När priset på naturtillgångar ökar samt att industrier måste ställa om till en mer hållbar verksamhet innebär detta även en omställning för asfaltsindustrin. Ett sätt för att använda mer återvunnet material i asfaltsindustri är att använda bindemedlet från gammal asfaltsmassa (eng.: reclaimed asphalt pavement, RAP). Detta kan dock inte göras utan komplikationer och därför måste bindemedlet föryngras innan för att kompensera för faktorer så som hög styvhet, låg krakning och trötthetsförmåga samt dålig anti-åldring förmåga hos RAPen. I det här projektet har två olika typer av föryngringsmedel använts; ett växtoljebaserat och ett petroleumbaserat mjukbitumen. Detta för att se om det var möjligt att använda förnybart och återvunnet material i bindemedlet men fortfarande uppnå samma prestanda som konventionellt bindemedel. Två blandningar gjordes hjälp av de två olika föryngringsmedlen och RAPen och analyserades parallellt med ett referensmaterial. Analyserna delades upp i två kategorier: reologi och kemi. Analyserna som föll under reologikategorin var mjukpunkt- och penetrationsanalyser, samt analyser med en dynamisk skjuvning reometer (eng.: dynamic shear rheometer, DSR) och en böjbalksreometer (eng.: bending beam rheometer, BBR). Under kemikategorin fanns analysmetoderna tunnskiktskromatografi med flamjoniseringsdetektor (TLC-FID) och Fourier transform infraröd spektroskopi (FTIR). Resultaten påvisar att åldring påverkas mycket av vilket föryngringsmedel som används, vilket blev tydligt när den reologiska förmågan testades. De kemiska analyserna gav stort sett liknade resultat oberoende av bindemedel. Blandningen som innehöll RAP och mjukbitumen visade sig vara mer mottagligt för åldring jämfört med den andra blandningen som innehöll växtolja, trots att den blandningen innehåller längre halt av RAPen. Vidare visar resultaten att blandningar kan prestera likt referensmaterialet när det kommer till reologi. Från den kemiska aspekten, uppvisar alla bindemedelsmaterial liknande egenskaper. Därför kan slutsatsen att RAPen var återvunnen med framgång när växtolja och mjukbitumen användes. / In recent years there has been a lot of focus on reduction of carbon footprint and sustainable development. For the asphalt industries, a way of doing this is to use reclaimed asphalt pavement (RAP) binders. This cannot be done without any complications and therefore, the RAP binder is normally rejuvenated to compensate for its high stiffness, and other poor properties like susceptibility to low temperature cracking and fatigue damage. In this project, two different ways of using RAP binder are investigated: one vegetable oil-based rejuvenator and one soft bitumen. Using the rejuvenator and soft bitumen together with a RAP binder, two different blends were made and compared to a reference bitumen which is commonly used in Sweden. The blends were made in such a way that the penetration values were close to the reference sample. Aging tests were performed by RTFOT and PAV. The testing of the non-aged and aged binder materials was divided into two sections: rheology and chemistry. The rheology testing included softening point, needle penetration, analysis with dynamic shear rheometer (DSR) and bending beam rheometer (BBR) whereas the chemistry testing included thin layer chromatography with flame ionization detector (TLC-FID) and Fourier transform infrared spectroscopy (FTIR). The results indicated that the ageing resistance of the binder materials is affected by the type of rejuvenator used which especially affects the rheological performance. The chemical performance was almost the same in each blend. The blend containing RAP binder and soft bitumen was more susceptible to ageing compared to the other blend containing oil-based rejuvenator even though the blend contained less of the RAP binder. The results also shows that the blends can perform equal to the reference sample for a rheological point of view. From a chemical point of view, the binders, including the reference, have the same properties. Therefore, the RAP binder was successfully recycled using both a bio-oil rejuvenator and soft bitumen.

No description available.

No description available.

This study focused on the material characterization of granular materials containing different percentages of “RAP”. A series of laboratory tests results were carried out to determine the physical and mechanical properties of natural aggregates and various aggregate-RAP blends. The results were used to evaluate methods to develop high-performance granular layer for pavement construction through proper compaction and control of RAP usage. The resilient modulus and accumulative deformation characteristics were determined in relation to RAP content, relative density, compaction method, stress level, stress state and the number of load applications. The effects of RAP content and density on the CBR values of aggregate-RAP blends under various conditions were also investigated. In addition, the effect of small strain cyclic loading on shear strength of aggregate-RAP blends was observed in laboratory tests. Results from this investigation demonstrated that: 1) adding RAP to natural aggregates may increase the resilient modulus of natural aggregates, and optimum content can be found to achieve the highest resilient modulus; 2) resilient modulus generally increases with density; higher density of aggregate-RAP blends can be achieved by using methods combining vibration and static loading. 3) deviatoric stress has more pronounced influence on accumulative deformation than confining pressure. 4) proper compaction method can reduce accumulative deformation of samples. 5) addition of RAP into aggregates results in little change in accumulative deformation when the RAP content is less than a threshold. 6) CBR value decreases with increasing RAP content and decreasing compaction effort or compacted dry density. 7) shear strength of an aggregate-RAP blend tends to increase after small strain cyclic loading. / Thesis / Master of Applied Science (MASc)

This thesis broadly addresses the issue of materials sustainability in the production of Portland cement concrete. Two methods are presented, both aimed at achieving more sustainable concrete through the use of waste and recycled materials. The first method involves utilizing reclaimed asphalt pavement (RAP) as an aggregate in structural concrete, and the second method involves utilizing waste quarry fines as partial replacement of Portland cement in concrete mixes. Many efforts have been made in recent years to justify the use of RAP aggregates in concrete. All previous efforts appear to unanimously report a reduction in concrete performance with varying proportions of RAP usage. The poor performance of RAP aggregates in concrete is attributed mainly to a larger, more porous interfacial transition zone (ITZ) and to the cohesive failure of the asphalt. It is hypothesized that the detrimental impact on the ITZ is attributable to organic compounds leached from the asphalt in the high pH pore solution. This study proves the presence of organic compounds in the pore solution and demonstrates that there is an apparent retardation of cement hydration. This study also attempted to pretreat the RAP in a sodium hydroxide (NaOH) solution to pre-leach the organic compounds. The pretreatment demonstrated that organic compounds were leached and that NaOH modified the asphalt surface chemistry. However, only a marginal improvement in compressive strength was observed by completing the pretreatment. Replacement of Portland cement by filler products is a practice aimed at reducing the carbon footprint of concrete, such as is common with Type IL Portland limestone cement. This study investigates the impact of replacing cement with seven different quarry fines materials. The quarry fines were used to replace cement at 5% to 20% by volume in either cement paste or mortar samples that were then analyzed for various physicochemical properties. It was found that all the quarry fines had detrimental impact on the hydration kinetics of cement pastes. The inclusion of quarry fines was also found to cause varying degrees of reduction in mortar compressive strength. While further analyses of the quarry fines are required, quarry fines 2, 5 and 7 did display encouraging signs to suggest the potential for use as a filler material in blended cements. / Master of Science / This thesis broadly addresses the issue of sustainability in the cement and concrete industry. Sustainability is a significant problem for the cement and concrete industry due to the large amount of carbon emissions produced in the manufacturing process of Portland cement. One method to reduce the carbon footprint of concrete is to use recycled aggregates, and reclaimed asphalt pavement (RAP) is investigated in this thesis as a recycled aggregate option. Previous studies have shown that the use of RAP in concrete results in poor mechanical performance when compared to conventional concrete. In this thesis, the RAP was pretreated by soaking it in sodium hydroxide (NaOH) to see if any improvement is noted. It was determined that the pretreatment resulted in marginal improvements in concrete performance. Another method to reduce the carbon footprint of concrete is through the use of substitutions of Portland cement. In this thesis, quarry fines from around Virginia were investigated for potential as substitutive material. Quarry fines are a by-product from quarrying operations and are often considered a waste material because they have limited applications. This study analyzed the performance of cementitious materials prepared with various substitutive percentages of quarry fines and found that, in general, the inclusion of quarry fines resulted in a decrease of mechanical performance. In total, seven quarry fines were tested and only two showed potential for use as a substitution in Portland cement concrete. These two investigations are essential in reaching the goal of reducing the carbon footprint of the cement and concrete industry.

Full-depth reclamation (FDR) in conjunction with cement stabilization is an established practice for rehabilitating deteriorating asphalt roads. Conventionally, FDR uses dry cement powder applied with a pneumatic spreader, creating undesirable fugitive cement dust. The cement dust poses a nuisance and, when inhaled, a health threat. Consequently, FDR in conjunction with conventional cement stabilization cannot generally be used in urban areas. To solve the problem of fugitive cement dust, the use of cement slurry, prepared by combining cement powder and water, has been proposed to allow cement stabilization to be utilized in urban areas. However, using cement slurry introduces several factors not associated with using dry cement that may affect road base strength, dry density (DD), and moisture content (MC). The objectives of this research were to 1) identify construction-related factors that influence the strength of road base treated with cement slurry in conjunction with FDR and quantify the effects of these factors and 2) compare the strength of road base treated with cement slurry with that of road base treated with dry cement. To achieve the research objectives, road base taken from an FDR project was subjected to extensive full-factorial laboratory testing. The 7-day unconfined compressive strength (UCS), DD, and MC were measured as dependent variables, while independent variables included cement content; slurry water batching temperature; cement slurry aging temperature; cement slurry aging time; presence of a set-retarding, water-reducing admixture; and aggregate-slurry mixing time. This research suggests that, when road base is stabilized with cement slurry in conjunction with FDR, the slurry water batching temperature; haul time; environmental temperature; and presence of a set-retarding, water-reducing admixture will not significantly affect the strength of CTB, provided that those factors fall within the limits explored in this research and are applied to a road base with similar properties. Cement content and cement-aggregate mixing time are positively correlated with the strength of CTB regardless of cement form. Additionally, using cement slurry will result in slightly lower strength values than using dry cement.

Master of Science / Department of Civil Engineering / Mustaque Hossain / The ultra-thin bonded bituminous surface (UBBS), popularly known as Novachip, is a thin hot-mix asphalt layer with high-quality, gap-graded aggregates bonded to the existing surface with a polymer-modified emulsion membrane. This thin surfacing improves ride quality, reduces road-tire noise, minimizes back spray, and increases visibility under wet conditions. The Kansas Department of Transportation (KDOT) has been using UBBS since 2002. Performance of this thin surface treatment strategy has been good in Kansas and elsewhere. However, some of these projects are now being rehabilitated. The objective of this study is to evaluate whether reclaimed asphalt pavement (RAP) materials from existing UBBS layers can be used in chip seal and Superpave mixtures. UBBS millings were studied with two different polymer-modified emulsions to assess their performance as precoated aggregates in chip seal. The ASTM D7000-04 sweep test was used to assess chip retention of UBBS millings. Three different mix designs were developed for both 12.5-mm and 9.5-mm nominal maximum aggregate size (NMAS)Superpave mixtures using a PG 70-22 asphalt binder and three different percentages (0%, 10%, and 20%) of reclaimed UBBS materials. The designed Superpave mixes were then tested for performance in terms of rutting and stripping using the Hamburg wheel tracking device (HWTD)and moisture sensitivity by modified Lottman tests. Sweep test results showed that UBBS millings did not improve chip retention. Superpave mix design data indicated volumetric properties of Superpave mixes with UBBS millings met all requirements specified by KDOT. HWTD and modified Lottman test results indicated all designed mixes performed better with the addition of UBBS millings as RAP materials. Field performance of UBBS projects was also evaluated. It was found that pavements treated with UBBS showed high variability in service life with majority serving six years. Before and after (BAA) studies showed that UBBS reduces pavement roughness, transverse and fatigue cracking one year after the treatment. However, no consistent improvement in rutting condition was found.

A restauração de pavimentos flexíveis ocasiona, em todo o mundo, problemas ambientais em função do descarte dos materiais provenientes da demolição do pavimento existente, um dos motivos pelo qual a reciclagem de pavimentos tem se mostrado, cada vez mais, uma técnica sustentável e necessária, tanto na manutenção quanto na construção de novas estruturas. Na atualidade, existem as mais diversas técnicas de reciclagem. Neste trabalho, avaliou-se a reciclagem do revestimento asfáltico fresado (RAP) com a adição de agente de reciclagem emulsionado (ARE), estudando a viabilidade de seu emprego em bases asfálticas de pavimentos novos. Por meio de um programa laboratorial de ensaios, foi realizada a análise da estocagem, cura e compactação de uma mistura produzida em uma usina de reciclagem a frio. Para tanto, utilizou-se os parâmetros de módulo de resiliência (MR), resistência à tração por compressão diametral (RTCD) e dano por umidade induzida (DUI). A compactação da mistura no laboratório foi realizada com o Compactador Giratório SUPERPAVE (CGS) e com o Compactador Marshall, sendo avaliada a influência do tempo de estocagem, que é o tempo transcorrido entre a mistura e a compactação (na condição solta), e o tempo de cura após a compactação dos corpos de prova. Os resultados indicam que os parâmetros de MR, RTCD e DUI aumentaram quando a mistura solta permaneceu estocados, pela provável interação entre o agente de reciclagem emulsionado e o ligante asfáltico oxidado do RAP. Foi observado ainda um ganho substancial nos valores de MR e RTCD durante o período de cura, o qual foi pouco influenciado pela estocagem prévia do material. Quanto ao efeito do tipo de compactação, foi possível observar que os corpos de prova produzidos no CGS apresentaram maiores valores de RTCD, MR e DUI em relação aos corpos de prova do compactador Marshall, chegando, inclusive, a dobrar o valor de RTCD após 56 dias de cura. Também foi realizada a construção de dois trechos experimentais com a mistura reciclada estudada, visando o acompanhamento da execução, assim como, o monitoramento do desempenho da mistura, em campo, ao longo do tempo. Constatou-se que foi possível atingir a densidade obtida na compactação Marshall desde que sejam utilizados rolos compactadores adequados e que a espessura da camada seja limitada em até 8 cm. Já os levantamentos deflectométricos realizados durante o monitoramento confirmaram o comportamento mecânico observado em laboratório, indicando o ganho de rigidez da base reciclada ao longo do tempo. Conclui-se, portanto, que o emprego da mistura a frio de RAP com agente de reciclagem emulsionado é uma alternativa viável para a construção de bases de pavimentos rodoviários novos. / Asphalt pavements maintenance produces worldwide residues from milling of deteriorated pavements. Therefore, pavement recycling is a sustainable and necessary technique for new pavement construction and rehabilitation. Nowadays, there many technologies to apply recycling to pavement maintenance. This study evaluated the reuse of the reclaimed asphalt pavement (RAP) mixed with emulsified asphalt recycling agent and its viability to be used as an asphalt base course in new pavements. A laboratory program was used to assess the storage, the cure and compaction of a mix of RAP - emulsified asphalt recycling agent produced in a cold central plant recycling plant (CCPR). The resilient modulus (MR), the indirect tensile strength (ITS) and the moisture induced damage (MID), were used. The compaction at the laboratory was performed using de Superpave Gyratory Compactor (SGC) and the Marshall compactor. The storage period is referred as the time elapsed between the mix and the compaction, in the loose condition. On the other hand, the curing period is associated to the period elapsed after compaction of the specimens. Results showed that the storage period has little effect on the MR, ITS and MID parameters. However, this period was important to likely allow the emulsified asphalt recycling agent to interact with the aged asphalt binder from the RAP. It was observed a substantial increase of MR and ITS parameters during the curing and, again, the storage period had little effect on this. Regarding the compaction method, the SGS specimens had higher values at ITS, MR and MID values, when compared to the Marshall specimens. At the curing time of 56 days, the ITS was doubled at the SGS specimens. Additionally, this study performed the construction of two trial sections with the studied mix. The goal was to register the execution and assess its performance in field during a period. It was verified that in field is possible to reach Marshall densities, since adequate roller compactors are used with specific thickness. The performance of the trial sections was done from FWD testing. These results confirmed the laboratory mechanical behavior of the recycled cold mix, showing that the curing increase of the stiffness. Therefore, it is concluded that the cold mix using emulsified asphalt recycling agent is a viable alternative for the base course construction of new road pavements.

A caracterização do tráfego rodoviário é de grande importância para o dimensionamento de pavimentos, bem como para a garantia de sua vida útil, sendo a carga aplicada pelo tráfego uma das maiores responsáveis pelos danos na estrutura. Com o objetivo de garantir a durabilidade dos pavimentos, sistemas Weigh-in-Motion (WIM) podem ser utilizados para coleta de informações sobre os veículos que trafegam em uma rodovia. Propôs-se neste estudo caracterizar o tráfego a partir da avaliação contínua das solicitações de carga na BR-381, sentido Sul, por meio da coleta de dados de Sistema WIM. A partir da análise dos dados coletados entre setembro de 2015 e fevereiro de 2017, observou-se que aproximadamente 85% dos veículos comerciais trafegam na faixa de rolamento mais solicitada (faixa 2). Com relação ao volume de veículos comerciais, pôde-se constatar a presença de uma maior quantidade de veículos durante os dias úteis quando comparados aos finais de semana. Além das variações com relação ao dia da semana, o volume de tráfego também apresenta particularidades com relação às distribuições horárias. Foram obtidas e analisadas as distribuições de carga para cada tipo de eixo das 15 categorias de veículos comerciais mais frequentes (representando 97,3% do tráfego comercial registrado). Com base na Legislação Brasileira vigente, quantificou-se o excesso de carga praticado na rodovia, onde foram identificados 23,7% dos veículos com excesso. Notou-se que a maioria dos excessos se encontram na faixa de até 10% dos respetivos limites legais, indicando que muitos transportadores carregam seus veículos considerando a tolerância como um ganho real de sobrecarga. Um método para identificação de padrões de viagem dos veículos com excesso foi proposto, que se baseia nas árvores de classificação e regressão (Classification and Regression Tree Analysis - CART), uma ferramenta analítica. Por fim, os dados de tráfego foram correlacionados com os defeitos observados no trecho experimental construído logo após o sistema WIM, onde se simulou a redução da vida útil de estruturas de pavimentos considerando diferentes cenários de carga, sendo eles: (i) tráfego real; (ii) tráfego na tolerância (considerando a tolerância de 10%); e (iii) tráfego legal, concluindo-se que a prática do excesso de carga nas rodovias penaliza o transporte rodoviário ao acelerar a degradação das rodovias. / The traffic characterization is of great importance for pavement design, as well as for prediction of its remaining service life. In fact, traffic loading is one of the major contributors for the pavement deterioration. In order to ensure pavement durability, Weigh-in-Motion (WIM) systems can be used to collect traffic data. Therefore, this study was conducted to analyze the effect on the pavements of characterizing the traffic through a Weigh-in-Motion system installed between km 948 and 949 at the Brazilian Federal Highway BR-381. The analysis of the data collected from September 2015 to February 2017 shows that approximately 85% of commercial vehicles travel on the outside slow lane (lane 2). Regarding the volume of commercial vehicles, traffic volume was lower in weekends. In addition to the daily variations, traffic patterns also presented hourly variations. The axle load distributions were obtained and analyzed for the 15 more frequent commercial vehicle categories (representing 97.3% of all the commercial traffic registered). Based on the current Brazilian laws, the results from this study have indicated a significant percentage of violation involving overloaded heavy good vehicles in the highway (23.7%). In general, most axles exceed the legal limits up to 10%, indicating that many vehicles are loaded considering the tolerance as a real gain. A method to identify overloaded truck travel patterns and loading characteristics from available HS-WIM data was proposed. The method is based on Classification and Regression Tree Analysis (CART), an analytical tool. Finally, the traffic data were correlated with the distresses observed in the experimental section constructed closer to the WIM system, where it was simulated the reduction of the useful life of pavement structures considering different load scenarios: (i) real traffic; (ii) traffic in the tolerance (considering the tolerance of 10%); and (iii) legal traffic. it was concluded that the practice of overloading on highways penalizes road transport by accelerating road degradation.

A restauração de pavimentos flexíveis ocasiona, em todo o mundo, problemas ambientais em função do descarte dos materiais provenientes da demolição do pavimento existente, um dos motivos pelo qual a reciclagem de pavimentos tem se mostrado, cada vez mais, uma técnica sustentável e necessária, tanto na manutenção quanto na construção de novas estruturas. Na atualidade, existem as mais diversas técnicas de reciclagem. Neste trabalho, avaliou-se a reciclagem do revestimento asfáltico fresado (RAP) com a adição de agente de reciclagem emulsionado (ARE), estudando a viabilidade de seu emprego em bases asfálticas de pavimentos novos. Por meio de um programa laboratorial de ensaios, foi realizada a análise da estocagem, cura e compactação de uma mistura produzida em uma usina de reciclagem a frio. Para tanto, utilizou-se os parâmetros de módulo de resiliência (MR), resistência à tração por compressão diametral (RTCD) e dano por umidade induzida (DUI). A compactação da mistura no laboratório foi realizada com o Compactador Giratório SUPERPAVE (CGS) e com o Compactador Marshall, sendo avaliada a influência do tempo de estocagem, que é o tempo transcorrido entre a mistura e a compactação (na condição solta), e o tempo de cura após a compactação dos corpos de prova. Os resultados indicam que os parâmetros de MR, RTCD e DUI aumentaram quando a mistura solta permaneceu estocados, pela provável interação entre o agente de reciclagem emulsionado e o ligante asfáltico oxidado do RAP. Foi observado ainda um ganho substancial nos valores de MR e RTCD durante o período de cura, o qual foi pouco influenciado pela estocagem prévia do material. Quanto ao efeito do tipo de compactação, foi possível observar que os corpos de prova produzidos no CGS apresentaram maiores valores de RTCD, MR e DUI em relação aos corpos de prova do compactador Marshall, chegando, inclusive, a dobrar o valor de RTCD após 56 dias de cura. Também foi realizada a construção de dois trechos experimentais com a mistura reciclada estudada, visando o acompanhamento da execução, assim como, o monitoramento do desempenho da mistura, em campo, ao longo do tempo. Constatou-se que foi possível atingir a densidade obtida na compactação Marshall desde que sejam utilizados rolos compactadores adequados e que a espessura da camada seja limitada em até 8 cm. Já os levantamentos deflectométricos realizados durante o monitoramento confirmaram o comportamento mecânico observado em laboratório, indicando o ganho de rigidez da base reciclada ao longo do tempo. Conclui-se, portanto, que o emprego da mistura a frio de RAP com agente de reciclagem emulsionado é uma alternativa viável para a construção de bases de pavimentos rodoviários novos. / Asphalt pavements maintenance produces worldwide residues from milling of deteriorated pavements. Therefore, pavement recycling is a sustainable and necessary technique for new pavement construction and rehabilitation. Nowadays, there many technologies to apply recycling to pavement maintenance. This study evaluated the reuse of the reclaimed asphalt pavement (RAP) mixed with emulsified asphalt recycling agent and its viability to be used as an asphalt base course in new pavements. A laboratory program was used to assess the storage, the cure and compaction of a mix of RAP - emulsified asphalt recycling agent produced in a cold central plant recycling plant (CCPR). The resilient modulus (MR), the indirect tensile strength (ITS) and the moisture induced damage (MID), were used. The compaction at the laboratory was performed using de Superpave Gyratory Compactor (SGC) and the Marshall compactor. The storage period is referred as the time elapsed between the mix and the compaction, in the loose condition. On the other hand, the curing period is associated to the period elapsed after compaction of the specimens. Results showed that the storage period has little effect on the MR, ITS and MID parameters. However, this period was important to likely allow the emulsified asphalt recycling agent to interact with the aged asphalt binder from the RAP. It was observed a substantial increase of MR and ITS parameters during the curing and, again, the storage period had little effect on this. Regarding the compaction method, the SGS specimens had higher values at ITS, MR and MID values, when compared to the Marshall specimens. At the curing time of 56 days, the ITS was doubled at the SGS specimens. Additionally, this study performed the construction of two trial sections with the studied mix. The goal was to register the execution and assess its performance in field during a period. It was verified that in field is possible to reach Marshall densities, since adequate roller compactors are used with specific thickness. The performance of the trial sections was done from FWD testing. These results confirmed the laboratory mechanical behavior of the recycled cold mix, showing that the curing increase of the stiffness. Therefore, it is concluded that the cold mix using emulsified asphalt recycling agent is a viable alternative for the base course construction of new road pavements.