Papers by Keyword: Experimental Research

Abstract: In order to further investigate the stress-strain curve of carbon fiber reinforced concrete, the curve of stress-strain is used segmentation tabulators on the basis of the existing tests. Based on the axial compression experiments of 9 carbon fiber concrete reinforced samples filled with different carbon fiber admixture amounts, the theoretical calculating formula of the stress-strain curve with different admixture amounts was proposed, and the theoretical formula of calculation parameters and carbon fiber volume fraction was putted forward. The experimental results show that the calculation parameters of the stress-strain curve increases with the increase of the carbon fiber admixture amounts. The theoretical calculating formula of the peak strain and carbon fiber volume fraction, the compressive strength, and the calculated results agreed well with the experimental results.

Abstract: By using a solar air collector module with independent design as the object of study, obtained the temperature distribution of collector module in various conditions through experimental studying of its structure and operating parameters. The experimental results show that adding bulkhead in collector module and increasing the collector plate openings of collector module can enhance the heat-transfer by convection between air and collector plate. At the same time, the outlet air temperature of collector module is significantly higher than the temperature of the collector plate; On the other hand, the maximum temperature difference between import and export can reach to 333 K when the collector plate is 90° corrugated table-flap. And this condition has the maximum temperature difference between import and export in all conditions at some point.

Abstract: The application of regenerative combustion technology to industry burners has been a huge success. This paper presents an experimental study on the change of the temperature field and the concentration of NO in the flue gas in an industrial furnace. The result showed that the concentration of NO increased with the rise of temperature. For the reversing time of 20s, 40s, 60s, and 80s, the temperature of each point changed in accordance with similar rules, but the temperature of the former three measuring points did not obviously change. The heat transfer occured mainly in the last two layers of the regenerative cells, and the utilization of all the regenerators was only 40 percent. The heating curve of the sixth measuring points was significantly different from the cooling one. With the increase of the reversing time, the flue gas and the air temperature variation also increased.

Abstract: The bottom surface of the bridge beam, which is made of C50 high-strength concrete, is heated to 800°C in fire-resistant experiment. Then the elastic modulus and strength of the concrete are measured by the rebound method and core sampling method, and the test results are used to validate the theoretical methods. The study shows that the strength and elastic modulus of concrete decrease with the increasing of temperature. The strength from the current theoretical analysis agrees well with that from the experiment. But for the elastic modulus, there is a great difference between the theoretical and experimental analysis. The strength of the concrete after fire gotten from the rebound method has a bigger error than that from the core sampling method, so that the core sampling method should be used in preference.

Abstract: Retard-bonded prestressed concrete which has appeared in recent twenty years is a new and distinctive prestressed system. For the research on mechanical behavior and service property of retard-bonded prestressed concrete members, retard-bonded prestressed strands were made by manual work in this paper. Experimental research and theoretical analysis of three retard-bonded partially prestressed concrete T-beams were carried out under static loadings. The law of crack development and distribution both with the relationship between load and maximum crack width were studied in the paper. Test results were contrasted with experimental studies of two traditional partially prestressed concrete T-beams, and the characters and merits of retard-bonded partially prestressed concrete T-beams were obtained. It provides theoretical reference for the actual project application of the new retard-bonded prestressed concrete system.

Abstract: In order to verify the characterization degree of water stability, research selects some clay content aggregate retrieved from road engineering field to produce rubber asphalt mixture and carry out the water stability test. Test results show that clay content in aggregate has a significant influence on the water stability of rubber asphalt mixture. When the content of clay in aggregate less than 1%, the influence on water stability is smaller; when the clay content exceeds 2%, the decay rate on water stability performance and long term properties obviously speed up, resulted in serious water damage.

Abstract: The recycled aggregate is dealt with in three ways, the first way is to keep the recycled aggregate intact; the second way is to wrap the recycled aggregate in cement slurry of Water-cement ratio 0.55 for 30 minutes, and then place it at room temperature for 7 days; the third way is to immerse the recycled aggregate in water for 24 hours. Three kinds of different recycled aggregate is separately used for mixing of recycled concrete. The strength and slump of recycled concrete with different recycled coarse aggregate contents are tested. Experiments show that the recycled concrete produced by using the recycled aggregate immersed in water and selecting a suitable mix has the higher strength and slump，which can be industrialized. And then, the recycled concrete with 40% recycled coarse aggregate contents is used in the steel-reinforced recycled concrete beams, which are tested, the failure process of steel-reinforced recycled concrete beams,section strains and maximum load are acquired. Research shows the steel-reinforced recycled concrete beams conform to plane hypothesis before the load reachs 80% the limit load, the flexural bearing capacity of the steel-reinforced recycled concrete beams can meet the demand of Technichal Specification of Steel-Reinforced Concrete Structures. The use of recycled concrete in the composite structures is proposed.

Abstract: Static tests were conducted on integral structure of light steel temporary buildings under wind load. The mechanical behavior and the deformation performance of the structure were investigated. A kind of new system of load distribution beams was applied, which imposed the horizontal loads and simulated the uniformly distributed wind load. The load-displacement curves of the columns were obtained. And the strains of the columns and the wall panels were obtained also. The performances of the light steel temporary building are summarized and discussed.

Abstract: Due to complex down-hole conditions and longer drilling time, there are serious casing wear in deep and ultra deep well. It is necessary to carry out a deeper research of the casing wear. Theory of casing wear and prediction method are not perfect in deep well and ultra deep well .The purpose of this paper is to obtain the wear efficiency and friction coefficient which is used to predict wear of the TP140 casing in down hole. A block-ring casing wear tester is specially designed and produced. The wear efficiency and coefficient of friction which is used to predict wear of TP140 casing in different density polysulfide water-based mud is obtained. The influence of the mud density on the TP140 casing wear resistance is analyzed. It is found that the larger mud density, the bigger casing wear efficiency and the friction coefficient.

Abstract: Frame structure is widely used in practical projects. For jitter of the frame structure excited by median and high frequency disturbances, firstly, the dynamic model of thin plate substructure is built by wave method, and then the dynamic model of frame structure is established by combining wave method and substructure technique. At last, the accurate dynamic response was obtained. The simulation of dynamic characteristic is made, and simulation results are compared with FEM results. On this basis, modal experiment and frequency response experiment is done to verify theoretical results. In comparison to FEM, the results by wave method are accurate in low frequency regions, and the results are more accurate in the median and high frequency regions. The experiment proves wave method is correct and effective for jitter transmission analysis of frame structure in the median and high frequency regions.