Advanced Materials Research Vol. 905

Abstract: Chemical, physical, morphological, and mineralogical analysis of sewage sludge originating from a waste water treatment plant in Patras, Greece, is presented in the paper. The sewage sludge is firstly dried at 70°C, then oven-burned at 700°C for two hours and milled. The thermally treated material is analyzed using XRF and XRD, the particle size distribution is determined by a laser diffraction method. A potential use of sewage sludge in blended cements is investigated on the basis of the measurement of mechanical and basic physical properties of pastes containing the sludge in an amount of up to 60% of the mass of cement. Experimental results show that the thermal treatment of pre-dried sewage sludge and its grinding provides a material that can be successfully applied as a partial replacement of Portland cement. At a production of blended cements for high strength concrete, an up to 20% cement replacement level can be recommended.

Abstract: The present study examined the in-place strength of high-strength concrete based on the relative strength-maturity relationship. The measured strength gain of high-strength concrete was compared with the predictions obtained from the modified maturity function to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. This study demonstrates that the compressive strength gain of concrete cured at the reference temperature (20°C) for an early age of 3 days is little affected by the subsequent curing temperature histories.

Abstract: The purpose of this study is to assess environmental friendliness of passive apartment house based on major building materials in Korea. To accomplish this, stage-wise quantity information of life cycle and energy consumption data were established on major materials through theoretical consideration on life cycle assessment. In addition, basic unit database from Korean LCI DB was utilized to assess and analyze characterization value of global warming assessment. As a result, the value of global warming was smaller in passive apartment house in comparison to general apartment house. As the effect of building materials in construction stage was analyzed to be greater than the effect of energy consumption in operation stage, development of diverse building materials taking environmental impact into account is deemed necessary.

Abstract: Along the process of setting and hardening in concrete, the temperature profile shows gradually a nonlinear distribution due to the development of hydration heat of cement. More specifically, at early ages of concrete structures, this nonlinear distribution has a large influence on the crack evolution. As a result, to obtain the exact temperature history, it is necessary to examine thermal properties of the concrete. In this study, the convective heat transfer coefficient, which presents heat transfer between concrete surface and air ambient, was experimentally investigated with test variables such as velocity of wind, type of form, and water-cement ratio.

Abstract: Porous sedimentary rocks have been popular structural and artistic materials in many European countries for many centuries. These rocks are characterized by more or less porous structure and their mechanical properties are in close relationship with the pore system. The durability of porous rocks is to considerable extent controlled by these properties. The paper deals with pore system characteristics of selected porous sedimentary rocks found in Czech Republic. The dependences of compressive and bending strength on porosity of Czech sandstones were found in form of simple exponential functions.

Abstract: A possible use of waste ceramic powder as a partial replacement of Portland cement in blended binders is studied. For the ceramic powder, originating from the contemporary hollow bricks production, the measurement of chemical composition is done using XRF and XRD analysis. The particle size distribution of ceramics and cement is accessed on the laser diffraction principle. The blended binders containing ceramic powder in an amount of 8, 16, 24, 32, and 40% of mass of cement are used for the preparation of cement pastes which are then characterized using the measurement of basic physical properties and mechanical properties. Experimental results show that an application of 16% waste ceramics in the blended binder provides sufficient mechanical properties of the paste. This makes good prerequisites for future research that will be focused on the development of new types of cement-based composites with incorporated ceramic waste powder.

Abstract: The CEB-FIP equations generally underestimate the shrinkage strains of heavyweight concrete, showing a more notable trend with the increase in ages and equivalent porosities of aggregate. This study formulated the shrinkage behavior of heavyweight magnetite concrete as an expanded version of GL 2000 model by introducing the parameter of an equivalent porosity of aggregates. The proposed models gave significantly more accurate predictions than CEB-FIP equations even at long-term ages.

Abstract: In the present study, the thermongravimetric analysis (TGA) of laboratory hardwood and softwood particleboard was studied. The TGA showed that both hardwood and softwood have similar thermal behaviour at the same peak temperature. However, softwood is concluded to have higher fire retardancy as more char formation happened in softwood. A further study was carried out to compare the thermal behaviour of laboratory manufactured boards with the commercial grade boards. Superior thermal stability of commercial particleboard had confirmed its effective crosslinking and wood-resin adhesion.

Abstract: With the launching of the Mauritius Sustainable Island project in Mauritius for sustainable development, Green and Sustainable Buildings are being constructed in Mauritius. The use of materials has an impact on the design of these buildings. A survey was consequently performed to find the materials presently used in the country, materials that are being used in GSBs and the prospects of GSBs in Mauritius. Apart from the use of concrete and steel, other novel materials are being used, especially those that can be used in sustainable buildings. As for GSBs, there are presently only two in Mauritius. However, all the stakeholders in the construction sector are very optimistic of an average to rapid movement towards GSBs in the next 10 years.

Abstract: Ha Tai railway passenger dedicated line is a national key project of the eleventh five-year plan. Its different from other construction of high-speed railway because there is many frozen soil over the place. The requirement of the subgrade material is higher.We proposed a idea that gradred broken stone mixed with cement and fine powder applied in the project.The compressive strength,splitting tensile strength and flexural strength were studied and analyzed through laboratory test.And regression analysis between compressive strength and flexural strength was made .According to the regression analysis,a power exponent function between flexural strength and compressive strength was got.Based on this,the corresponding relationship table was deduced,which can be used in practical projects.