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Nuclear magnetic resonance (NMR) images were obtained on asphalts which were dissolved in toluene and titrated with iso-octane to the point of onset of flocculation. When iso-octane was added to the asphalt and the mixture stirred, asphaltene precipitation proceeded in a normal fashion. However, when the titrant was added slowly to minimize mixing at the iso-octane-asphalt-toluene interface, the images...
Nuclear magnetic resonance (NMR) images were obtained on asphalts which were dissolved in toluene and titrated with iso-octane to the point of onset of flocculation. When iso-octane was added to the asphalt and the mixture stirred, asphaltene precipitation proceeded in a normal fashion. However, when the titrant was added slowly to minimize mixing at the iso-octane-asphalt-toluene interface, the...
In this study the rheological, physical, and chemical properties of asphalts procured from Ras Tanura, Riyadh, Kuwait, and Bahrain refineries were evaluated. The rolling thin-film oven (RTFO), termed as short-term aging, and the pressurized aging vessel (PAV), termed as long-term aging, tests were used to simulate asphalt aging. Viscosity, penetration, softening point, and weight loss tests were applied...
In this work, the chemical properties of a commercial grade Saudi Arabian asphalt procured from Ras Tanura refinery were evaluated. The rolling thin film oven (RTFO), termed as short-term aging, and pressurized aging vessel (PAV), termed as long-term aging, tests were used to simulate the laboratory aging of this asphalt. It was found that PAV has more severe effects on the chemical properties of...
The X-ray diffraction (XRD) method was employed to investigate and compare some of the crystallite parameters and aromaticity of asphaltenes obtained from fresh and aged Arabian asphalts, procured from Ras Tanura (RT) and Kuwait (KW) refineries. A few crystallite parameters in the polar aromatics, naphthene aromatics and saturate fractions of these Arabian asphalts were also determined. The results...
Blends of 75% gasoline and 25% ethanol (E25) are unique fuels used in Brazil. The natural E25 oxidation process due to aging under atmospheric conditions has been investigated. To evaluate aging effects on the properties of commercially available fuel blends, two samples of regular E25, one sample of regular E25 with additives, and one sample of high octane E25 were tested. The samples were analyzed...
Rejuvenators are products designed to restore original properties to aged (oxidized) asphalt binders by restoring the original ratio of asphaltenes to maltenes. These products are used to retard the loss of surface fines and to reduce the formation of additional cracks; however, for a rejuvenator to be successful, it must penetrate the pavement surface. Besides, application of a rejuvenator will also...
A simple, robust, and sensitive technique to determine the distribution of short–chain fatty acids (SCFA) in biodiesel and their relative contribution to the total acid number (TAN) was developed. The method is based on miniaturized volume extractions in order to (1) remove the diesel background and transfer the acids to an aqueous phase for robust ion exclusion chromatography with conductivity detection,...
The stability and activity of Cu/ZnO/Al 2 O 3 catalysts in liquid phase methanol synthesis have been enhanced by using microwave irradiation in precipitation and aging processes. The phase composition of precursors and the microstructure of calcined CuO/ZnO/Al 2 O 3 catalysts were characterized by XRD, FT-IR, DTG, HR-TEM, H 2 -TPR and XPS, and the catalytic...
An experimental study is conducted to determine the wax deposition potential of three waxy crude oils during laminar flow in a pipeline system. The Taguchi experimental design approach is used to evaluate the influence of important operating factors such as inlet crude oil temperature, temperature difference between the oil and the pipe wall (ΔT), the flow rate of crude oil, wax content and time on...
The impact of different fuels, gasoline, two ethanol–gasoline blends (E5, E85) and compressed natural gas (CNG), as well as lubricating oils on the aging behavior of Three-Way-Catalysts (TWCs) has been investigated with six state-of-the-art passenger cars over 40,000km under real world driving conditions. For the study, all vehicles have been equipped with identical TWCs. During the investigation...
Environmental exposure affects asphalt mixture performance. Using a Dynamic Shear Rheometer (DSR), we determined there was a correlation between the environmental aging of Colombian asphalt binders AC-20 and AC-30 and changes in their rheological properties. We aged asphalts using the Rolling Thin Film Oven (RTFO) test and the Pressure Aging Vessel (PAV), as well as an ultraviolet (UV) chamber designed...
An increasing use of renewable fuels in the transport sector reduces the dependency on fossil oil and lowers the emission of greenhouse gases. This is a prime political and economic goal in Europe and also in many other parts of the world. In the diesel fuel sector, especially fatty acid methylesters are introduced as renewable fuels. This so-called biodiesel is mostly added to common diesel fuel...
Composite additives of ethanol, acetonitrile, and methyl acetate were added to bio-oils to assess the effects of these additives on stability of bio-oil using D-optimal experimental mixture design (DMD). A systematic analysis of the influence of different proportions of composite additives on bio-oil properties such as viscosity, water content and pH was carried out. The results showed that bio-oil...
Styrene-butadiene-styrene copolymers (SBS) modified asphalt has been widely used for extending the service life of pavement. Understanding the natural weathering mechanism of SBS modified asphalt (SBSMA) is useful for both the extension of service life and recycling SBSMA pavement. The natural weathering process of base asphalt (BA) and SBSMA is traced by characterizing the rheological and structural...
Bio-derived rejuvenating agents have the potential to enhance the rheological properties of the vacuum tower bottoms left over from the crude oil refining process. Enhancement of the rheological properties allows the stiff vacuum tower bottoms to be used as an asphalt binder in hot mix asphalt. This study investigates the use of several experimental bio-derived rejuvenating additives and compares...
This paper presents analysis of chemical changes in asphalt binder samples that were aged using an accelerated weathering tester, which involves UV radiation and direct aging of the binder surface. It also provides a comparison with chemical changes in the same binders but aged with standard methods. Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) results show that the...
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