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Salt erosion is an important negative factor on the performance deterioration of asphalt-based materials. The basic properties of asphalt in salt erosion environments have been extensively studied; however, there is a certain lack of research on the rheological property of styrene–butadiene–styrene (SBS) modified asphalt under various salt erosion conditions. This study aims to identify the rheology deterioration of SBS modified asphalt under the action of salt freeze–thaw or saline immersion cycles through laboratory experiments. Rheological properties and creep recovery properties of SBS modified asphalt were tested based on the dynamic shear rheometer, and their rutting resistance capacity and fatigue cracking resistance were analyzed. Viscoelastic properties and low-temperature property of SBS modified asphalt were investigated by Burgers model, Christensen–Anderson–Marasteanu model and glass transition temperature. Results showed that the rutting capacity increased by an average of 34.5% and 39.7% after 21 times salt freeze–thaw and saline immersion cycles, respectively, while the fatigue cracking resistance decreased by 34.2% and 40.1%. Multi-stress creep recovery test manifested that both salt erosion modes had slight influence on the creep recovery property. However, the non-recoverable creep compliance at 3.2 kPa decreased by 37.5% and 32.3% after 21 times salt freeze–thaw and saline immersion cycles, respectively. Based on glass transition temperature, the low-temperature performance of asphalt decreased significantly after salt erosion. The rheological behavior and damage degree of asphalt were different for different salt erosion modes. The study may provide a theoretical basis for the construction and maintenance of asphalt pavement in salt-rich areas. [ABSTRACT FROM AUTHOR]

Adhesion is easily affected by moisture erosion, thus reducing pavement performance. SBS modified asphalt is widely used in road engineering due to its excellent performance. For analyzing the adhesion properties between SBS modified asphalt and aggregates under moisture damage, the macro-scale SBS modified asphalt-coated aggregates and micro-scale asphalt-aggregate adhesion models were prepared first. The moisture damage was applied to the coated aggregates and adhesion models subsequently. After that, the quantitative boiling tests and molecular dynamics (MD) simulations were carried out. Finally, the multi-scale adhesion results were analyzed using Pearson correlation analysis. The macro-scale results imply that as the degree of moisture damage increases, the stripping area of the asphalt-aggregate interface rises. The micro-scale results reveal the moisture damage mechanism that is the penetrated moisture into asphalt-aggregate interface disrupt the adhesion force by the action of hydrogen bonds and Van der Waals forces. The Pearson correlation coefficient is 0.996, which indicates that the multi-scale adhesion results present an extremely strong linear relationship. This research contributes to the analysis of moisture damage in asphalt pavements in pluvial as well as seasonal frozen regions, and also provides a reference for correlation analysis between the multi-scale results. [ABSTRACT FROM AUTHOR]

A novel highly efficient technology, intimate coupling photocatalysis and biodegradation (ICPB) for the treatment of refractory organic pollutants was introduced, and the carrier in ICPB based on sugarcane bagasse cellulose (SBC) was prepared. The SBC–TiO2 carrier produced was characterized using spectroscopy, microscopy, and diffraction techniques. The SEM image showed a rough and porous structure of the carrier, while as the EDS, XPS and XRD indicated that TiO2 was successfully added into the carrier, which retained its original crystal structure and provided the photocatalytic activity. The combined process of photocatalysis and biodegradation was much more efficient than a single process alone. The success in preparing bagasse cellulose based carrier in this study provided a significant contribution towards the development of a green and efficient technology system for the treatment of refractory organic matter. [ABSTRACT FROM AUTHOR]

Photocatalysis has emerged as a promising approach for treating environmental pollution. In this study, TiO2/sponge composites with good photocatalytic activity in visible light were prepared via a simple and efficient low-temperature process and applied to the degradation of 2,4,6-trichlorophenol (2,4,6-TCP) present in papermaking wastewater. The process conditions for preparing TiO2/sponge composites were optimized by varying the TiO2 dosage, cellulose dosage, and surfactant concentration. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) results showed that TiO2 successfully adhered to the sponge surface and that the composites achieved a good recycling effect. Degradation occurred under visible light, and a degradation rate of 81% for 2,4,6-TCP with initial concentration of 20 mg/L was achieved in 4 h. The fragments were analyzed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS), which revealed the formation of 2-hydroxyvaleric acid (2-HVA) as a degradation product; a possible degradation mechanism is proposed to interpret these findings. Visible-light photocatalysis shows high potential for the rapid and environmentally friendly destruction of organic pollutants in papermaking wastewater. [ABSTRACT FROM AUTHOR]