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Recessed pavement markings are consistently utilized to withstand the impact of snowplowing and sanding operations, particularly in regions with cold climates. However, the optimal configuration of recessed pavement markings remains inadequately investigated. The objective of this study is to address this concern by conducting an assessment of the luminance of recessed pavement markings. For considering the visual demands of drivers, a luminance evaluation method based on digital imagery was implemented at first. Recessed pavement markings with various configurations were then prepared, and their luminance was simultaneously measured. The luminance of recessed pavement markings after service simulation was assessed to elucidate the luminance deterioration laws. Finally, the retroreflectivity of recessed pavement markings was evaluated for their comparative analysis and better employment. Based on the luminance deterioration with operation time as an indicator, recessed pavement markings with a thickness exceeding 0.5 mm and flush with the surface exhibited a service life twice as long as conventional pavement markings. The quantitative relationship between critical values of retroreflectivity and luminance was established [retroreflected luminance (RL) of 80 mcd·m−2·lx−1 corresponds to luminance of 200 cd/m2 ], and the minimum RL of recessed pavement markings should be as low as 90 mcd·m−2·lx−1 for practical application. [ABSTRACT FROM AUTHOR]

SBS (styrene-butadiene-styrene block copolymer) is a thermoplastic elastomer with properties most similar to rubber. SBS asphalt modifier is mainly composed of a styrene-butadiene-styrene block copolymer with a certain amount of additives and stabilizers. SBS-modified asphalt binder has always been the most commonly used pavement material both domestically and internationally. However, conventional wet-process SBS-modified asphalt binder requires manufacturers to produce it in advance and transport it to a mixing plant for blending. This has provided an opportunity for unscrupulous businesses to reduce the amount of SBS by adding other substances, allowing inferior asphalt binder to pass inspections undetected. At the same time, conventional wet-process SBS-modified asphalt tends to undergo phase separation and experience a decline in performance as the storage time increases. However, dry-process SBS-modified asphalt can be directly added at the mixing plant, effectively addressing the issues associated with conventional wet-process SBS-modified asphalt. It also helps to reduce environmental pollution to a certain extent. This study investigates the extraction process of dry-process SBS-modified asphalt binder. It clarifies the performance and modification mechanisms of two types of dry-process SBS-modified asphalt binder at different dosages through various testing methods, including basic indicators, rheological properties, infrared spectroscopy, and fluorescence microscopy. The results indicate that due to the incorporation of oil, crosslinker, solubilizer, and other substances into dry-process SBS modifier, there is a small amount of chemical reaction with asphalt in the melting process. The high- and low-temperature properties and fatigue properties of the two dry-process SBS-modified asphalt binders at a 7% dosage are close to wet SBS-modified asphalt binder at a 5% dosage. [ABSTRACT FROM AUTHOR]

The discrete element method (DEM) is one of the most popular methods used to study the performance of pavement materials. However, few studies use the DEM to evaluation the damage performance of asphalt overlays on cement pavements. This paper focuses on the establishment of discrete element models to simulate the reflective crack development of asphalt overlays on cement pavement. Three contact models are selected to realise the pavement structure layer. The results show that under flexural tensile loading and shear loading, the development of reflective cracks can be inhibited with increasing asphalt overlay thickness, while the influence of the interlayer bond strength on the crack development is not obvious. In addition, the flexural tensile load can promote the development of cracks more than shear load. Under the action of thermal fatigue stress, the opening degree of crack displacement increases with the fatigue stress ratio, while the increase in interlayer bond strength can slow down the development and expansion of cracks. Moreover, thermal fatigue stress causes reflective cracks in the overlay to develop earlier and faster. [ABSTRACT FROM AUTHOR]