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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]

• 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]

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]

• 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]