Advanced Materials Research Vols. 261-263

Abstract: Reliability analysis is a useful and comprehensive approach for estimation of liquefaction potential in soil layers. The most commonly used methods in reliability analysis are first order second moment (FOSM) and Hasofer&Lind approaches. These methods are based on some simplified assumptions such as the use of a linear performance function or the numerical estimation which often lead to less accurate results. Monte Carlo simulation (MCS) approach is an alternative and more accurate method for reliability analysis and for evaluation of liquefaction potential in soil deposits. In this study, liquefaction potential is assessed using MCS approach followed by a case study in which an area prone to liquefaction is investigated. Results are compared with those obtained by other reliability methods. The efficiency of the MCS method is discussed in the paper.

Abstract: The TiO2 nanotube array thin films were fabricated on pure Ti plates by anodization process and annealed at 450oC, 500oC and 550oC for 30 minutes, respectively. The methylene blue (MB) degradation test was further conducted to evaluate the effects of annealing on the photocatalytic ability of TiO2 nanotube array. It was observed that better photocatalytic ability was found for the thin film annealed at 450oC, which was mainly the anatase phase. On the other hand, the anatase/rutile mixed phases were discovered on thin films annealed at 500oC and 550oC, respectively. In this work, the photocatalytic ability of TiO2 nanotube array with mixed anatase/rutile phases was not comparable to that reported in literature. It was suggested that the MB degradation ability was not only related to the crystallinity structure, but also strongly influenced by the surface characteristics of TiO2 nanotube array thin film.

Abstract: The circumference tensile force developed in the geotextile during filling the tube is the dominant factor to construct a safe dike. Based on the feature of flat tubes, a iterative procedure is programmed, with which the shape of the large size geotextile tube, as well as the relationship among the tube size, the pumping pressure, the unit weight of the slurry and the tensile stress developed in the geotextile during filing the tube can be determined. In the procedure, the inhomogeneousness induced by the soil grain sedimentation is also considered.

Abstract: In this paper, Portland cement was used as cementitious material and expanded perlite was used as insulation material. Fatty acid salt water repellent was also added to make this new thermal insulation, waterproof and light weight roof building material. It can be cast onto flat roof during construction or made into tiles and laid onto sloping roofs. This new roof building material had short construction period and can be completed in a one-time process. It may replace conventional construction method of applying insulation and waterproof materials separately.

Abstract: The reflectivity of ferrocene-doped carbon fiber-reinforced cement-matrix composites against the electromagnetic radiation was measured in the frequency range of 8-18 GHz for different carbon fiber contents of 0.4, 0.6, 0.89, 1.33, and 1.78 wt% by mass of cement. The ferrocene was doped in 0.89, 1.78, 3.56, 4.89, and 6.27 wt% by mass of cement respectively. The maximum reflectivity reached -4.0 dB when the fiber percentage was 0.89 and the ferrocene was 3.56. The microwave was attenuated by 64 % through reflection. The minimum reflectivity -7.5 dB occurred when the fiber percentage was 1.33 and the ferrocene percentage was 4.89. The microwave was attenuated by 67.5 % through absorption. Prior to the fiber percentage of 0.89 and the ferrocene percentage of 3.56, the reflectivity kept rising.

Abstract: This study proposes a new mixing process for producing commercially acceptable DSP mortar of high flowability, using commercial materials and water-bath curing at about 20°C. That is “three- speed mixing technics (TSMT)”. The properties of mortars mixed by TSMT and conventional technics (CT) are compared. At a water-to-binder ratio of 0.2, the compressive strength of the TSMT mixed DSP mortars was about 41.2% higher than that of the CT mixed DSP mortars of the same composition, the workability was also increased. The increase reason was investigated by the wedge-splitting section and Environmental SEM (ESEM) images. Additionally, for TSMT, the influence of mix-design parameters such as cement grade, the water/binder (w/b) ratio, the silicon fume/cement (sf/c) ration and the superplasticizer/cement (sp/c) ratio were studied.

Abstract: Due to the conventional flat plate solar collector has low efficient, it is necessary to make some improvements in the structure of conventional flat solar collector. This research improved the structure of conventional flat solar collector and conducted thermal performance testing for the improved structure which is serpentine heat pipe flat plate solar collector. The test results indicate that serpentine heat pipe flat plate solar collector has higher efficient than conventional solar collector. Thus, serpentine has better economic and environmental benefit than conventional solar collector.

Abstract: With special design and manufacture instruments, foot print of used truck tires under different combinations of vehicle load was studied in this paper. The load factor is studied in terms of wheel load and tire inflation pressure. Based on the experimental data, approach for quantitative expression of foot print is also researched. Thus, the behavior of tire-pavement contact can be quantitatively expressed The area of the tire’s footprint should be calculated with different equations varying with the kinds of pavement, and critical change point of the tire’s footprint shape should be decided with load factor varying with the kinds of pavements.

Abstract: Relative lower strength and poor creep resistance of wood-plastic composites (WPC) restrain their wider applications in building and automotive. A novel wood-polymer composite was prepared using Kraft fiber and unsaturated polyester (UPE), which had much higher strength and better creep resistances than that of traditional thermoplastic WPC. Effects of initiator on the mechanical properties and creep resistance of this novel composite were investigated by tensile evaluation, DMA, SEM and short-term creep test. Test results indicated that initiator level had important effects on mechanical properties and viscoelastic behaviors because of various crosslinking densities of UPE matrix and interface adhesions between Kraft fiber and UPE resin under various initiator levels. With initiator level increased from 0.3% to 1%, the tensile strength and interface adhesion increased at the beginning and then decreased, while the instantaneous strain and maximum strain in the creep test decreased gradually. As for hot molding at 125°C, initiator level shall be less more than 1% and be preferable to 0.5%-0.7%.

Abstract: For studying absorption/bearing integration of building materials, high-strength cement-based materials were prepared by using active fly ash, silica fume and quartz, etc. Electromagnetic parameters of the cement-based materials were measured through coaxial method, and then by means of these parameters, the reflectivity of electromagnetic waves of the cement-based materials were simulated under variable electromagnetic wave incident angle (θ), frequency (f) and thickness of the material(d).The reflectivity of electromagnetic waves with 8~18GHz frequency range vertically transmitting into the cement-based materials was obtained through far field radar scattered cross-section measurement, and was compared with simulated reflectance under the same incident conditions. The results show that the high-strength cement-based materials with imaginary part of dielectric constant can consume energy of the incident electromagnetic wave. Incident angle less than 15° has little effect on the reflectivity of the cement-based materials in 2~18GHz frequency range. While the thickness of the cement-based materials is 15mm or 25mm, simulation results of the reflectivity are in good agreement with measured ones. Measured absorption peak and -10dB bandwidth increase with the increasing of thickness of the cement-based materials with compressive strength of 120.7MPa. This suggests that the cement-based materials studied in this paper have the characteristics of absorption/bearing integration.