Key Engineering Materials Vol. 517

Abstract: In the construction of log building, the building's insulation effect is mainly achieved by the timber tightly connected, which usually requires a large flat timber that lead to the consumption of high-quality wood.In recent years, by the decline in quality of forest resources, existing log buildings are constructed with fast-growing wood which small diameter, and larger curvature. Compared with the traditional log building, the log wall constructed with fast-growing wood has wider gap, poor insulation and poor pest control.So it greatly increased consumption of firewood for heating.To compensate for this defect, this paper make a study of log building constructions wall structured with light weight earth material. Mixture of plant fibre and cement, is used as main reinforce component, together with raw soil to enhance the ability of anti-cracking and heat preservation, fixing the mixture of ligth clay on inner side of the construcion's wall to enhance the ability of heat preservation and getting smooth wall surface by fill the gap in the wall, and easy for decorating interior wall.

Abstract: To improve the utilization of tailings, the basic properties of tailings and theirs influence on self-leveling mortar performance are experimental studied in this paper. The results show that the tailings can completely replace the natural sand to produce self-leveling mortar since the advantages of better fluidity, less water consumption, smaller time loss and high strength. The strength decreases with the addition of mineral admixtures, but it can still satisfy the requirements of standard JC/T 985-2005 "Cementitious self-leveling floor mortar ". Moreover, this method reduces pollution and production costs effectively.

Abstract: Longevity, reuse and recycle can be effective in reducing environmental burden in the life cycle of building steel structures. Longevity is the most crucial element in reducing the environmental burden of building steel structures. Nevertheless, there are always a number of buildings that need to be demolished for physical, architectural, economic, and social reasons. When such building steel structures have been demolished in the past, their structural members have been scrapped for recycling. Steel, by nature, is the only type of structural member that can be fabricated. Even without special joints that facilitate demolition work, steel members can be reused after minor fabrication procedures such as cutting, drilling, and welding. In this paper we discuss structural performance of reusable members and practical examples using reusable members.

Abstract: This paper presents a review of the literature on long-term property of recycled aggregate concrete (RAC), which includes the long-term strength, shrinkage, creep, durability and fatigue behavior. Based on many investigations carried out at home and abroad, it can be apparently observed that there are many differences in long-term property between the normal concrete and the RAC. However the long-term property of RAC can be improved and guaranteed by selecting the recycled aggregates replacement percentage, optimizing the mix proportion design, appending fiber or to restrict the environmental conditions. This paper can be helpful to the comprehensive understanding and further research of recycled aggregate concrete.

Abstract: A man-made damaged model of a one-storey block masonry structure with recycled aggregate concrete (RAC) was tested on a shaking table The Wenchuan earthquake wave, El Centro earthquake wave and Shanghai artificial wave were selected and input to the model with different earthquake levels in the shaking table tests. The recycled aggregate concrete (RAC) block masonry structure was damaged firstly by cutting the tie columns and its seismic behavior was experimentally investigated. The dynamic characteristics, the displacement response, the acceleration response were record. In comparison with the intact model, there is an obvious decrease in the seismic performance of the RAC block masonry man-made damage model.

Abstract: Double thin skin hybrid walls filled with demolished concrete lumps (DCLs) are composed of two steel plate skin connected by rib plates, with the space between them filled with new concrete and demolished concrete lumps. In order to investigate the seismic behavior of double thin skin hybrid walls filled with DCLs, quasi-static tests of seven specimens were conducted. The parameters considered in the tests are: replacement ratio of DCLs, thickness of steel plate, axial load ratio, rib plate spacing and height-width ratio. Test results show that the seismic performances of double thin skin hybrid walls filled with DCLs are similar to the walls without DCLs, and the double thin skin hybrid walls filled with DCLs also exhibit acceptable ductility and energy dissipation ability.

Abstract: Environmental preservation has been a theme debated in virtually every country in the world. Many measures are being taken to reduce the environmental impact due to unplanned development. Growing environmental restrictions to the exploitation of sand from riverbeds have resulted in a search for alternative materials to produce fine aggregates, particularly near to larger metropolitan areas. Artificial fine aggregates then appear as an attractive alternative to natural fine aggregates for concrete. This work is the final part of a study about the use of residues in concretes. Conventional Concrete (CC) and Self-compacting concrete (SCC) were developed replacing the natural sand by two types of mineral waste. Fresh state tests such as slump-flow, L-box, V-funnel test and column test were performed according to the Brazilian standards. The rheological characteristics (yield stress and plastic viscosity) of the SCC were determined using the BTRHEOM rheometer. At the hardened state, compressive strength was determined at 3, 14 and 28 days of age. Modulus of elasticity test was carried out at 28 days. Curves to mixture design were obtained to SCC and CC. For all mixtures and properties analyzed the good performance of the mineral waste used was proven. Finally and more important, it was demonstrated that it is possible to obtain structural self-compacting concrete, self-compacting concrete without structural purposes and conventional concrete by using mineral waste that works like fine aggregates and that on the other hand, without any destination, would cause serious environmental impacts.

Abstract: The Brazilian market of wood panels is in a consolidation process and presents great dynamism, which requires the search for new alternative raw materials that may contribute in quantity and quality to the continuous increase of this economic sector. Transforming residues generated by Brazilian agricultural industry and forestry sector into high quality panels is an interesting solution for solving raw material demand problem. The present work aims to show the potential of different types of residues for panel production showed in several research works, which were conducted in the Experimental Unit of Panel Production (UEPAM) located at the Federal University of Lavras (UFLA), Minas Gerais state, Brazil. According to results obtained, sugarcane bagasse, candeia wood and castor oil bean husk were the most promissory residues for particleboard production among the materials studied.

Abstract: Recycled concrete is a kind of new construction materials, and now received more and more attention from researchers and engineers, since its application in engineering projects can well cater to the increasing requirements of development for economic and environment-friendly society. Based on the pseudo static test of five recycled reinforcement concrete frame columns with different experimental axial compression ratios from 0.3 to 0.65, their failure modes, failure mechanism, hysteretic behavior, skeleton curves, bearing capacity, rigidity, ductility and energy dissipation capacity were discussed. Some possible influence factors and disciplines were also selected and analyzed. The study indicates that recycled reinforcement concrete frame columns in the case of relative low axial compression ratios usually exhibited similar and steady mechanical properties with common concrete columns. With the increase of axial compression ratio, its ductility and energy dissipation capacity are decreased and destruction forms tended to obvious brittle fracture, though its bearing capacity could slightly rise. The test results and analysis also manifest recycled concrete had expectative application potentials in most case.

Abstract: Fly and Bottom ash a coal combustion residue of thermal power plants has been regarded as a problematic residue all over the world. This study presents the results of testing for resilient modulus and permanent deformation to evaluate the mechanical properties of a soil stabilized with fly or bottom ashes, with and without lime addition. The soil tested is a regional sandy soil, which is not suitable for use in pavement works. The addition of fly ash with lime improved their mechanical properties, these being dependent on the ash content, moisture and number of load cycles. However in the mixtures only with ashes, the improvement was lower than the mixtures with ashes and lime. It was performed a paving project to assess their competitiveness as a base material for pavements. The results of this project showed that the soil stabilized with ashes is competitive for low volume traffic roads, with the advantages of minimizing the environmental problems caused by coal ash disposal.