The physical, chemical and morphology characteristics of the ceramic source enable its waste to be a novel modifier for bitumen. This study employed the top-down approach via dry grinding in a ...mechanical ball mill to generate a nanoceramic powder (NCP). As a result, NCP was successfully generated with an optimum duration of 15 h and optimum Ball-to-Powder Ratio (BPR) of 10:1. The results also indicated that the particle size of NCP was significantly decreased to less than 100 nm. XRD pattern and Scanning Electron Microscopy (SEM) of the NCP-modified bitumen (NCPMB) indicated good dispersion of the NCP within the bitumen matrix. This improvement led, in turn, to decrease in the penetration and to increase in softening point and rutting resistance factor (G*/sin δ) of the NCPMB. In addition, the contact angle results indicated that the presence of NCP increased the number of heteroatoms and, hence, the polarity of the modified bitumen, thereby improving the adhesion of bitumen toward the aggregate. A small difference in softening point between the top and bottom is an indicator of NCPMB with good high-temperature storage stability. Asphalt Pavement Analyser (APA) outcomes reaffirmed the structural improvement of the modified asphalt mixture and rutting resistance was increased.
Asphalt pavements absorb and store more heat than natural surfaces. Thus, high temperatures are emitted from conventional asphalt pavements, subsequently releasing heat into the atmosphere and ...contributing to the urban heat island (UHI) phenomenon. Several cool pavement strategies, including the provision of additives and materials, surface coating and layer design, have been introduced to reduce the impact of UHI. This article provides a detailed review of the thermal properties of these mitigation measures in the context of cool asphalt pavements. The literature can be divided into three segments. The first segment discusses the impact of pavements on UHI and heat transfer mechanisms in pavements. The second segment focuses on various thermo physical properties that play an important role in mitigation measures; these properties include albedo (α), emissivity (ε), solar reflective index, thermal conductivity (k), specific heat capacity (Cp) and thermal diffusivity. The third segment discusses cool asphalt pavement strategies which specifically cover the ability of the pavement to absorb and reflect solar energy on the basis of the materials and treatments used. The literature reveals that cooling strategies that deal with the pavement surface are important due to its direct incident solar effect, which depends on surface colour, material, shape and roughness. By using high-albedo and high-emissivity surfaces, the pavement can store less heat and lower the surface temperature. These results can also be achieved by designing the materials and pavement layers with low thermal conductivity and high specific heat capacity to reduce thermal diffusivity and pavement temperature and thus combat the heat radiated by the asphalt pavement.
•Physical and thermal properties of pavement influence the heat transfer.•High emissivity and albedo are preferred for cool pavement design.•Reflective and permeable pavements are significant for cooling strategies.•Pavement coating is the most preferred technique for reflective pavement.
This research addresses the significant challenge posed by early water damage in highway asphalt pavement, a critical concern affecting pavement service performance. To counteract this issue, the ...utilization of anti-stripping agents in asphalt is explored as a highly effective technical intervention. In this investigation, a carefully selected amine-free additive was employed to modify the asphalt binder. A comprehensive array of physical and rheological tests, covering aspects such as storage stability, penetration, softening point, ductility, elastic recovery, rolling thin-film oven, retained penetration, the ductility of residue, and rotational viscometer assessments, were conducted to examine the multifaceted impact of the anti-stripping agent on the asphalt binder. Additionally, we assessed the asphalt mixture’s sensitivity to moisture through Marshall stability tests after conditioning for 40 min and 24 h, followed by an enhanced immersion test and moisture susceptibility measurement. The results reveal a nuanced interplay of chemical and physical mechanisms influencing the behavior of the asphalt binder. Notably, the incorporation of an anti-stripping agent at a concentration of 0.25–0.5% (by weight of asphalt binder) led to a substantial improvement in the tensile strength ratio (TSR) to 94.9%, a noteworthy enhancement compared to the 80.6% observed with virgin asphalt mixture. Furthermore, the retained stability index (RSI) exhibited a remarkable increase to 98.1%, surpassing the 87.6% recorded for virgin asphalt. This study not only provides crucial insights into the intricate dynamics of asphalt binder performance but also emphasizes the pivotal role of anti-stripping agents in augmenting the structural integrity and resilience of asphalt pavement.
This investigation is centered around the application of warm mix asphalt (WMA) technologies to address workability concerns linked to rubberized asphalt binders. The primary aim of incorporating ...crumb rubber (CR) and WMA additives is to establish a robust paving method that fosters energy conservation, efficient waste management, noise reduction, and improved overall performance. The current study aims to comprehensively characterize and differentiate the physical attributes of rubberized asphalt binders by employing three distinct WMA additives: Sasobit, Cecabase RT and Rediset WMX. These additives are introduced into eight unique asphalt binders. Laboratory assessments are carried out to evaluate the workability and physical properties of these binders. The evaluation encompasses penetration, softening point, penetration index, penetration viscosity number, storage stability, ductility, viscosity, and stiffness modulus analyses. The findings indicate that the rubberized asphalt binder enhanced with Sasobit demonstrates the highest levels of both hardness and softening point in comparison to asphalt binders supplemented with alternative WMA additives. The evaluation of storage stability underscores the satisfactory stability across all modified asphalt binders. Both the unmodified and modified binders meet the requirements stipulated by the ductility test; the rubberized asphalt binder modified with Rediset falls short. The rubberized asphalt binder improved with Sasobit displays the most notable enhancement in workability. Furthermore, the blend of crumb rubber and Sasobit binder reveals the highest stiffness modulus values under conditions of intermediate and high temperatures with 1.88 and 0.46 MPa, respectively. In summation, the rubberized asphalt binder incorporating crumb rubber with Sasobit showcases superior improvements in both stiffness and workability compared to counterparts modified with Cecabase RT and Rediset WMX.
The high surface temperature of the conventional asphalt pavement due to high solar energy absorption could contribute to the Urban Heat Island (UHI) phenomenon. Concurrent with this phenomenon, ...rapid urbanization and industrial development have led to a large quantity of waste products available for disposal or recycling. Therefore, this study investigates the thermal performance of selected waste materials that could potentially be used as aggregate in asphalt pavement to combat the problem of increased pavement surface temperature. A number of waste materials were selected for the thermal performance measurement and compared to granite as conventional aggregate. The cylindrical and slab samples of AC14 dense graded asphalt were prepared for the different selected aggregate types. The samples were then measured for solar reflectance using Spectroradiometer. In addition, the surface and internal temperature profiles of the samples were monitored using infrared camera and thermocouples, respectively, in exposed environments. Based on the results, it is possible to use some of the waste materials as an aggregate replacement in order to reduce the UHI impact.
Fine aggregate is a main asphalt component, which provides essential effect on the performance of asphalt mixture. Major consumption of aggregate for construction has caused depletion of natural ...resources and needs for alternative aggregate. Industrial wastes generated from manufacturing processes were laboratory evaluated as alternative fine aggregates in hot mix asphalt with variation in hardness, density and water absorption. Detailed design of the asphalt containing the potential aggregates of garnet and coal bottom ash was prepared and compared with the conventional granite aggregate using Marshall mix design method. The asphalt mixtures were tested for volumetric properties and stability under different ageing conditions. Results showed that fine aggregate has considerably affected the asphalt properties. Garnet improves the asphalt density and stability compared with other fine aggregates under both ageing conditions, thereby suggesting the suitability of garnet as an aggregate in asphalt pavement.
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