Applied Mechanics and Materials Vols. 174-177

Abstract: China's cement and concrete industry is still in rapid development period. Cement production and application consumes amount of mineral resources and fuels. A mass of greenhouse gases are released. Resource consuming and greenhouse gases releasing has a direct impact on resource depletion and global climate change. By using new technologies to reduce consumption of cement and concrete is of importance for conserving resources, reducing emissions and achieve the sustainable development of the industry.

Abstract: The desert sand from Maowusu sandy land is very fine aggregate. Currently, there are no national specifications concerning the application of desert sand with very fine grain. To apply the desert sand to concrete in civil engineering, concrete specimens made of the desert sand had been tested in order to clarify its engineering characteristics. On the basis of determined chemical composition and physical characteristics of the desert sand, the mechanical properties of concrete made of fine aggregate from Maowusu sandy land were investigated. The results of the tests indicated that the desert sand could be used as a fine aggregate in concrete for general civil engineering. At the same time, the desert sand was used to confect high strength concrete, the strength and workability of which met general engineering requirement, which provided references for high strength concrete preparation in these regions

Abstract: The search for a simple, accurate model to predict the sintering behavior is still a valid challenge facing the particulate materials industry. In spite of the sophistication of the before proposed methods, most models have not yet attained a desirable level of applicability. All just describe the micro sintering process but fail in controlling the densification behavior. The master sintering curve (MSC) is a model in densification which can adequately predict sintering results and is independent of heating history. The MSC can give better understanding of arbitrary sintering process and be introduced into industry production successfully. This paper provides a detailed overview of the MSC, including the construction, application, complications and some improvements of the concept.

Abstract: Different types of coarse aggregates have distinguished petrological, petrographical and mineralogical and local characteristics, thus, their effects on concrete strength development are quite significant, various and unpredictable. So, the laboratory investigation on the concrete mixtures using local aggregates becomes very necessary before used in engineering practice. This paper carried out the evaluation of two types of coarse aggregates constantly used in Florida, including Miami Oolite limestone and Georgia granite, on their effects on the developments of compressive strength, splitting tensile strength and elastic modulus of concrete with time. And the prediction models based on ACI and Cario-Lew are evaluated and modified. The investigation results indicate that the concrete mixtures with Georgia granite aggregate tends to develop lower strength than those with Miami Oolite aggregate. And the modified models give better prediction on strength development of the concrete mixtures with aggregates often used in Florida.

Abstract: By means of testing corrosion resistance coefficient of different cementitious material under the sulfate corrosion experimental conditions, sulfate resistance of cementitious material and assessment method are studied. The results show that 90d is proper corroded age for assessment sulfate resistance of cementitious material by corrosion resistance coefficient method, and the assessment method is put forwarded. Sulfate resistance of cementitious material can be divided into five classes according to corrosion resistance coefficient assessment method as follows: “very low”, “low”, “moderate”, “high” and “very high”. The sulfate resistance of Portland cement is better than ordinary Portland cement, and both of them are low. Mineral admixture with proper content can improve sulfate resistance of cementitious materia largely, but do not always available to all content. Sulfate corrosion mechanism of different kinds of cementitious material is analyzed.

Abstract: Choosing abandoned polystyrene foamed plastics and actived carclazyte as the main raw materials, mixed with emulsifier, defoaming agent and many kinds of additives made into the excellent performance oily lacquer putty. The technological process of the lacquer putty was simple, using abandoned FPS and carclazyte as the main raw material can save energy and reduce the white pollution, which has the good social and economic benefits. The properties of the product were similar to the same kind of the others. The materials were easily gained and its production cost is lower. The lacquer putty was applied to inlay glass or level up holes and slots.

Abstract: Structural Finger-jointed (FJ) lumber is a common building material used mainly in timber construction. The paper evaluated the factors influencing structural performances of FJ Chinese fir lumber. Lumber was sawn from the logs following a pattern typically used in China to maximize the volume of recovered sawn timbers. After kiln-drying, the rough-sawed lumber was planned to 4.5 cm thick, 9.0 cm wide and 100cm long. The lumber pieces were assigned to two groups according to their dynamical MOE. FJ lumber is produced by cutting a series of sloping fingers on the end of the wood pieces to be joined and interlocking the two pieces by MDI glue. Bending and tensile strengths of FJ lumber were tested. The results show that the structural performance of the MSR FJ lumber was increased effectively after these units were machine-graded in advance and the interaction of variables should be considered in the design of finger joints.

Abstract: The effect of Cu doping on the conductivity of individual ZnTe nanowires was investigated. Cu was diffused into ZnTe nanowires during the heat treatment process. Cu content was controlled by the thickness of Cu layer sputtered on the top of ZnTe nanowires. I-V curves of Cu doped ZnTe nanowires have been tested by four-terminal measurement. The results indicate that the conductivity of Cu doped ZnTe nanowires is effectively improved. When Cu content doping in ZnTe nanowires reaches 17.5%, there is about five orders of magnitude improvement in the conductivity of Cu doped ZnTe nanowires, compared with undoped ZnTe nanowires.

Abstract: Concrete bubble is a common phenomenon in the concrete construction process. Generation and existence of concrete air bubble not only influence the concrete appearance, but also affects concrete service life. Especially for concrete surface with high requirements just as water diversion tunnel, concrete bubble gradually raises concern of engineering construction parties. Engineering technical personnel take a number of measures to eliminate concrete surface bubble in project practice. Based on analysis of many bubble elimination methods, generating mechanism and treatment measures of concrete bubble are discussed, providing reference for eliminating concrete bubbles.

Abstract: Polyurethane foam is an important branch of building insulation materials, but its poor fire performance easily to lead to smoldering. This is conducted under condition of natural convection and heating time change of smoldering experiments on the smoldering experimental compartment. Use the thermocouple to measure the temperature changes inside the material. The results shows that, the heating time is shorter, smoldering into flame combustion is less complete, when time is short enough, smoldering extinguished; and in the vertical smoldering propagation, as time is shortened, smoldering into open fire’s position is upward. Experiment and analysis can be nicely displayed the effect of heating time on smoldering process.