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• Wax additives, except MS, improve the workability of bitumen. • Wax additives other than SL harden the bitumen and improve rutting resistance. • The chemical interaction between D wax and bitumen is more pronounced than other wax additives. • The effect of wax-based additives on the thermal behavior of bitumen is negligible. • The effect of wax-based additives on the mechanical properties of bituminous mixtures differs according to the type of aggregate used. Although the use of waxes in bitumen modification is not new, the effect of waxes on bitumen and bituminous mixture performance is still a complex subject of debate. This study was carried out to address this complexity and to comprehensively demonstrate the effect of wax-based additives on bitumen and bituminous mixtures. In this context, the systematic quantitative literature review (SQLR) method, which is more objective than the verbal approach, was adopted, and the results were systematically compared based on the numerical data obtained from the studies in the literature. The effect of waxes on the physical, rheological, chemical, and thermal properties of bitumen and the performance characteristics of bituminous mixtures have been evaluated in detail. [ABSTRACT FROM AUTHOR]

Steam-assisted gravity drainage (SAGD) is an important oil recovery strategy for extra heavy oil and bitumen. Operators are under pressure to improve both the environmental and economic performance of SAGD. Through direct visualization, micromodels provide insight into SAGD, but methods to date cannot fully resolve the temperature field which is essential to this thermal recovery process. In this work, infrared and optical pore-scale imaging of the SAGD process within a micromodel with reservoir-relevant pore geometries, fluids, and temperatures was performed, and both recovery and pore-scale fluid behavior was quantified for different concentrations of alkaline additive. Combined microscale flow and high-resolution temperature analysis provide insight into pore-scale phenomena, and shed light on the link between the rapid temperature drop at the steam chamber interface, drainage modes, efficiency and ultimate recovery achieved in SAGD. [ABSTRACT FROM AUTHOR]

Bituminous binders are thermoplastic liquids which behave as viscoelastic materials. Their deformation behavior can be determined by rheological parameters. The changes of both viscous and elastic properties with temperature and time are measured as the response of the material to deformation by periodic forces. The paper presents the most used parameters and rheological properties for the characterization of the rutting resistance of bituminous binders and asphalt mixtures. Rheological properties (G*, δ, η*) are determined for four bituminous binders (unmodified and polymer modified) at temperature 46 – 60 o C (80 o C). And resistance to deformation of asphalt concrete mixtures is determined by rutting test. The higher value of complex shear modulus, the stiffer bituminous binder is able to resist deformation. [ABSTRACT FROM AUTHOR]

Recycled polypropylene (rPP) wastes have been used to improve the high-temperature performance of asphalt. However, the high melting temperature of rPP does not match the conventional mixing temperature of bitumen, resulting in more energy consumption and emissions. Therefore, this study adopted dicumyl peroxide (DCP) to chemically degrade the rPP through a melt-shear processing method to obtain the corresponding modifiers (rPPM) with better flowability at a lower temperature. Torque rheology, melt flow rate (MFR) and thermogravimetry analysis (TGA) characteristics of rPPM incorporated with different dosages (1‰, 3‰, and 5‰) of DCP were compared to that of rPP. Correspondingly, the rPPM modified asphalt (rPPMA) were characterized by penetration, softening point, viscosity, and the dynamic shear rheology (DSR) tests. The TGA test showed that the rPPMs have a lower thermal stability as compared to rPP, and the MFR of rPPM can be up to 1900% larger than that of the rPP. The rPPMs can contribute to increasing the softening point and reducing by almost 50% penetration of virgin binder, which are reflected that they can improve the high-temperature performance of virgin binder. The DSR results stated that rPPM can provide a slightly improved deformation resistance and a lower anti-fatigue characteristic, comparative capacities, as well as a relatively lower deformation resistance and higher fatigue failure to the virgin binder, respectively. Accordingly, 3‰ DCP is optimally recommended to degrade rPP to obtain the modifier for the cleaner production and enhancement of modified binders. [ABSTRACT FROM AUTHOR]

• Cup lump modified bitumen emulsion is prepared using colloid mill method. • The effect of modification and emulsification is studied. • Cup lump modified bitumen emulsion shows enhanced physical and thermal properties. • Elemental analysis results in a stable multi-phase structure and satisfactory compatibility. • CLR Modification and emulsification improves the bee-structure of modified residues. In recent years, bitumen emulsion in cold mix asphalt (CMA) has gained much attention because of its economic and environmental benefits. However, cold mix asphalt faces some major concerns related to its performance. Bitumen modification with polymer is considered to be an effective way to enhance its performance. In the present study, cup lump rubber (CLR) was used as a new modifier for the preparation of new cup lump modified bitumen emulsions (CMBE) to improve its performance. In addition, to further understand the modification mechanism, we discussed the effect of CLR and emulsification on basic engineering properties, chemical composition compatibility, elemental compositions, thermal properties, phase microstructures, surface morphology, and micromechanical features of CMB and its evaporation residues. The results indicate that the basic properties of modified bitumen with CLR were improved, emulsification affects the basic performance to some extent. The inclusion of CLR did not show any significant change in the functional groups of CMB. Moreover, the CLR was dispersed homogeneously and resulted in a stable multi-phase structure of CMB, resulting in satisfactory compatibility. Whereas the emulsification did not affect the elemental composition of evaporation residues of CMB. Furthermore, the thermal stability was enhanced by CLR addition, and the emulsification further improved the thermal properties of all types of bitumen. In addition, the CLR modification and emulsification did not significantly affect the crystalline structure of bitumen and their evaporation residues. Finally, atomic force microscopy results exhibited that the addition of CLR increased the size of bee-structures, which prevented the oxidization of chemical components and enhanced the diffusion ability of bitumen molecules, but the emulsification decreased the size and increased the formation of bee structures, thus improving the physical properties of the evaporation residue of modified bitumen. [ABSTRACT FROM AUTHOR]

In the present work, ground tire rubber (GTR) was mechano-chemically reclaimed at ambient temperature using two-roll mills. Road bitumen and styrene-butadiene-styrene (SBS)-modified bitumen at variable content (in range: 2.5–20 phr) were applied as reactive plasticizers to enhance reclaiming of GTR. For better understanding the plasticizing effect of bitumen on the quality of obtained reclaimed rubber, mechano-chemically reclaimed GTR has been compared with GTR after thermo-mechanical reclaiming via low temperature extrusion (120 °C), which allows generation of high shear forces on GTR. Reclaiming process was evaluated by oscillating disc rheometer measurements, followed by mechanical, physical, thermal, and morphological properties analyses performed on vulcanized reclaimed rubber. The obtained results showed that application of bitumen during mechano-chemical reclaiming of GTR improves processing and prevents oxidation of reclaimed GTR through enhancement of physical and chemical interactions between GTR and bitumen. On the other hand, high shear forces acting on GTR during thermo-mechanical reclaiming caused effective scission of cross-linking bonds, while at the same time an adverse oxidative degradation of GTR occurs. Noticeably, the type of bitumen strongly affected the nature of the interfacial interactions between GTR and bitumen. Plasticization/partial reclaiming of GTR (road bitumen, SBS-modified bitumen) and encapsulation of GTR (SBS modified bitumen) were confirmed by mechanical properties, FTIR, TGA and SEM measurements. [ABSTRACT FROM AUTHOR]

The use of the high modulus asphalt concrete in the base course of airport pavements is not of recent utilization, but at present there is a considerable gap in the regulation for the use of this bitumen. The main objective of this paper is to present the results of the research that has been done using the experimental dynamic modulus of different mixtures of conventional bitumen with different penetration index B40/50, B60/70, B100/150, B150/200 and the high modulus bitumen B13/22 to calculate the percentage of reduction in thickness of the base course in airport pavements when is used High Modulus Asphalt Concrete (HMAC) compare with conventional bitumen mixtures and is also taken into account the temperature. In order to obtain the reduction in thickness depending on the temperature and the use of HMAC, the tests have been performed at the different temperatures −20 °C, −10 °C, 0 °C, 10 °C, 20 °C and all the results in this paper are presented for these temperatures. To perform the calculations of this research the Airbus A380 has been taken as Aircraft Design. [ABSTRACT FROM AUTHOR]

This study identifies a thermal maturity anomaly within the downdip Mississippi Interior Salt Basin (MISB) of southern Mississippi, USA, through examination of bitumen reflectance data from Aptian-age strata (Sligo Formation, Pine Island Shale, James Limestone, and Rodessa Formation). U.S. Geological Survey (USGS) reconnaissance investigations conducted in 2011–2012 examined Aptian-age thermal maturity trends across the onshore northern Gulf of Mexico region and indicated that the section in the downdip MISB is approaching the wet gas/condensate window (R o ~ 1.2%). A focused study in 2012–2013 used 6 whole core, one sidewall core, and 49 high-graded cutting samples (depth range of 13,000–16,500 ft [3962.4–5029.2 m] below surface) collected from 15 downdip MISB wells for mineralogy, fluid inclusion, organic geochemistry, and organic petrographic analysis. Based on native solid bitumen reflectance (R o generally > 0.8%; interpreted to be post-oil indigenous bitumens matured in situ), R o values increase regionally across the MISB from the southeast to the northwest. Thermal maturity in the eastern half of the basin (R o range 1.0 to 1.25%) appears to be related to present-day burial depth and shows a gradual increase with respect to depth. To the west, thermal maturity continues to increase even as the Aptian section shallows structurally on the Adams County High (R o range 1.4 to > 1.8%). After evaluating the possible thermal agents responsible for increasing maturity at shallower depths (i.e., igneous activity, proximity to salt, variations in regional heat flux, and uplift), we tentatively propose that either greater paleoheat flow or deeper burial coupled with uplift in the western part of the MISB could be responsible for the thermal maturity anomaly. Further research and additional data are needed to determine the cause(s) of the thermal anomaly. [ABSTRACT FROM AUTHOR]

Highlights: [•] ATH and EVMT show an obvious synergetic effect on the flame retardancy of bitumen. [•] The thermal degradation of bitumen is restrained by the mixture of ATH and EVMT. [•] The mixed content of ATH and EVMT would better be 15:10 (mass ratio). [ABSTRACT FROM AUTHOR]

Abstract: An important aim of worldwide research engineering is to identify new industries to introduce solar energy installations for average thermal level. Due to the mechanical and thermal properties of bitumen, such as the 44–49 °C softening point of D80/100 type bitumen, this material can be preheated by using solar thermal installations. The Physics Department of “Politehnica” University of Timisoara designed and studied a laboratory installation for preheating in environmental conditions an amount of 25.1 kg of bitumen up to 55 °C per day. The paper developed a previous original research regarding bitumen preheating by using solar energy. The experimental installation was improved and experimental data were statistically processed. The main improvements were based on: [–] increasing the amount of incident solar radiation by: (a) reducing the height of the brick walls and replacing them with transparent glass plates; (b) painting the inner faces of the brick walls in white; [–] cutting down thermal losses by: (a) achievement of the double greenhouse effect in the transparent areas of the installation; (b) change of the brick walls into passive walls. The performances of the installation were improved as follows: [–] increasing time of the bitumen temperature increased from 7 hours to 8 hours, in the interval 8 am–4 pm; [–] bitumen maximum temperature increased from 55 to 63.3 °C; [–] average temperature in bitumen increased from 41.4 to 46.4 °C; [–] maximum efficiency increased from 12 to 14.4%; [–] daily average efficiency increased from 6.3 to 7.3%; [–] maximum difference between the bitumen temperature and environmental one increased from 24 to 32 °C. [Copyright &y& Elsevier]

A global trend for developing sustainable transport infrastructure by adopting various sources of recycled material is being promoted by researchers and media daily. Recycling End of Life Tyres (EOLTs) in the form of Crumb Rubber (CR) builds on decades of past tradition. Local councils in Australia welcome recycling practices and sustainability although a general lack of guidelines is commonly acknowledged for low-traffic roads. This paper evaluates the benefits of low-content crumb rubber modified bitumen (CRMB) for its application on Australian local roads, often exposed to very hot summer temperatures. Blending conditions play a vital role in CRMB; these include temperature, mixing duration and applied shear rate or shear mixer speed. In this study, the influence of blending conditions on the physical, chemical, thermal and rheological properties of low-content CRMB is investigated. Two shear mixing rates (700 and 3500 rpm) and three mixing durations (30, 60 and 90 min) were chosen and rubber-modified blends were prepared with 7.5% CR. Rheological tests such as master curve, black diagram, Cole-Cole analysis, and Multiple Stress Creep Recovery were investigated. It was observed that the mixing duration has minimal effect on low-content CRMB, however, the applied shear rate has an impact in the sense that it produces a relatively stiffer – and oxidised – blend at higher mixing speeds. This was also correlated to the outcome from Fourier Transform InfraRed analysis (FTIR). Overall, the use of low-content CRMB in local Australian roads can significantly improve the rutting performance while facilitating the recycling of end-of-life tyres. • Local councils can benefit by using end-of-life tyres for their road assets. • Low-content crumb rubber-modified bitumen was evaluated for local roads. • Blending conditions affected the chemo-rheological properties of modified bitumen. • Higher mixing speed induces ageing in low-content rubber-modified bitumen. • Addition of small amounts of rubber significantly improves rutting resistance. [ABSTRACT FROM AUTHOR]

• Date palm fibers are durable at bituminous mixture manufacturing temperature. • Fiber addition induced a slight bitumen toughness at service life temperature. • Fiber addition led to complex modulus norm increase at service life temperature. • Date palm fibers significantly decreased binder drainage phenomenon of SMA mixture. • Date palm fibers play the role of reinforcement inside the bituminous matrix. This paper investigated the contribution of plant fibers recovered from date palm waste to modify bitumen properties. Palm fibers were characterized to determine their chemical composition, structure, mass loss by heating and tensile strength and the properties of the bitumen-fiber mixtures were evaluated before and after aging using consistency (penetration, Ring and Ball softening point), rheological and thermal tests. The experiments were completed with binder drainage tests on asphalt mixtures to assess the ability for palm fibers to retain bitumen. The results pointed out that the addition of until 6 wt% fibers to neat bitumen conferred a slightly greater consistency, an increase in viscosity by 50% and complex modulus norm by 40% at service life temperatures, before and after aging. These last trends allow to predict the behavior of the asphalt mixtures towards permanent deformations. Thermal analysis on the different mixtures showed that the addition of fibers induced the increase in bitumen crystallinity. The existence of a semi-crystalline fiber network in the bitumen matrix improves the physico-mechanical characteristics of bitumen. The binder drainage tests performed on asphalt mixtures highlighted bitumen absorption by the fibers; this could be correlated to their microstructure and roughness. The results found in this study are encouraging for a potential use of date palm fibers at asphalt mixture scale. [ABSTRACT FROM AUTHOR]

• The graphene addition increased stiffness at high temperature without excessively stiffening at low temperature. • Graphene addition increased recovery but not comparable to that of polymer modified bitumen. • Thermal conductivity of bitumen increased with graphene addition. • Optimum addition of graphene considering rheological improvements is 1.0 to 1.5%. Rutting in bituminous mixture is one of the most studied research problems in pavements. The increased axle loads and higher temperature form favorable condition for rutting. Efforts have been made to improve rutting resistance of bituminous mixtures using various methodologies. However, with ever increasing global temperature due to climate change, bituminous materials should be modified to adapt for such changes over the long run. One of the methodologies includes use of conductive fillers to modify bitumen. In this study, graphene was used as conductive filler for modifying bitumen to investigate the augmentation in rheological and thermal properties. Two viscosity graded bitumen (VG30 and VG40) were modified with 0.5, 1.0, 1.5, and 2.0% of graphene by weight of bitumen. The control and graphene modified bitumen were subjected to softening point test, storage stability test, frequency sweep, multiple stress creep recovery (MSCR) test, and thermal conductivity test. The isochronal curves indicated reduction in loss factor and phase angle, while increase in complex shear modulus in graphene modified bitumen compared to control binder. The difference in rheological properties between control and modified bitumen were found to be higher at higher testing temperatures. Transition from rubbery state to glassy state was observed at high temperature and high frequency loading, where decrease in phase angle and loss factor was seen. The creep-recovery curves showed higher recovery in graphene modified bitumen at different stress levels, while control bitumen depicted negative recovery with increase in stress levels. The isochronal and MSCR test indicated that an optimum level of graphene was between 1.0 and 1.5% by weight of bitumen, which can be attributed to homogeneous dispersion. Thermal conductivity of bitumen increased with the dosage of graphene as higher number of particles will increase the conducting potential. Overall the results indicated graphene addition in bitumen improved rheological and thermal properties with the potential of reducing rutting in mixtures. [ABSTRACT FROM AUTHOR]

• Bitumen's microstructures are correlated with its bulk thermal and rheological properties. • A critical asphaltene concentration alters virgin ABD from sol-type to gel-type. • Bitumen with incompatible chemical components tends to phase segregate and is more prone to aging. • A higher concentration of asphaltenes leads to more interconnected network structures in bitumen. • Bitumen with a higher concentration of asphaltenes shows a larger glass transition temperature. • Bitumen with a higher concentration of asphaltenes has a larger G ' and a smaller G ". Understanding of how the chemistry of asphalt binders (i.e., bitumens) affects their bulk properties is critical for development of structure-related mechanical models and performance-based specifications for asphalt binders and asphalt-related applications. However, establishing the chemical-mechanical relationships that govern asphalt binders' properties remains a challenge due to binders' complex chemical makeup and the intriguing molecular interactions among binders' various chemical constituents. Here, we investigate the effect of chemical composition on binders' microstructure, thermal, and rheological behavior. Two virgin binders (i.e., ABD and AAD) from different crude oil origins were chosen and a series of derivative binders was made by remixing different weight ratios of the asphaltenes and the maltenes obtained from the two source binders. Thermal and rheological properties of all binders were measured using modulated differential scanning calorimetry and dynamic shear rheometry, respectively. Binders' microscopic characteristics (e.g., microstructures and their contrast in phase images) were evaluated using atomic force microscopy. Our results show that bitumens' characteristic microstructures, as a result of the complex molecular interactions among their various chemical components, are correlated with their bulk thermal and mechanical properties. Notably, the asphaltene/maltene ratio alone cannot predict a bitumen's bulk properties. Instead, a bitumen's distinctive microstructures along with its colloidal index, provide meaningful insights into effect of chemical composition on glass transition, phase stability, and rheological properties of the bitumen. [ABSTRACT FROM AUTHOR]