Advanced Materials Research Vols. 399-401

Abstract: In this paper, different polymer dosage in case of mechanical properties of fly ash slurry, through testing studies have shown that low-dosage strength of fly ash slurry has increased the role of high-dosage resulting in lower intensity, but the overall pressure off than reduced, improving the flexibility of fly ash cement, is it has a certain flexibility.

Abstract: Real-time monitoring of concrete of rebar in concrete is studied in this paper, electrochemical method is the simplest method, monitoring of corrosion of rebar in concrete. This method is simple in an ever-changing environment, can reflect the corrosion of rebar in a long time.It not only can detect the rebar corrosion rate, also can test the long-term corrosion quantity. With the help of the polarization resistance measured regularly, the quantity of rebar corrosion can be estimated in a certain time.

Abstract: Orthorhombic Nb₂WO₈ was synthesized by solid state reaction in Nb₂O₅-WO₃ system. Heterojunction photocatalyst Nb₂WO₈/ZnO was prepared by ball milling. The structural and optical properties of the photocatalyst were characterized by X-ray powder diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, and fluorescence emission spectroscopy.The photocatalytic activity was evaluated by photocatalytic oxidation of rhodamine B and reduction of Cr⁶⁺. The results showed that the photocatalytic activity of the Nb₂WO₈/ZnO was higher than that of ZnO. When the amount of doped Nb2WO8 was 10 wt.% and the sample was ball milled for 9 h, the Nb₂WO₈/ZnO showed the optimal photocatalytic activity. Effect of ball milling time on the photocatalytic activity was also investigated. The mechanisms of the increase in the photocatalytic activity were discussed by the valence band principle.

Abstract: Alkali activated slag cement and concrete are high strength, rapid hardening, low heat of hydration, good durability and so on. Whereas, too high viscosity and bad workability of the fresh mixture is the crux of the matter to embarrass application of alkali-activated slag cement and concrete. Development of special superplasticizer for alkali activated slag cement and concrete is a worth exploring way to solve the problem, and the study on the surface tension of simulated solutions of alkali activated slag cement system is one of the basic researches about the special superplasticizer. In this paper, the surface tension of surfactant-alkali-water was studied by Wilhelmy method. The results showed, first, water-glass had the best efficacity of several alkali activators, when the modulus of water-glass was 1.5 and dosage of water-glass by Na2O was 8%, the surface tension was reduced by 33 mN/m and reduced to 39.9mN/m; second, [CH₃(CH₂)₉]₂N(CH₃)₂Cl had the best efficacity of several surfactants, when the concentration of [CH₃(CH₂)₉]₂N(CH₃)₂Cl was 50g/L, the surface tension was reduced by 35.3 mN/m and reduced to 32.5 mN/m; finally, the effect of surfactant and alkali together on the surface tension of water was complex, surfactants had hardly effective in water glass.

Abstract: Nowadays, one of the most essential environmental issues around the world is to deal with the scrap tire problem. Tires that are used, rejected or unwanted are classified as scrap tires and need to be managed responsibly. In this paper, the scrap tires were shredded into pieces and used to mix with normal weight concrete. Extensive laboratory tests were carried out and the focus of this paper was to characterize the mechanical and permeability properties of concrete containing scrap tires. The main parameters studied were chipped tire content and size. The results showed that the scrap-tire chips without adding special bonding agents apparently showed an even distribution in the mortar and concrete matrix. The elastic modulus, compressive and tensile strengths of scrap tire concrete in general were found lower than that of the control concrete and the differences became significant when the content and size of chipped tires in the mix were increased. Besides, the coefficients of water permeability of concrete were found to increase with increase of chipped tires in the mix.

Abstract: The matrixes for the controlled release system have been prepared by blending polyvinyl alcohol (PVA) and the reworked granules of recycled polypropylene (PP) with EVA as a compatibilizer on a single screw extruder. The changes of microphase (crystalline) structure and macrophase structure of the PP/PVA blends were investigated by the differential scanning calorimetry (DSC) and scanning electron microscope (SEM). The controlled release formulation (CRF) of Bensulfuron-methyl based on the blends was prepared by means of melt-extrusion, and the release behaviors of bioactive agents were investigated in the different pH buffers with UV spectrophotometer. To a certain extent, the PP/PVA blends showed the components compatibility. The results also showed that there was gradual decrease in the crystallinity of PP with increasing PVA content. The bensulfuron-methyl CRFs exhibited the obviously controlled-release function. The release rate of bensulfuron-methyl was found to be faster in the neutral media than in acidic or basic media. The pesticide CRFs could have an important potential in reducing inefficient use and impact of pesticides in the environment. Moreover, a novel method was provided for recycling and utilizing PP wasters.

Abstract: With a view to research cottonseed protein in application of material field, cottonseed protein was used with glutaraldehyde to take place a crosslinking reaction, montmorillnite in nanometer level was also added to the reaction system, to manufacture a kind of cottonseed protein plastic with high mechanical properties and low water absorption. Influences of molding temperature, content of glutaraldehyde and montmorillnite to mechanical properties and water absorption were studied. Plastic samples were analyzed by X-ray diffraction and SEM surface topography. When the mass content of glutaraldehyde and montmorillnite to cottonseed protein is 30%, 6% respectively, the tensile strength and water absorption of cottonseed protein plastic is 19.1MPa, 27.8% respectively.

Abstract: Using arc-length method, the progress of solving nonlinear function is discussed for designing new numerical analyzing tool, and the frame of programming based on nonlinear method is compiled. The results from completely restricted modeling show convex deformation and the damage on oblique section. And with the concrete elastic-plastic constitutive used in numerical simulation including add uninstall, typical engineering examples inspect reliability of the elastic-plastic numerical analysis program. This provides the basis and guidance for the future of the specific program design.

Abstract: Nanostructured AgI/TiO₂ photocatalysts exhibit highly efficient visible light photocatalytic activity. Though there have been extensive investigations on AgI/TiO₂ photocatalysts, study on their stablity is still very limited. So in this paper, such a study is designed and conducted. AgI/TiO₂ nanostructured photocatalysts were prepared and separately immersed in HCl solutions, DI water and NaOH solutions with pH value of 0, 4, 7, 10 and 14, respectively. X-ray diffraction and diffusive reflectance UV-vis spectroscopy analyses reveal that the immersion in acidic solutions led to the formation of AgCl and a blue shifting to 450nm for the absorption edge of AgI/TiO₂, while the alkaline treatment had no significant effect on the composite structure of AgI/TiO₂ or on the UV-vis absorption edge. Photocatalytic tests show that immersion in acidic solutions had more significant influence on AgI/TiO₂ photocatalytic degradation of methyl orange (MO). At pH = 4, photocatalytic efficiency was dropped nearly 30%. At pH = 10, no significant change was observed. AgI/TiO₂ nanostructured photocatalysts have thus been found to display a higher stability in alkaline solutions than in acidic solutions.

Abstract: The influence of stone dust content on chloride diffusion coefficient in C30, C40 and C50 grade concretes were investigated by means of the natural immersion test, XRD test, MIP test, SEM and TGA test, respectively. The experimental results showed that the chloride diffusion coefficient in C30 grade concretes decreased with increasing the stone dust content, but it decreased first and then increased with increasing the stone dust content in C40 and C50 grade concretes. The hydration degree for cementitious and compressive strength for concrete was slightly promoted by using stone dust replacing cementitious at a low level. For C30 grade concretes, the porosity decreased with increasing the stone dust content in fine aggregate, but for C40 and C50 grade concretes, the total porosity decreased first then increased with increasing the stone dust content. And the concrete pore structure was the main factor that influences the changes of chloride diffusion coefficient in concrete.