Advanced Materials Research Vols. 374-377

Abstract: A series of foam concrete with different content of fly ash or red mud were experimentally investigated in this study. The results indicated that the water-solids ratio of optimized material proportion and curing conditions were 0.5, and the compressive strength and density of the concrete compressive would fall with the addition of fly ash or red mud.

Abstract: Zinc ions were incorporated into the holes of diatomite and the antibacterial effects of the zinc diatomite was evaluated by plate counting of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). When 1wt% of the antibacterial zinc diatomite was incorporated into paint, almost all the S. aureus and E. coli on the surface were killed. This study revealed that the antibacterial capability of zinc diatomite can kill almost all of the bacteria in the diatomite holes and the surface. The preparation and microstructure of the antibacterial zinc diatomite were also studied.

Abstract: Organic lightweight aggregate concrete (OAC) is produced by replacing normal aggregate with organic aggregate in concrete or mortar either partially or fully, depending on the requirements of the strength and density. The study aims to investigate the compressive strength of OAC containing virgin EPS beads, recycled EPS granules and rubber granules with diameter 3-5 mm, and the influence of cement matrix on compressive strength of OAC. The results show that compressive strength of OAC decreases as organic aggregate content increases; furthermore, the decreasing rate of the strength is slowing down. The dimensionless compress strength-density relationship of EPS lightweight aggregate concrete (PAC) containing virgin EPS, recycled EPS and different cement matrix has uniform law. It can be modeled as σ^*_pl /σ_s=0.916(ρ^*/ρ_s)^3.04. The experimental compressive strength of ultra-lightweight EPS concrete with density lower than 900 kg/m³ is much higher than the value calculated by Gibson formula. The larger the relative density is, the greater the difference between the two is. The dimensionless compressive strength-density relationship of rubcrete can be modeled as σ^*_pl /σ_s=0.956(ρ^*/ρ_s)^8.66. The compressive strength of rubcrete, compared with PAC, is more sensitive to the relative density.

Abstract: The comparison experiments are carried out at different silica fume dosage between the silica fume with pre-treatment and the silica fume without pre-treatment. The results show that the pre-treatment of silica fume improved the strength greatly and the silica fume dosage corresponding to the strength peak somewhat moved forward from 0.20 for the cement-based materials with pre-treatment of silica fume to 0.21 for the cement-based materials without pre-treatment of silica fume. The particles distribution experiment results indicate that after the pre-treatment of silica fume, the average particle diameter of silica fume reduced from 2.865μｍto 0.151μｍ. Based on Aim-Goff model, it is concluded that the increase in the compressive strength and flextural strength of cement-based materials with pre-treatment of silica fume, are attributed to the dispersion of silica fume agglomeration and the increase in the packing density of the cement-based materials.

Abstract: La _0.67 Sr _0.33 MnO ₃ particles with different particle size have been prepared by sol-gel method. The structure, magnetization and microwave absorption properties have been investigated. The results show that the particle size can be controlled by sinter temperature. The peaks of the maximum reflection loss (RL) move to higher frequency regions with increasing particle size. The value of the maximum RL is -32 dB at 10.2GHz with a particle size of 58.5nm. The bandwidth with a RL exceeding -8dB reached 1.6GHz in the whole measured frequency range, suggesting that La _0.67 Sr _0.33 MnO ₃ particles are promising for application as a wideband and strong absorption building microwave absorber.

Abstract: The living quality of the Taiwanese citizens keeps rising; the improvement of floor impact sound has being carried out into practical project gradually. The void slab, used to be used in huge span building, is very common in housing building. From reference, the void slab represents the one of the latest architectural facilities, which focuses on the noise improvement for the living quality, by its characteristics of rigidity and lightweight. In order to select an appropriate floor covering material, the experimental investigation based on the standard ISO 140-7 and 140-8 should be carried out to experiment the performance of the bare void slab and the covering materials over the slab for discussing the possibility of material application on the void slab. Therefore, in this study, the noise insulating performance of the void slab through the field experiments in the practical condominium-type housing projects will be tested, and the floor impact sound performance of the selected sample of covering materials (teak wood and carpet) applied on the existing void slab will also be shown in this paper. The results show that the void slab presents good effective performance for heavy floor impact sound, but the void slab should be applied with covering materials to demonstrate efficient improvement toward the light floor impact sound, and the performance varies from materials. The researchers expect that the database could provide designers and constructors the reference of the floor covering materials related to the floor impact sound insulation and reduce the time and the costs issue.

Abstract: This study is going to use the Grey relational analysis (GRA) to analyze the Test of the van Hiele levels of geometrical reasoning. The current results of this study is not only identify the easiest and the most difficult questions for students, but also displays that the proposed GRA provides a novel approach in handling educational test.

Abstract: Sugar mud has been analyzed to prepare porous ceramics with clay, and the principal chemical component of sugar mud was tested to be CaCO3. The optimal ratio of sugar mud and clay came out to be 1:2. The porous ceramics were sintered at temperatures of 1 000°C for 1.5h, whose major crystalline phases were found to be Porzite, Anorthite and Cristobalite, have showed good performances. The final products with pore size ranging from 1 to 10μm, a porosity of 26.38%, a water-absorption of 17.30%, and mechanical strength of 22～26 MPa could be applied in the area of permeable porous ceramics.

Abstract: Rigid polyurethane foams were excellent thermal insulation materials with widely used, which was highly flammable at the same time. In order to obtain safe application, flame retarded polyurethane foams were needed. In this paper, series flame retarded rigid polyurethane foams were prepared with loading different flame retardants such as ammonium polyphosphate, expandable graphite, red phosphorus, Tri (2-chloroethyl) phosphate and dimethyl methylphosphonate. The effects of flame retardants on the foaming-process and flame retardant property of the rigid polyurethane foams were investigated by otary viscometer and limiting oxygen index. The results showed that the combination of solid and liquid flame retardants was necessary to improve the flame retardant and different flame retardants played synergistic roles in rigid polyurethane foams. The limiting oxygen indexes of the foams could be up to 30wt% and 29.6% with 25wt% solid flame retardants and 10wt% liquid retardants, respectively.

Abstract: This paper investigates the corrosion behavior of galvanized steel in simulated rain using electrochemical method and surface analysis. The results indicate that the open circuit potential (OCP) for galvanized steel in simulated rain tends to be stable at -1.122V (SCE). With the increase of pH value, the corrosion current density (Icorr) for galvanized steel in simulated rain decreases initially and increases afterwards. Contrary to Icorr, the linear polarization resistance (Rp) for galvanized steel in simulated rain increases first and then declines. When pH value equals to 8.00, Icorr arrives at the minimum value whereas Rp reaches to its maximum. The findings also demonstrate that serious corrosion occurred on the surface of galvanized steel after immersing in simulated rain, besides, local corrosion was also observed, and the corrosion products are mainly zinc carbonate.