Advanced Materials Research Vols. 150-151

Abstract: Polypropylene and wood flour were used as raw materials,maleic anhydride grafted polypropylene(MAPP) as compatibilizing agent, wood-plastic composite(WPC) was prepared by compression molding process. The effects of the content of MAPP on the mechanical and thermal properties of WPC were investigated. The results show that, with the increase of the content of MAPP, both the tensile and flexural strengths of WPC will increase, and the impact strength of WPC increases first, then decreases, and the impact strength reaches the maximum of 1.18kJ/m2 when the content of MAPP is 4%,which is 76.7% increased from that of the composite without MAPP. Each composite has an obvious heat-absorption peak when melted during 140-170 and the melting enthalpy of WPC increases with the content of MAPP, the melting procedures of all the composites are quite similar with one another. Application of MAPP can improve the thermal stability of WPC

Abstract: By means of computer simulation for the flow field, the condition of swirling cavitation formation and the shape of cavitation distribution were analyzed with CFD software. The accuracy of simulation results and the validity of wastewater treatment device were verified according to the testing results of device’s working parameters and degradation for Rhodamine B. The criterion to judge cavitation formation or degradation efficiency has been established. The industrialized enlargement for mini wastewater treatment device has been analyzed by means of simulation. It is useful to establish industrial application foundation of this kind of wastewater treatment device.

Abstract: Because the SRC (steel reinforced concrete) structures fully combine the advantages of two materials i.e. steel and concrete they had been widely used in high-rise buildings. Completely study the moment-curvature relation of this kind of member is essential to a nonlinear analysis of this type of structures. The fiber model method based on the section discretion directly reflect the restoring characteristics of the member though the stress-strain relationship of steel and concrete. It can be applied to analyze section with any configuration. In this paper, the hysteretic moment-curvature relation of SRC column is analyzed by coding and verified by available test result. And finally several factors influenced on the M-Фrelation is discussed.

Abstract: What kind of role do the reactive aluminous has played during early hydration process of metakaolin-cement paste is investigated in present study. Therefore, metakaolin(MK) samples containing 45.94%, 22.86%, 0% reactive aluminous are prepared, respectively. In addition, X-ray Diffraction (XRD) analysis is employed to identify the crystalline phases of all specimens. The amount of acid-insoluble residue (AIR) of all specimens is used to evaluate the unreacted materials. The results obtained indicate that reactive aluminous can promote development of the early period strength significantly. Reactive silica and reactive aluminous reaction velocity was very slow during the first three days, then increased. The reaction velocity of reactive aluminous was faster than reactive silica between the first day and third day, but it shows an opposite result between the third day and seventh day.

Abstract: Spalling on loess slope threats the safety of highway and destroys its ecological environment. This paper proposes treatment materials for medium thickness spalling on loess slope. This materials treat the spalling in loess slope by the Reinforced function of straw, Bonding effect of silt, retain soil moisture and insulation effect of straw silt nutrition materials of silt mixed with straw, and fixation effect of T-shaped spiral steel anchor net, so that the treated slope can be protected and greened. It can effectively reinforce the loess slope, and prevent it from spalling.

Abstract: The objective of this research was to investigate thermal stability and dynamic mechanical behavior of nano-SiO2/phenol formaldehyde resin (PF) nanocomposites with various nano-SiO2 at 2 wt% loading content. The nano-SiO2/PF nanocomposites were fabricated by two-roll compounding and compression molding technology. The storage modulus (E′) at the starting point of 50 was increased by adding various nano-SiO2 into PF matrix. The E′ of the nanocomposite with only 2 wt% of SiO2 synthesized under ultrasonic irradiation (U-SiO2) was 2 times higher than that of the control PF. Thermal expansion and the coefficient of thermal expansion of nano-SiO2 loaded nanocomposites were lower than that of the control PF in the range of 100–200 and 200–250 . Thermogravimetric analysis demonstrated that the thermal stability of nanocomposites was evidently enhanced. In comparison, U-SiO2 reinforced nanocomposites showed higher thermal properties than those reinforced by mesoporous silica (SBA-15) and SiO2 synthesized by stirring (S-SiO2).

Abstract: An asphalt modified by epoxy resin and rubber has the following improved properties: the softening point is 70 , elastic recovery rate is 80%, and kinematic viscosity at 175 is 2879.1mm2 /s. In order to solve the early curing in the process of mixing, storage and transportation, methyl hexahydrophthalic anhydride(MHHPA) was used as the curing agent. A reflective cracking caused by traffic load simulation test was established with the objective to compare the propagation speed of reflective crack of three different structure asphalt mixture samples. The results showed that the sample with epoxy resin and rubber used as stress-absorbing layer can obviously delay reflective cracking, improve the pavement performance and prolong the road life. Furthermore, the results of Marshall test, immersion Marshall test and Rutting test were consistent with the results of the reflective crack simulation test.

Abstract: The behavior of confined concrete is highly dependent on the confinement type of transverse reinforcement, spiral hoops are generally believed to have better confined effect in concrete than rectangular hoops. It is verified through experiments and the oretical calculations that multi-spiral confined concrete columns have better mechanical properties than single spiral columns, the multi-spiral significantly increase the column’s strength, plasticity, ductility and anti-seismic capability. Based on the three-direction stress law of confined concrete, the load carrying capacity of the rectangular cross section concrete column with multi-spiral is analysed in this paper, and the calculated equation of the load carrying capacity is proposed, which provide a theory and calculation basis for multi-spiral confined concrete column design and research.

Abstract: Nowadays, nanocomposite tool materials are very important in engineering field for their excellent mechanical properties and stability under high temperature and have a good foreground in the coming years. However, there are lots of puzzles to be discussed in the materials design theory and the fabrication processing due to the difference between the traditional materials and the nanocomposite. In this paper, a new tool materials design method is proposed based on the interface strengthening theory. The sintering temperature and the soaking time are optimized based on the interface strengthening theory and the relative density of the tool materials is also discussed. The wild phase content can be fixed by calculating the debonding interface rate and the strength requirement of the tool materials. Meanwhile, a series of experiments are carried out to fabricate and optimized the nanocomposite tool materials under the guider of the interface strengthening theory. Results show that experimental data is in accordance well with the calculation and the interface strengthening theory.

Abstract: Aiming at a novel adsorption agent material, ACF/CNT composites were fabricated by growing carbon nanotubes (CNTs) on the surface of activated carbon fibers (ACFs) with chemical vapor deposition (CVD) method. The characteristics of ACF/CNT composites were investigated by SEM. The variables effects on CNTs size, uniformity and density were evaluated. Three major variables were optimized as the concentration of catalyst precursor 0.07 mol/L, pyrolysis temperature 750 and pyrolysis time 40 min respectively. The results show that CNTs are uniform distribution on the surface of ACFs and the diameter of CNTs is in the range of 30-60 nm and BET specific surface area is 65.39 m2/g. ACF/CNT composites are looked forward to be a promising materials for wastewater and flue gas treatment and hydrogen storage for proton exchange membrane fuel cells.