Asphalt Research Articles

Modeling of Heavy-Oil Flow with Regard to Their Rheological Properties

With the depletion of traditional energy resources, the share of heavy-oil production has been increasing recently. According to some estimates, their reserves account for 80% of the world’s oil resources. Costs for extraction of heavy oil and natural bitumen are 3–4 times higher than the costs of extracting light oil, which is due not only to higher density and viscosity indicators but also to insufficient development of equipment and technologies for the extraction, transportation, and processing of such oils. Currently, a single pipeline system is used to pump both light and heavy oil. Therefore, it is necessary to take into account the features of the heavy-oil pumping mode. This paper presents mathematical models of heavy-oil flow in oil-field pipelines. The rheological properties of several heavy-oil samples were determined by experiments. The dependencies obtained were used as input data for a simulation model using computational fluid dynamics (CFD) methods. The modeling condition investigates the range of shear rates up to 300 s−1. At the same time, results up to 30 s−1 are considered in the developed computational models. The methodology of the research is, thus, based on a CFD approach with experimental confirmation of the results obtained. The proposed rheological flow model for heavy oil reflects the dynamics of the internal structural transformation during petroleum transportation. The validity of the model is confirmed by a comparison between the theoretical and the obtained experimental results. The results of the conducted research can be considered during the selection of heavy-oil treatment techniques for its efficient transportation.

Ecological effects and causal synthesis of oil sands activity impacts on river ecosystems: water synthesis review

Oil sands development in the lower Athabasca River watershed has raised considerable public and scientific concerns regarding perceived effects on environmental health. To address this issue for tributaries and the mainstem of the Athabasca River in the Athabasca Oil Sands Region, the Water Component of the Joint Oil Sands Monitoring (JOSM) plan produced monitoring assessments for seven integrated themes: atmospheric deposition, tributary water quality, river mainstem water quality, groundwater quality and quantity, water quality and quantity modelling, benthic invertebrate condition, and fish health. Our review integrates and synthesizes the large and diverse datasets assembled in the seven JOSM theme assessments to (i) evaluate possible environmental effects based on known sources and candidate proximal causes and (ii) determine the importance of cause-and-effect pathways related to contaminant, sediment, and nutrient inputs. Although JOSM research identified ecological effects that appear to be associated with contaminant exposure, the source of this exposure is confounded by co-location of, and inability to differentiate between, oil sands operations (principally released by atmospheric emission) and inputs from the natural bitumen outcrops (e.g., erosional material transported by surface and groundwater flows). Nutrient enrichment from treated municipal sewage effluent was the dominant ecological effect observed for the mainstem Athabasca River, associated with increased fish size and changes in invertebrate assemblages, likely because this pollution source is discharged directly into the river. If the direct release of treated oil sands process water occurs in the future, then the potential ecological impact of these direct industry releases will need to be evaluated carefully. The ecological causal assessment method proved to be a useful tool for better understanding how stressor sources relate to ecological effects through candidate proximate causes. Factors that confound our ability to assess the ecological effects of oil sands development focus on our inability to adequately differentiate between contaminants supplied from natural and anthropogenic contaminant sources. Our causal synthesis identifies options for changes in future monitoring to better anticipate and detect degradation in the ecosystem health of the lower Athabasca River and its tributaries.

Preliminary study of hot mix asphalt containing water treatment and sewage sludge

Preliminary study of hot mix asphalt containing water treatment and sewage sludge

抗剥落剂对沥青胶结料及沥青混合料路用性能影响分析

抗剥落剂对沥青胶结料及沥青混合料路用性能影响分析

基于注浆技术的沥青路面病害综合处治方法研究

基于注浆技术的沥青路面病害综合处治方法研究

云平台监控技术在沥青路面施工全过程中的应用研究

云平台监控技术在沥青路面施工全过程中的应用研究

再生沥青混合料级配组成设计以及路用性能研究

再生沥青混合料级配组成设计以及路用性能研究

Economic and environmental benefits of thin bituminous surface pavements over thick bituminous surface pavements

The design of bituminous pavements, using mechanistic-empirical design method, involves the selection of thicknesses of the bituminous layer and the granular layers to keep the strains at critical locations of the pavement structure within the allowable limits arrived from performance equations. The tensile strain under the bituminous layer defines the fatigue life, and compressive strain on top of the subgrade defines the rutting life of the pavement based on the performance equations adopted. It is generally considered that increasing the thickness of the bituminous layer decreases the strain at the bottom of bituminous (binder) layer. So, most of the pavement designers increase the thickness of the bituminous layer to restrict the strains. However, this is not always true. In fact, the tensile strain at the bottom of the bituminous layer increases with the increase in the thickness of bituminous layer up to a critical thickness and then slowly starts decreasing as the thickness further increases. The critical thickness of bituminous layer ranges between 50 mm and 100 mm. In the majority of the cases, the critical tensile strain under the bituminous layer corresponding to the thicknesses of the bituminous layers of 25 mm and 200 mm are very close. Apart from the economy, the problem of mix rutting is greatly minimized in the case of thin bituminous surfacing (TBS). The issues in rehabilitation and recycling of pavement materials are very less as the granular layer can be reused without much processing requirements.

Live-load distribution of an adjacent box-beam bridge: Influence of bridge deck

Leaking longitudinal joints are commonly observed in adjacent box-beam bridges and are often associated with an assumed loss of load distribution at the leaking joint. To address the lack of test data and general uncertainty in analyzing deteriorated concrete structures, a series of load tests was conducted to determine the load distribution of a deteriorated adjacent concrete box-beam bridge. Load distribution was investigated for the existing structure with leaking joints as well as for the structure following rehabilitation with a noncomposite reinforced concrete deck. The bridge was tested in four conditions: as built, after removal of the bituminous wearing surface, after the shear keys were disabled, and with a reinforced concrete deck installed. Load distribution was assessed for each condition, and the results were compared with design equations. In addition to assessing load distribution of the existing bridge, the results of this study can serve as support for the use of a concrete deck as a rehabilitation strategy to restore load distribution or function as the primary load distribution mechanism of an adjacent box-beam bridge.

Chemical composition (saturate fraction) of western Iraq natural bitumen

This study aims to explore the main components of bitumen in western Iraq as a natural resource of heavy oil. The raw bitumen studied was fractionated into asphaltene and maltene, and then the maltene was separated into saturated, aromatic and polar fractions. Fourier Transform Infrared (FT-IR), 13 C NMR, Scanning Electron Microscopy–Energy Dispersive (SEM–EDX) and Gas Chromatography (GC) were used to characterize the organic components of the bitumen. Hypothetical average molecules have been diagnosed including bitumen, asphaltene and aromatic according to 13 C NMR methods. The results indicate that the saturated, aromatic and polar compounds in bitumen are 8.24%, 55.67% and 9.93% respectively, while the asphaltene is 26.56%. The bitumen studied contains a relatively high amount of asphaltenes and aromatics fractions, potentially due to a thermal maturation of organic material in the well. However, it may be modified as crude oil derivatives because it contains certain aliphatic hydrocarbons.

Geoecological problems of development of heavy oil and natural bitumen deposits

Geoecological problems of development of heavy oil and natural bitumen deposits

A comprehensive investigation of the effect of mineral additives to bituminous concrete

Research efforts to employ sustainable materials for road construction have been on the rise in recent years. In particular, the use of polymers as additives in asphalt mix has been actively explored by several researchers. Bituminous pavementsnormally constructed in India, have increasing number of premature failures, due to increase in traffic density and noteworthy variations in road temperatures. The modified binders have proven to improve numerous properties of bituminous surfaces such as temperature susceptibility, fatigue life, creep, resistance to permanent deformation and rutting. The present study has focussed on the experimental investigations conducted to evaluate the influence of mineral additives, such as wollostonite and Rice Husk Ash (RHA) on Indirect Tensile Strength (ITS) and Tensile Strength Ratio (TSR) of bituminous concrete (BC)maintaining uniformity of aggregate properties.The results establish that the bituminous concrete blends modified using rice husk ash at 20% and wollostonite at 8%, with hydrated lime are most suitable for practical applications.

Avaliação da drenabilidade de pavimentos asfálticos em Barra do Garças, Mato Grosso, Brasil

No que se refere às condições de segurança dos pavimentos, a drenabilidade merece atenção pois expressa a facilidade ou a dificuldade da ocorrência do fenômeno de hidroplanagem. Na presente pesquisa buscou-se estudar a drenabilidade de pavimentos urbanos avaliando a capacidade drenante de uma superfície pavimentada com concreto betuminoso usinado a quente (CBUQ) e outra em tratamento superficial duplo com capa selante (TSD), com um drenômetro construído seguindo as orientações de Lima e Dalla Riva (2014). Com os dados de vazão média para cada estação avaliados juntamente com os dados do ensaio de mancha de areia obtidos por Domingues (2018), foi possível obter uma equação que relaciona os resultados de drenabilidade com a textura do pavimento. Ao correlacionar essa equação ajustada, com os intervalos definidos por Pasquet (1968 apud CUBAR; DALLA ROZA, 2015), a Rua Coronel Elias Galvão recapeada com CBUQ, apresentou uma textura superficial média, indicada para vias com velocidade no intervalo de 80 a 120 km/h e o revestimento com TSD da Rua Presidente Kennedy foi classificado como muito grosseiro ou muito aberto, indicado para casos especiais que consistem em áreas com alto risco de hidroplanagem. Apesar de não apresentarem valores de drenabilidade (macrotextura) ideais segundo o Departamento Nacional de Infraestrutura de Transportes (DNIT), as condições das pistas avaliadas não oferecem risco à segurança do usuário, uma vez que são destinadas ao tráfego urbano.

Finite element and experimental validation of sample size correction factors for indentation on asphalt bitumens with cylindrical geometry

Characterization of asphalt bitumens by indentation has been traditionally carried out neglecting the effect of boundary conditions. Recent theoretical and experimental works demonstrated that the effect of sample size on indentation of asphalt bitumens can be significant.In this paper, sample size correction factors for indentation with cylindrical geometry are obtained using finite element simulations. The correction factors calculated for finite sample depth matched the ones obtained analytically in previous research. The adjustment factors for finite lateral dimensions obtained through finite element were, however, significantly higher than the previously obtained by analytical means. The main reason for the difference is that the volumetric effects captured by the finite element analysis were neglected in the previous analytical approach.Additionally, indentation testing was carried out on an unmodified asphalt bitumen using nine different sample sizes. The raw indentations measured on the different sample sizes varied significantly among each other. When the indentations were corrected for sample size, the adjusted results from all samples were considerably similar to each other, indicating that the correction factors accounted properly for the sample size effects on indentations.Creep compliances in shear were obtained from the indentations corrected for sample size. The results matched the creep compliance measured using a dynamic shear rheometer (DSR). On the contrary, the creep compliances obtained from the raw indentations were less than half the magnitude of the creep compliance measured with the DSR. These results confirm the significance of the sample size effects on asphalt bitumen indentation. They also validate the sample size correction factors obtained for indentation of asphalt bitumens with cylindrical geometry.

Application of Aromatic and Industrial Solvents for Enhancing Heavy Oil Recovery from the Ashalcha Field

Nowadays, there is a significant increase in the share of unconventional oil reserves such as heavy and extra-heavy oils as well as natural bitumen among the total balance of extracted petroleum fe...

Trace metals as indicators of tree rooting in bituminous soils

AbstractIn some reclamation practices, following bitumen mining in the Canadian Boreal forest, overburden containing low concentrations of hydrocarbons (<8% of bulk soil volume) is buried under suitable soils. Residual hydrocarbons may influence the growth of trees used in afforestation of reclaimed sites, thus determining whether roots interact with buried bitumen is a key to predicting reclamation success. As the organic fraction of bitumen is enriched in vanadium, nickel, molybdenum, and rhenium, dendrochemistry may be a method to determine whether tree roots are interacting with bitumen without disturbing soils. We analyzed trace concentrations of these metals in soil, soil pore water, and tree cores of Pinus banksiana growing on natural bitumen deposits and sites free of bitumen. If roots are present within bitumen and passively uptake trace metals during water transport and wood growth, metals enriched in bitumen should be present in higher concentrations in the woody tissue of trees growing in bituminous soils compared to trees growing in bitumen‐free soils. Concentrations of nickel in trees growing on shallow bitumen deposits were approximately 3× higher than those growing in bitumen‐free soils. The concentration of vanadium (1.33 μg kg−1 in younger wood and 3.21 μg kg−1 in older wood) was also elevated in trees on bituminous sites, though not significantly. Molybdenum concentrations decreased by ~25% in trees growing on bituminous sites, likely an outcome of soil pH. This research supports the use of dendrochemistry to investigate, and potentially monitor, tree rooting at depth in substrates with signature metals.

ИССЛЕДОВАНИЕ БИТУМНО-ВЕРМИКУЛИТОВЫХ МАСТИК И АСФАЛЬТОБЕИОНОВ ДЛЯ ДОРОЖНОГО СТРОИТЕЛЬСТВА

В работе исследованы битумно-вермикулитовые композиции, мастики и асфальтобетонные смеси, предназначенные для дорожного строительства. Проведены исследования по получению и испытаниям битумно-вермикулитовых композиций с использованием битумов нефтяных дорожных марок БНД 90/130 и БНД 60/90 и вспученного вермикулитового песка фр. 0,6 – 1,0 мм. Разработаны и испытаны в дорожных условиях битумно-вермикулитовые мастики, асфальтобетонные смеси (по ГОСТ 9128) и показана их эффективность при ремонте асфальтобетонных покрытий в условиях эксплуатации автомобильных дорог на севере Тюменской области.

Nondestructive Analysis of Mummification Balms in Ancient Egypt Based on EPR of Vanadyl and Organic Radical Markers of Bitumen.

The black matter employed in the funeral context by ancient Egyptians is a complex mixture of plant-based compounds with variable amounts of bitumen. Asphaltene, the most resistant component of bitumen, contains vanadyl porphyrins and carbonaceous radicals, which can be used as paramagnetic probes to investigate embalming materials without sample preparation. Electron paramagnetic resonance (EPR) at the X-band, combining in-phase and out-of-phase detection schemes, provides new information in a nondestructive way about the presence, the origin, and the evolution of bitumen in these complex materials. It is found that the relative EPR intensity of radicals and vanadyl porphyrins is sensitive to the origin of the bitumen. The presence of nonporphyrinic vanadyl complexes in historical samples is likely due to the complexation of VO2+ ions by carboxylic functions at the interface between bitumen and other biological components of the embalming matter. The absence of such oxygenated vanadyl complex in natural bitumen and in one case of historical human mummy acquired by a museum in the 19th century reveals a possible, nondocumented, ancient restoration of this mummy by pure bitumen. The linear correlation between in-phase and out-of-phase EPR intensities of radicals and vanadyl porphyrins in balms and in natural bitumen reveals a nanostructuration of radicals and vanadyl porphyrin complexes, which was not affected by the preparation of the balm. This points to the remarkable chemical stability of paramagnetic probes in historical bitumen in ancient Egypt.

Investigating aged binder mobilization and performance of RAP mixtures for surface courses

Pavement engineering practice still deals with a set of restraints regarding the use of RAP, mainly in the case of bituminous surface courses. The main objectives of this paper are to assess: (a) the influence of the rejuvenator and the degree of aged binder mobilization on the homogeneity of bituminous mixtures; and (b) the performance and durability of bituminous mixtures for surface courses with 25% RAP. The laboratory investigation studied an AC 14 surf 35/50 considering two mixture compositions: a reference mixture with virgin constituents; and a mixture containing RAP and a rejuvenator agent. The study was focused on the mechanical and functional behaviours, as well as on the short- and long-term ageing performance of mixtures. An experimental protocol for RAP fractioning and rejuvenator addition was established to achieve a better control of the final mixture quality. The aged binder mobilization was more efficient when RAP was heated. The RAP mixture revealed a good performance in terms of permanent deformation, water sensitivity, stiffness, and fatigue. The incorporation of fractionated RAP allowed to have a mixture with good surface characteristics. Aged RAP mixture performance envisioning good long-term behaviour. Regarding the promotion of the circular economy, this investigation clearly demonstrated that mixtures with a 25% RAP incorporation can be currently used in surface courses.

Studying the regularities of oxidative catalytic cracking of vacuum distillates

Improving the efficiency of processing heavy oil residues into light petroleum products and raw materials is an urgent task for Kazakhstan and other countries that produce and consume petroleum products. Really the share of heavy oil and natural bitumen in the balance of hydrocarbon raw materials produced will continuously increase. The aim of the study was preparation of catalysts based on Taizhuzgen zeolite and Narynkol clay (Kazakhstan) and determination their efficiency in the process of oxidative cracking of vacuum distillates of Atyrau and Zhetybai oil. The IR spectra of the obtained gasolines indicate that the reactions of incomplete oxidation of hydrocarbons in the course of oxidative cracking practically do not occur. At low volume feed rates of the initial substance to the reactor, the yield of diene and cyclodiene hydrocarbons in the presence of air additives significantly increases in comparison with cracking carried out without air additives to the reactor. The direction of the oxidative cracking process changes with an increase in the volume rate of the suspension feed. Obviously that the air of definite concentrations in the reactor contribute to a deeper destruction of the hydrocarbons of the vacuum gas oils investigated.