Advanced Materials Research Vols. 450-451

Abstract: This paper first studied aluminum alloy honeycomb sandwich panel in out- plane static compress test.Through analyzing deformation characteristics, the loads-displacement relationship was obtained and are described by the average stress-strain curve. Secondly, using the Split Hopkinson Pressure Bar device of impact test, deformation behaviour，dynamic average stress-strain curve data and so on were got under different loading rates, thus learned impact dynamics characteristics of that.

Abstract: Architectural designing, creating new form and often unknown structural assemblies, is, we argue, distinct from structural engineering approaches that focus on the dimensioning of members in well-understood kinds of assemblies. Based on a review of compositional approaches, we offer in this paper an appraisal of the dominant educational approaches in structural engineering and architectural design. Based on current trends in both professions, we anticipate a future that sees architectural and structural engineering responsibilities no longer strictly separated but collaboratively integrated, in a way that harnesses benefits of specialist expertise, yet–somewhat reminiscent of the role of the medieval master builder–recognizes the need for generalist awareness and oversight required to achieve architectural and structural innovation. From this position, we propose a learning approach for architectural students that focuses less on rote learning and calculation and emphasizes applied learning through model building and the development of "structural commonsense" through the detailed study of precedent case studies.

Abstract: Mineral admixture was one or more industrial waste, or mixed with finely ground natural minerals, or grinded mixture.By replacing part of the cement with mineral admixtures , cement could be saved and improved the performance of concrete. In this paper，the compressive strength and slump of the concrete with mineral admixture were tested. The amount of cement replaced by mineral admixture in the concrete affected the compressive strength and the slump. According to the compressive strength and slump of the concrete, the optimum dosage of the mineral admixture was from 30% to 40%.

Abstract: In recent years the research on Surface-initiated longitudinal cracking along wheelpath (or Top-Down cracking) is become a fresh hotspot in the field of pavement damage focused by international asphalt pavement engineering.Because the traditional load is the vertical surface load with uniform tire pressure, this loading is applied at only one position and no effort is made to distinguish between tire pattern.The traditional method can’t explain the mechanism of the top-down cracking. In order to discuss the mechanism of TDC, this paper establish a 3D finite element model of semi-rigid pavement structure and use the large finite element software Abaqus. The analysis shows that, in the crack beginning stage, the main tensile stress appears under the center of the load on the sub-base of the pavement,and its value increases with the time. When cracks appear in the base, the position of the main tensile stress appears at the bottom of the surface layer, under the outside edge of wheel path. The value of the main shear stress increases at the stage of the cracks beginning, but the increase is small. The value of the main shear stress decreases when the cracks appear in the middle of the surface layer, and the position of the main shear stress changes with the depth of the cracks. With the increase of the cracks’ depth, the adverse influence of the shear stress becomes weaker and weaker.So the key of controlling the cracks in the surface layer is prevention. To prevent the development of the cracks, the tensile strength of the layer’s material should be enhanced in any way. The stress and its value resulted from the vehicle loaded on the structure layer is bigger than the other cases when the position of the cracks is at the edge of wheel path, and the stress is much bigger than the shear strength and the fracture toughness of the material of the layer. As the shear strength of the material is not enough, the vertical cracks are easier to appear at the edge of wheel path under the load of the vertical. Once it appearing, the cracks will extended into the layer because of the load of vertical. Eccentric load generates greater stress in the structure than the load loaded upright. In fact, though, non-channeling can reduce the appearance of the tracks, eccentric load enhance the development of the cracks in the surface because of the existence of the cracks in the surface layer.

Abstract: It is introduced that laser shock peening is suitable for machining metal micro components. The micro scale effect and elastic-plastic theory of micro scale laser shock processing were analyzed and discussed. The research status, mechanism, key technology and influence factors of microscale lager shock peening were summarized and the problems in microscale lager shock peening were analyzed, which provides guidance for further research.

Abstract: Based on data from Indonesian Directorate General of Mineral and Coal Technology, popular sources of silica sand in Indonesia can be found: Bangka Belitung, Pangkal Pinang,South Sumatra, Lampung, West Kalimantan, South Kalimantan, West Java, and East Java. Unfortunately, the use of silica sand in concrete mix is still limited as filler material. The challenge is then to explore the use of such silica sand, for instance in the form of nano silica. This research work explores silica sand from: Bangka Belitung, Pangkal Pinang, Lampung, West Java, East Java, West Kalimantan and South Kalimantan. The selected silica sand are then processed by the novel method developed by Indonesia Center for Ceramics using Polishing Liquid Milling Technology. The result is expected to contribute in the development of increased added value of locally available silica sand and to advancing application of nano silica for concrete.

Abstract: Bauxite tailing waste or commonly known as red mud is considered to be a very hazardous material. The using of red mud to make alternative building material has been widely studied for many years. Geopolymer as one of the breakthrough in the searching of ordinary portland cement/concrete substitution provides many options and possibilities of using different types of pozzolanic or alumina-silica materials. In this study, the using of red mud in metakaoline-based geopolymer paste has been studied in three different curing conditions for 7 days of sample age. Each sample then characterized both, macroscopically and microscopically including compressive strength testing, SEM photograph, XRD and FTIR spectroscopy

Abstract: Cementitious capillary crystalline waterproofing coating was developed, whose doping quantity of active substances was primarily determined by using orthogonal tests, the doping quantity of the active substances and the cement-sand ratio were optimized, and the formulation of the waterproofing coating was: 50.45% of silicate cement, 40% of quartz sand, 2.4% of assistants and 7.15% of active chemical substances. Test results showed that all the properties of the developed waterproofing coating conform to standard requirements, the bonding strength of wet substrate reached 1.8 MPa, and 28d seepage resistance reached 1.3 MPa.

Abstract: In order to investigate transportation of sulfate solution in concrete and its influence factors, transportation velocity and crystallization areas of sulfate solution in concrete, porosity and pore structure of concrete were tested by methods of transportation crystallization test and evaporable water test. Results show that under temperature (20±2)°C and relative humidity (60±5)％ environment, sulfate solution permeate concrete wall and get to concrete surface in very short time. The decrease of water to binder ratio and addition of mineral mixture to concrete can decrease transportation velocity and crystallization areas of sulfate solution in concrete. The transportation velocity and crystallization areas have great correlation with concrete porosity with pore dia. > 30nm.

Abstract: The emergency disposal of urban rail transit needs to accurately estimate the emergency range and total affected passenger flow volume. The urban rail transit network could be simplified to an abstract model which is easy to be analyst based on the graph theory method. Considering the actual network back-turning lines and vehicle storage tracks of urban rail network, the emergency range could be estimated effectively. The affected passenger flow could be classified as different kinds based on the different paths of passenger flow. The classification of passenger flow mainly includes “delay passenger flow”, “detour passenger flow” and “loss passenger flow”. Considering the emergency range, the different affected passenger flows could be superposed over time based on the abstract model, then the affected passenger flow volume and virtual loss time could be calculated out. The results could provide basis for the emergency disposal in urban rail transit. The example analysis is verified the feasibility of this method.