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Devulcanized rubber-modified asphalt (DRMA) possesses broad application potential due to its environmental friendliness and exceptional performance. However, the relationship between the rubber devulcanization degree, rubber content, and the modification effect of asphalt binder has not been clearly revealed. In this work, DRMA with different rubber devulcanization degrees and contents was prepared. The storage stability and rheological properties of several asphalt binders were evaluated, and the interaction mechanism between different devulcanized rubber (DVR) and asphalt was also detected. The storage stability of DRMA increased with the rubber devulcanization degree and decreased with the DVR content. The rheological test results demonstrated that under the same rubber devulcanization conditions, the elasticity ratio, rutting resistance, and fatigue resistance of the ML40 series was enhanced continuously, while the above properties of DRMA of the other series were enhanced and then weakened with the rubber devulcanization degree. Additionally, the DRMA of the ML60 series had a superior elasticity ratio and rutting resistance when the DVR content was the same. The low-temperature performance of DRMA increases with the rubber devulcanization degree and DVR content. [ABSTRACT FROM AUTHOR]

The residue of emulsified asphalt is its final state when it becomes part of an asphalt mixture. Therefore, the mechanical properties of the residue have a significant impact on the performance of emulsified asphalt mixtures. Dynamic shear rheological tests and fluorescence microscopy were conducted to explore the effects of emulsification and aging on the rheological properties and micro-morphology of emulsified asphalt residue. The results of both the temperature sweep and multiple stress creep recovery tests indicated that the emulsification of the asphalt had different effects on the rheological properties of the base asphalt and the styrene-butadiene-styrene (SBS)-modified asphalt. For the base asphalt, emulsification increases the complex shear modulus by about 5% and reduces irrecoverable creep flexibility by 30%. However, the physical grinding effect of the colloid mill during the emulsification process could destroy the internal spatial network structure of SBS, leading to a reduction in the complex shear modulus by about 5% and a 10% increase in irrecoverable creep flexibility. This phenomenon is similar to the aging of SBS-modified asphalt, which, in turn, leads to a decline in the performance of emulsified SBS-modified asphalt residues. [ABSTRACT FROM AUTHOR]

Despite their effectiveness in preventing icing, hydrophobic coatings possess drawbacks such as susceptibility to detachment and limited wear resistance, leading to inadequate longevity in melting ice/snow. To enhance the surface stability and durability of superhydrophobic coatings, nanoparticle/epoxy formulations were developed using three types of nanoparticles, two dispersion techniques, three application methods, and two epoxy resin introduction approaches. Testing encompassed water contact angle measurements, assessment of ice adhesion force, and determination of icing rates on asphalt concrete coated with these hydrophobic formulations. Fourier-transform infrared spectroscopy was employed to analyze the molecular structures of the coatings, while scanning electron microscopy facilitated observation of the surface morphology of the hydrophobic coatings. The findings indicated that nano-ZnO, TiO2, and SiO2 particles could be modified into hydrophobic forms using stearic acid. Application of the hydrophobic coating improved the concrete's hydrophobicity, reduced ice adhesion strength on both concrete and asphalt, and delayed the onset of icing. Furthermore, optimal dosages of stearic acid, nanoparticles, and epoxy resin were identified as crucial parameters within specific ranges to ensure the optimal hydrophobicity and durability of the coatings. [ABSTRACT FROM AUTHOR]

Summary: Eucalyptus is one of the most widespread genera around the world and a key element in recent wildfires. In a Eucalyptus forest, the accumulation of litter builds up a ground fuel layer that can support both flaming and smouldering wildfires. This work investigates the smouldering wildfire on leaf, bark, and twig beds (bulk density: 70‐140 kg/m3) of Eucalyptus species. Two‐stage smouldering spread processes are observed. The first‐stage smouldering fire has the peak temperature of 600°C‐700°C and spread rate of 5‐9 mm/min. The measured emission factors are 1000‐1500 g/kg (CO2), 180‐450 g/kg (CO), 9‐16 g/kg (CH4), and 2‐6 g/kg (H2), respectively. The CO/CO2 ratio ranges from 0.15 (leaf) to 0.8 (bark). Laboratory experiments demonstrate that the smouldering fire spread is slower in leaf than those in bark and twig. The burning of stringy barks is less complete, compared to smooth barks. For leaf and twig beds, the influence of Eucalyptus species and heating value on smouldering fire is negligible. This is the first work to reveal smouldering fire behaviors on different Eucalyptus litter fuels and provides valuable information for understanding the effects of Eucalyptus species and plant parts on smouldering combustion. [ABSTRACT FROM AUTHOR]