Hong Zhang

1. Asphalt pavement is widely used in the construction of high-grade highways and urban roads because of its advantages such as low noise, good smoothness, and high driving comfort (Indacoechea-Veg...

In response to the shortcomings still observed in polyethylene (PE)/ethylene-vinyl acetate (EVA)/styrene-butadiene-styrene (SBS) composite modified bitumen regarding storage stratification and low-temperature performance, this paper further introduces furfural extract, elemental sulphur, stabilisers and Z-6036 into this ternary system, and employs orthogonal design to screen the additive ratios. Tests were conducted on conventional physical properties, rotational viscosity, dynamic shear rheology and bending beam rheology, focusing on the material’s temperature sensitivity, rheological behaviour, low-temperature creep resistance and phase characteristics. The modification effects were analysed using fluorescence microscopy, scanning electron microscopy and infrared spectroscopy. Compared with the control group composed of 4% PE, 4% EVA and 2% SBS, the samples obtained from the orthogonal design showed an increase in elongation at 5 °C ranging from 52.5% to 213.9%; the difference in softening points decreased from 35.2 °C to a minimum of 0.1 °C, indicating improved storage stability. The temperature sensitivity of all sample groups was reduced, with the optimal group achieving a VTS of −0.4413, representing a 46.7% improvement over the control group. At −12 °C, the m-values of all nine orthogonal samples were higher than those of the control group, with seven groups reaching m ≥ 0.3, indicating improved low-temperature stress relaxation capability. A comprehensive analysis of the experimental results indicates that the selected chemical additives are beneficial for optimising the dispersion state and compatibility of the SBS/PE/EVA ternary modified bitumen, whilst also balancing rheological properties and low-temperature crack resistance to a certain extent. Microscopic and spectroscopic analyses further suggest that internal interactions within the system have been enhanced and the phase distribution has become more uniform; however, the current evidence is insufficient to conclusively determine that a specific form of chemical cross-linking reaction has occurred.

Conventional rubber powder modified asphalt is widely used, but there are drawbacks such as high viscosity, processing difficulties, and poor storage stability, which are avoided by using desulfurized rubber powder. In this study, waste desulfurized rubber powder (DRP) and ethylene vinyl acetate copolymer (EVA) were used as asphalt modifiers. The performance of composite modified asphalt with different VA content and EVA dosage was investigated. It was concluded that the high temperature performance of EVA-1 was superior to EVA-3, but the low temperature effect was average. The modified asphalt prepared with EVA-3 was better suited for cold weather, and the modified asphalt prepared with EVA-2 exhibited good performance in both high and low temperature plasticity, making it suitable for cold weather conditions. good low-temperature plasticity, can improve the physical properties of waste rubber modified asphalt, suitable for conventional asphalt pavement.

The massive amount of water-soluble urea used leads to nutrient loss and environmental pollution in both water and soil. The aim of this study was to develop a novel lignin-based slow-release envelope material that has essential nitrogen and sulfur elements for plants. After the amination reaction with a hydrolysate of yak hair keratin, the coating formulation was obtained by adding different loadings (2, 5, 8, 14 wt%) of aminated lignin (AL) to 5% polyvinyl alcohol (PVA) solution. These formulations were cast into films and characterized for their structure, thermal stability, and mechanical and physicochemical properties. The results showed that the PVA-AL (8%) formulation had good physical and chemical properties in terms of water absorption and mechanical properties, and it showed good degradation in soil with 51% weight loss after 45 days. It is suitable for use as a coating material for fertilizers. Through high-pressure spraying technology, enveloped urea particles with a PVA-AL (8%) solution were obtained, which showed good morphology and slow-release performance. Compared with urea, the highest urea release was only 96.4% after 30 days, conforming to Higuchi model, Ritger–Peppas model, and second-order dynamic model. The continuous nitrogen supply of PVA-AL coated urea to Brassica napus was verified by potting experiments. Therefore, the lignin-based composite can be used as a coating material to produce a new slow-release nitrogen fertilizer for sustainable crop production.

The loose and porous structure and abundant pores of biochar provide conditions for being a suitable fertilizer carrier. Biochar loaded with beneficial microorganisms will greatly promote plant growth and soil improvement. In this work, an environmentally friendly Paenibacillus mucilaginosus loaded biochar-based fertilizer (B@PM) with high nutrient content, good slow-release effect and increased biological activity was prepared. The released mechanism of P-K-Ca from B@PM and the synergistic effect on the soil nutrients and plant growth were also analyzed. The experimental results showed that the release behavior of P, K and Ca from B@PM was diffusive and dissolved, which conforms to the Power function and Parabolic diffusion models, respectively. The potting experiment showed that the root length (30.77%), leaf width (71.67%), and plant height (81.08%) of Chinese cabbage were enhanced after the application of B@PM, and the organic matter, available phosphorus, available potassium, and total calcium in the soil were also substantially enhanced. In addition, the abundance of the Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes in the in the rhizosphere soil was increased, as well as the activities of catalase (82.84%) and alkaline phosphatase (39.64%). The results of RDA analyses showed that B@PM increased the content of the environmental factors, such as OM, URE, EC, TCa, AK, CAT, AP and ALP, thus improving soil quality and plant length.

The recycling of waste tires avoids the environmental hazards of landfills and incineration, and its application in asphalt modification achieves resource sustainability. Currently, desulfurized rubber powder (DRP) is widely used as an asphalt modifier, mainly mixed with SBS, and fewer studies have been conducted on high-dose asphalt modification with ethylene vinyl acetate (EVA). In this paper, DR/EVA-composite-modified asphalt (DR/EVACMA) was prepared using 20% DRP and 4% EVA by adding four additives: furfural extract oil (FEO), a crosslinking agent (DCP), a vulcanizing agent (sulfur), and a silane coupling agent (KH-550). The aim was to study the effects of different additives on the physical properties, storage stability, and rheological properties of asphalt. First, conventional physical property measurements were carried out, and the data were analyzed using a polar analysis to determine the degree of influence of the four additives and the optimal ratios. Then, the rheological properties and fatigue resistance of DR/EVACMA were investigated through temperature scanning experiments, linear amplitude scanning (LAS) experiments, and multi-stress creep (MSCR) experiments. Finally, the reaction mechanism and microscopic properties were analyzed through infrared spectroscopy experiments (FTIR) and fluorescence microscopy (FM). The results showed that FEO had the greatest effect on asphalt characteristics. Compared to matrix asphalt and additive-free asphalt, DR/EVACMA has higher physical properties, fatigue resistance, and high temperature rheological properties due to its internal crosslinking structure. Its storage stability is also very good, with a difference of only 0.7 °C in the softening point.