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Asphalt pavements often experience damage from freeze–thaw cycles in seasonal frozen regions, and asphalt–aggregate adhesion is essential to asphalt mixtures' ability to withstand freeze–thaw damage. To quantitatively investigate the effect of asphalt–aggregate adhesion on mechanical performance of asphalt mixtures under freeze–thaw cycles, in this study, loose asphalt stones were prepared with coarse aggregates, and the quantitative boiling test was performed to evaluate the asphalt–aggregate adhesion property under freeze–thaw cycles at first; subsequently, the high-temperature creep and low-temperature splitting test were adopted with the stone matrix asphalt (SMA) to evaluate the mechanical performance under freeze–thaw cycles; finally, the gray relation analysis (GRA) method was used to analyze the relationship between the asphalt–aggregate adhesion property and mechanical performance. The results suggested that the asphalt–aggregate adhesion property decreased rapidly as the freeze–thaw cycle increased. The high-temperature viscous strain increased 346.13%, and the low-temperature strain energy decreased 14.34% after 21 freeze–thaw cycles. Through the GRA method, it was found that asphalt–aggregate adhesion properties with 4.75 and 9.5 mm sieve-size aggregates had a greater impact on the elastic and viscous properties of SMA, respectively. This study contributes to the design of SMA in seasonal frozen regions and provides a reference to study the damage mechanism of other types of asphalt mixtures in seasonal frozen regions. [ABSTRACT FROM AUTHOR]

The pineapple peel cellulose(PPC) was used as raw material to dissolve in an alkali/urea solution with incorporation of bentonite, then further chemically cross-linked and in-situ embedded with magnetic Fe3O4 to form composite hydrogels. The structure and dye adsorption properties of hydrogels were studied. The results confirmed the successful intercalation of bentonite and Fe3O4 in the hydrogels. The bentonite effectively improved the cross-linked porous network structure, thermal stability and swelling properties of the hydrogel. The bentonite also enhanced the methylene blue adsorption performance of the hydrogels, showing an increased saturated adsorption capacity from 28. 09 mg/g to 55. 87 mg/g. The adsorption process conformed to the pseudo-second-order kinetic model and Langmuir model, belonging to chemical adsorption and monolayer adsorption. [ABSTRACT FROM AUTHOR]

For economical and convenient construction of road pavement, the prefabricated road base is used in pavement engineering as a new construction technique. The same as the other prefabricated structure, the joints of prefabricated road base blocks need a caulking material to fulfill and connect, and cement mortar is selected because of its superb properties in mechanics and workability. Aimed to evaluate the cement mortar with different additives, such as redispersion emulsoid powder and defoamer to meet the needs of prefabricated road base, three experimental groups of cement mortar are compared with the control group through mechanical properties tests, durability tests, and fatigue tests in this paper. By analyzing the results of these laboratory experimental tests, it can be found that the addition of redispersion emulsoid powder in the cement mortar can improve the deformability and the ability of frost resistance, and the addition of defoamer can improve the mechanical properties but decrease the frost resistance. And the cement mortar with redispersion emulsoid powder and defoamer obtains an excellent fatigue performance. [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]

Intimate coupling of photocatalysis and biodegradation (ICPB) has shown promise in removing unwanted organic compounds from water. In this study, bagasse cellulose titanium dioxide composite carrier (SBC-TiO 2 ) was prepared by low-temperature foaming methods. The optimum preparation conditions, material characterization and photocatalytic performance of the composite carrier were then explored. By conducting a single factor test, we found that bagasse cellulose with a mass fraction of 4%, a polyvinyl alcohol solution (PVA) with a mass fraction of 5% and 20 g of a pore-forming agent were optimum conditions for the composite carrier. Under these conditions, good wet density, porosity, water absorption and retention could be realized. Scanning electron microscopy (SEM) results showed that the composite carrier exhibited good biologic adhesion. X-ray spectroscopy (EDS) results confirmed the successful incorporation of nano-TiO 2 dioxide into the composite carrier. When the mass concentration of methylene blue (MB) was 10 mg L -1 at 200 mL, 2 g of the composite carrier was added and the initial pH value of the reaction was maintained at 6, the catalytic effect was best under these conditions and the degradation rate reached 78.91% after 6 h. The method of preparing the composite carrier can aid in the degradation of hard-to-degrade organic compounds via ICPB. These results provide a solid platform for technical research and development in the field of wastewater treatment.