetration, mjukpunkt, fraass brytpunkt, DSR, Iatroscan, GPC och FTIR kommer användas. Det kommer också utföras styvhetestester på de tillverkade asfaltskropparna. Resultaten som tas fram i detta examensarbete tyder på att Rediseten har bäst värden avseende åldring utav bitumen. Men detta tros inte vara på grund av tillsatsens inverkan i bitumen utan möjligheten att sänka temperaturen vid tillverkningen av asfalten. / It is important that roads last as long as possible. One factor that has a prolonged effect on asphalt is bitumen. When bitumen ages the characteristics deteriorates which increases the risk for damages on the asphalt. With the help of different additives the characteristics of bitumen could improve. One of these characteristics is bitumen aging. There are three different stages in bitumen aging. Of these three stages will the production and user stage be examined. In this thesis will three additives effect on bitumen aging be examined. This will be performed by doing laboratory experiments where different methods will be used such as penetration, softening point, fraass breaking point, DSR, latroscan, GPC and FTIR. Stiffness tests will be made on the constructed asphalt bodies. Results in this thesis interprets that Rediset has the best values when it comes to aging of bitumen. It is not believed to be the additives effect in the bitumen but the fact that the additive gives the opportunity to lower the temperature during the production of the asphalt.