Advanced Materials Research Vols. 690-693

Abstract: Previous studies have indicated that the density and the cost are high,and construction are difficult for radial curtain composite plybamboo.This paper presents a study on the high pressure and low pressure manufacturing technology of medium density radial curtain composite plybamboo.The results showed: the high pressure technology was optimum manufacturing technology of medium density radial curtain composite plybamboo,and the technology conditions were: hot pressing temperature was 140 °C, high pressure maintaning time was 80s/mm at 4MPa, high pressure maintaning time was 100s/mm at 3.5MPa.

Abstract: The particle characters and their physical properties of vertical roller mill finish grinding cements were studied in this paper. The difference with roller press-ball mill combined grinding products was also analysis. The results were shown that the particle size of the vertical roller mill finish grinding cements was more evenly distributed at the comparative average size. The proportion of the particles under the 3um and on 60um has fallen off a little; the average circularity and slenderness ratio were nearly same with combined grinding process, but the proportion of high circularity particle is lesser, and the particle shape were slightly inferior with the cement produced by combined grinding process; the physical properties were nearly same with the combined grinding cement except the longer setting time. So the cement produced by vertical roller mill finish grinding process is satisfied for the usability requirements.

Abstract: Based on unified strength theory, the mechanical behavior of core-concrete of concrete-filled square steel tubular stub columns was analyzed. Through controlling the constraint effect between square steel tube and core-concrete by width-thickness ratio, the ultimate bearing capacity formula for concrete-filled square steel tubular stub columns under axial compression was proposed, and the influencing factors of which was also discussed. The rationality of proposed formula was proved from the comparison of the analytical results obtained in this paper and experimental data.

Abstract: Paleosol is an important factor affecting the stability of loess slope, and its mechanical properties, deformation and failure mechanism are still under in-depth exploration and research. Here based on the GDS Lab System, using equivalent sine wave progressively loading mode of strain controlling, in order to reveal the dynamic strength characteristics of Paleosol under the vibration effect. The result show that:① there is an obvious phenomenon of stress relaxation during the cyclic loading test on Paleosol; Paleosol is high-consolidated clay, when the given confining pressure less than the natural confining pressure, the degree of stress relaxation increased at first and then decreased,to the contrary first decreased and then increased.② under the 50kPa、80kPa、100kPa confining pressure, the dynamic failure stress of Paleosol is 0.176kN、0.2302kN、0.2555kN,the dynamic failure stress increases linearly with the increase of confining pressure. The correlation coefficient is 0.9009 and the linear regression equation is б_d=0.001б₃+0.0958.③ On the basis of Molar Coulomb failure criterion, We obtained the index of dynamic strength of Paleosol, which was C=25.63kPa and φ=14º, by Molar Circle. In comparison with the static strength, the internal friction angle and cohesion decreases significantly, show that the Paleosol have obvious characteristic of brittle.

Abstract: In order to investigate the mechanical properties of concrete beams strengthened with CFRP sheets under load conditions, according to the reinforcement ratio, three groups of twelve concrete beams were made, each group included an common concrete beam and three prestressed CFRP sheets reinforced beams. Then the test with two-point loading was completed and the test date were obtained. On the basis of the test data, load state of concrete beams strengthened with prestressed CFRP sheets can effectively improve the ultimate bearing capacity, limit crack development and ameliorate the section stiffness.

Abstract: The orthogonal design can make sites in the test range uniformly distributed, which is introduced to slope sensitivity analysis, and can greatly reduce the test times and gets a good test effect.The paper takes the flood discharging tunnel import slope of Jinchuan hydropower station for example, which is a rock slope. This article selects the bulk density, internal friction angle, cohesion, earthquake acceleration four factors to design the orthogonal experiment, and the safety factor of the slope as a test indicators, using the simplified Bishop method of limit equilibrium theory to calculate the safety factor and analyses the slope sensitivity. The results show that the cohesion and earthquake acceleration are the most sensitive factors, and have a very significant impact on the slope stability.

Abstract: In order to analysis the polymer mortar performance, with different steel content polymer mortar specimens by compression tests, bending tests, scanning electron microscopy method, test results indicate that: 3% of the cement dosage and cement dosage compared to 0%，flexural strength of polymer mortar increased 26%, compressive strength increased 6%, fold compression ratio increased accordingly. However, when the dosage is higher than 3%, resulting in large specific surface area of cement, bending strength and compressive strength has declined.

Abstract: This article embarks from the nature and social economy conditions of the Three Gorges Reservoir in Chongqing. It has analyzed the question which the Three Gorges Reservoir’s countries meet about sustainable development and initially proposed the guidance pattern of countryside sustainable development, Agricultural industry, ecological agriculture, characteristic agriculture and village traveling. According this, it provides the countermeasure and suggestion .So it provides the reference for the economy development of the Three Gorges Reservoir’s countries and the new rural reconstruction.

Abstract: The article issued the influence on concrete durability caused by concrete admixture, based on the further study on concrete admixture bleed air performance test, and researched the influence on concrete durability caused by it. The experiments show that the admixtures of air-entraining performance improve internal pore structure of concrete and increase the compacting condition concrete. Concrete admixture also can improve the impermeability of concrete frost resistance and improve the resistance to environmental actions, and proposed concrete air content of the Dalian region suitable value.

Abstract: In the theoretical basic of only mixing the pulverized fuel ash, the slag or the silicon ash experiments, carrying on concrete alkali-aggregate reaction experiment separately that double-doped the pulverized fuel ash and the silicon ash, double-doped the pulverized fuel ash and the slag, double-doped the slag and the silicon ash, three-mixed the pulverized fuel ash, the slag and the silicon ash. The result indicated the effect of mixing pulverized fuel ash and the silicon ash is better than the mixing silicon ash and slag or pulverized fuel ash and slag. Besides three-mixed the pulverized fuel ash, the slag and the silicon ash can effectively suppress the reaction of concrete alkali-silica acid response（ASR）