Applied Mechanics and Materials Vols. 174-177

Abstract: By means of accelerated carbonation tests, the carbonation resistance of concrete in relation to the variation of water-cement ratio, fly ash content and curing conditions is studied in this article. The results show that under the standard curing conditions, with the fly ash content of 20%, in response to different water-cement ratio, the carbonation depth of concrete and the water-cement ratio are presented more or less in a linear relationship. At the water-cement ratio of 0.40, there is hardly any carbonation effect onto the concrete. However, at the ratio of bigger than 0.60, the carbonation depth of concrete increases in a speedy way. Under the standard curing conditions, at the water-cement ratio of 0.55, with the fly ash content of lower than or equal to 30%, the carbonation resistance of concrete is good enough to fulfill the design criteria of 50~100 years for service life of important and general buildings, while the compressive strength declines by less than 10%. But under the condition of 1d curing with retention of moisture followed by curing in the air until 28d, with no fly ash content, the carbonation depth of concrete has reached 35mm, which fails to fulfill the design criteria of 50 years for service life of general buildings. It is therefore concluded that the control of water-cement ratio, the control of fly ash content, and the sufficient curing with retention of moisture in early stage are all the essential factors to ensure the durability against carbonation for the concrete with fly ash content.

Abstract: This study is intended to show possibility of using high strength steel for H-shaped beams with large depth-thickness ratio in the elastic range by conducting loading tests. Test specimens are manufactured with high strength steel of over 700N/mm2 yield stress. Elastic behaviors of such beams under cyclic loading are mainly concerned. In addition, the redundancy and the stability of these beams in plastic range are investigated. It is shown that these beams are useful as seismic design beams although the depth-thickness ratio of H-shaped beams is larger than the limit of current standards in Japan. Also, by referring to a recent study, a new limit value of plate slenderness ratio (depth-thickness ratio of web plate and width-thickness ratio of flange plate) is proposed.

Abstract: Lime Stabilized expansive soil is often used as filler in road subgrade, although many scholars have done a lot of research, the mechanical properties under wet and dry cycle role remains unclear. The paper Carried out direct shear test, consolidation test and CBR test on the lime stabilized expansive soil after the different times of wet and dry cycle. The test results show: The strength of soil will decrease, especially in previous cycle, and the trends can be expressed with logarithmic model; the deformation index (compression coefficient) of soil will increase, especially in previous cycle, and the trend can be expressed with powder model; through more cycles, no matter the strength or the deformation index of the sample tends to a stable value; the stable intensity is about 40%-60% of the original intensity.

Abstract: The small fly ash hollow block, compared with other traditional wall materials, has many advantages. If the block is put into production, it will bring huge environmental, economical and social benefits. This paper describes the technical points about the mix ratio test of the small fly ash hollow block.

Abstract: Abstract: In order to analyze the relation between surface roughness of Pyinkado plates and sanding parameters, an orthogonal experiment and a single factor experiment were performed. The results show that the mesh of the sandpaper has remarkable influence on surface roughness of Pyinkado plates, but the feeding speed and sanding thickness don’t; when the mesh of the sandpaper is 150, the feeding speed is 6 m/min and sanding thickness is 0..4 mm during the first sanding and the mesh of the sandpaper is 240, the feeding speed is 9m/min and sanding thickness is 0.15mm during the second sanding, the smallest roughness (Ra) was obtained as 2.81μm. Considering production efficiency, changing feeding speed into 9 m/min in the theory optimization scheme, engineering optimization scheme was obtained, and the wood surface roughness (Ra) is 2.91μm.

Abstract: Comparative tests on interfaces between different materials are performed by means of the self-developed NHRI-4000 high-performance large interface shear apparatus. Change of mechanical properties of interfaces between different coarse-grained soils and concrete is investigated owing to the differences of materials. The influences of the existence of slurry on the strength indices of the interfaces are analyzed. The test results show that shear failures all occur in the contact zone of specimens. The properties of materials and the differences of particle shapes have great influences on the strength and deformation characteristics of interfaces as well as the residual shape of shear plane after shearing. The specific exhibition is as follows: (1) the strength and deformation indices of rock-fill materials with distinct edges are significantly superior to those of sand-gravel materials with good roundness; (2) the existence of slurry leads to obvious decrease of mechanical indices of the interfaces.

Abstract: Through the investigation on the traditional houses of ancient village existing in Yubei village, this paper analyzed and classified the characteristics of the shapes and the technologies of the walls of traditional house and has described the factors that have influenced their generation and development. Basing on the construction technologies, from four different material of the wall such as boulder wall，brick wall，wooden board wall and plaster on bamboo slat wall, it has studied corresponding properties of materials, basic processes, construction principles, art forms and so on and it has researched on some methods and rules of construction of wall of traditional folk house in Yubei village.

Abstract: The paper brings information on grinding cement with high proportions of slag in the presence of amine alcohols grinding aids. Grind respectively blended cement with 20%, 50%, and 80% granulated blast furnace slag and analyse the evolution of the specific surface area at various grinding times and grindability. Results show that the specific surface area of belended cement depends on the content of slag and the type and ratio of grinding aid, and grindalility of the cement is also affected by grinding aids.

Abstract: Recently recycled coarse aggregate concrete tends to be developed by using waste concrete considering environmental issues and conserving natural resources. However, performances of recycled coarse aggregate concrete are relative low compared with ordinary concrete due to the differences between recycled coarse aggregates and natural ones. In this research, developed mill is used to shuck the cement paste adhering on the surface of coarse aggregates to obtain shucking recycled coarse aggregates. Experimental results demonstrate that the performances of shucking recycled aggregates and concerned concrete are both improved.

Abstract: This paper investigates environmental impacts of wood structure, reinforced concrete (RC) structure and steel structure in Taiwan in terms of embodied energy consumption and embodied CO2 emissions. The methodology of life cycle assessment (LCA) is applied to the analysis in building materials both from ‘cradle to gate’ perspectives and from ‘cradle to cradle’ perspectives. The results first show that wood structure with the resource from the USA has the least environmental impacts. In addition, as far as material recovery phase is concerned, the substitution effect of wood structure instead of RC and steel structure has an obvious increase as the recovery rate reaches more than 60%. To summarise, wood structure is beneficial for our environment not only in the construction phase but also in the material recovery phase.