Advanced Materials Research Vol. 905

Abstract: Thin metallic shells have long been adopted as major structural components in weight-sensitive applications, especially in marine engineering. Imperfection sensitive buckling is a critical design factor when these structures are loaded in compression. Traditional experimental design method depends on deriving lower bounds to the scatter of large sets of test results. This paper aims to present an analytical approach, the so-called reduced stiffness method (RSM) to the lower-bound buckling of thin-metallic shells. The validity of the RSM for the prediction of the safe lower bounds to the buckling of thin shells is verified through carefully controlled finite element analysis and the comparative studies confirm the reliability of the RSM.

Abstract: The global development and current trends in social attitude are resulting in an increase in the amount of waste generated by society, the treatment and disposal of which are becoming a serious problem. Therefore, waste management is one of the most important aspects in ensuring sustainable development in todays world. Some of the industrial by-products, such as pulverised-fuel ash (PFA), ground granulated blast-furnace slag (GGBS) and microsilica (MS) can be used in concrete to improve its properties. In this paper the influence of various by-products on the physical properties of concrete is reviewed.

Abstract: Shrinkage cracks in cement-stabilized macadam base are seriously influences performance of asphalt surface. Setting about cracking mechanism for transverse shrinkage crack for cement-stabilized macadam base, combined with theoretic analysis and outdoor test method, we shall study for the method for reduction of base crack. Samples with different dosage of cement were selected from test road, as well as select out corresponding parameter to make calculation. Analysis for finite element and outdoor test result indicated that suitable reduction for cement dosage and improvement for construction workmanship shall effectively reduce in crack creation for cement-stabilized macadam base.

Abstract: The paper addresses a generalized perturbation method for the uncertainty analysis of concrete structures subject to reinforcement corrosion. The initiation phase is modelled by the well known Ficks 2^nd law of diffusion. Deterioration models derived from experimental studies and a non-linear finite element (FE) model are used to simulate the structural behaviour of beams from the serviceability to the ultimate conditions. The time of corrosion initiation and the failure load are expressed by a Taylor series expansion about the origin of the space of independent standard normal random variables.

Abstract: This research is aimed at investigating the effect of elevated temperature, curing duration and curing methods on the strength recovery of lightweight concrete. Concrete specimens were subjected to elevated temperatures ranging from 300 to 600°C in a controlled heating environment. The specimens were subjected to three types of curing conditions: continuous water curing at 27°C, curing in a relative humidity of 95% at 27°C and curing in water at 60°C for three days and then curing in water at 27°C. The curing duration ranged from 7 to 56 days. The results indicated that the re-curing of concrete for the recovery of compressive strength is most effective in the temperature range from 300 to 500°C. For temperatures outside the range of 300 to 500°C, re-curing was either not effective or had limited application.

Abstract: This study aims to address the question of accessibility on sidewalks in accordance with Rule 9050 of the Brazilian Association of Technical Standards (ABNT NBR 9050:2004) and analyze the feasibility of using alternative materials (steel fibers, construction waste and rubber) to produce Interlocking tactile concrete paver. It was performed an experimental dosage of concrete with 04 specimens: reference, with steel fiber, with rubber and with steel fiber and construction waste. The pavers molded with conventional concrete and with the addition of alternative materials were tested as for compression strength and water absorption and the results were satisfactory, meeting the specifications of the Brazilian standard.

Abstract: The microstructure of asphalt materials on photocatalytic performance was studied in this work. Firstly, asphalt composite coatings with highly ordered honeycomb microstructures were fabricated by a bottom-up approach through adjusting the solution concentration and the content of polystyrene (PS) additive. Further incorporation of titanium dioxide (TiO₂) nanoparticles endows the porous coatings with photocatalytic functionality. SEM images demonstrate that TiO₂ nanoparticles disperse and decorate on the pore walls of coating. In comparison to the compact coatings prepared by traditional method, the obtained honeycomb microstructured asphalt/PS/TiO₂ coatings possess an enhanced and sustainable efficiency of removing NO_x. Specifically, when introducing porous microstructures to the coating, the NO_x reduction efficiency is 16% higher than that of traditional compact sample and shows no attenuation in continuous use.

Abstract: In this study, seven types of first-order and one-variable grey differential equation model (abbreviated as GM (1, 1) model) were used to predict the hardness of four groundwater monitoring stations in Kaohsiung City of Taiwan. The mean absolute percentage error (MAPE) was used to evaluate the predicting performance. The results indicated the minimum MAPE of 4.71 %, 3.15 %, 2.66 %, and 16.63 % could be achieved when predicting hardness of Fonsi, Datung, Shaukang, and Chihsien stations, respectively. According to the results, it revealed that GM (1, 1) was an efficiently early warning tool for providing groundwater quality information to the competent authority.

Abstract: Carbonation is a common influence of cement-based material. And the accelerated carbonation is used in material property modify. With the reaction in the material when carbonating, the carbon dioxide will be solidifying in the material, in the shape of precipitation of calcium carbonate filled the pore. But the ability of the carbon absorbing is unknown, in this paper, some cement-based building materials are took in test, including the aerated brick, cement tile, concrete, and cement mortar. In according to the results, it has found that the carbon absorbing ability is different, and with the carbon absorbing, the strength also increasing. The aerated brick is greatest and the condition of temperature, pressure and reaction time is lowest, which give a reference on the way of the greenhouse gas transform and reduced.

Abstract: Water is present in many routine activities performed by man. However, these activities have been generating wastewater who require treatment before being cast into water bodies. The constructed wetlands are alternative wastewater treatment low cost of construction and maintenance, therefore do not require electricity and chemical application. Perform well in the removal of polluting effluent load and have advantages of being aesthetically pleasing due to the presence of aquatic plants. This work presents a proposal to mount a wetland constructed for the post-treatment of domestic wastewater in laboratory scale subsurface flow and intermittent, macrophyte was used mini papyrus (Cyperus isocladus) and substate fragments ceramic tiles.