Advanced Materials Research Vols. 1065-1069

Abstract: The objective of this study is to realize a non-destructive characterization of cementitious materials using ultrasonic method. The motivation of our work is to show that the ultrasound can be applied not only in medical imaging but also in the assessment of construction materials, which is not widely known in this domain. In order to solve the problem, the ultrasonic velocity measurement was performed on the samples before and after carbonation of a standardized mortar at different periods. The results offer the possibility to determine the mechanical properties such as Young modulus E, shear modulus G and Poisson's ratio. This is an advantage for in-situ structures in comparison with destructive methods that require destroying the samples. The main contributions of this study are: 1) Ultrasonic occultation of cement materials is a reliable method with a small margin of error; 2) The values ​​of mechanical properties found by ultrasonic method are consistent with theoretical values ​​found in the literature; 3) The evolution of these mechanical properties is consistent with the densification of the microstructure during carbonation due to the formation of CaCO₃.

Abstract: Using numerical analysis to evaluate the mechanical properties of concrete is an important method emerged in recent years. However, some concepts and simulation methods need to be further investigated.

Abstract: Using numerical analysis to evaluate the mechanical properties of concrete is an important method emerged in recent years. However, some concepts and simulation methods need to be further investigated. This research used the test specimen for compressive strength of the concrete as the subject of numerical analysis; simulated the load to reach compressive strength and analyzed the stress field. Finally, yield strength of the concrete specimen is proposed.

Abstract: Numerical analysis was performed for compressive strength of the concrete. Internal defects of the concrete specimen were simulated and compressive strength reduction mechanism was studied because of angle..

Abstract: Numerical analysis was performed for compressive strength of the concrete. Internal defects of the concrete specimen were simulated and compressive strength reduction mechanism was studied. The defects inside of the specimen are stochastic; therefore it is impossible to study the subject with physical material testing. From this study, it is shown that numerical analysis can effectively simulate internal defects and provide an efficient way to study compressive strength reduction.

Abstract: Numerical analysis was performed for compressive strength of the concrete. Internal defects of the concrete specimen were simulated and compressive strength reduction mechanism was studied. The defects inside of the specimen are stochastic; therefore it is impossible to study the subject with physical material testing. From this study, it is shown that numerical analysis can effectively simulate internal defects and provide an efficient way to study compressive strength reduction.

Abstract: The objective of this paper is to quantify the influence of internal defect on the multiaxial strength. Numerical analyses are performed for the second and third axial strength of the concrete. The analysis result indicated the existence of defects not only decreases the strength of materials, but also changed the stress state of the specimen.

Abstract: In the paper, extrusion process of hollow aluminum profile was simulated using DEFORM-3D; the metal flow velocity of setting baffle-blocks before and after is compared. Three kinds of welding chamber depth of 10 mm, 13 mm, 15 mm were used respectively for extrusion process simulation and got die load varying pattern. Also the strain field and temperature field were analyzed. The results show that the metal flow velocity was more well-distributed by setting A、B、C、D baffle-blocks. When the weld chamber depth is 13 mm, the die load is the smallest. By analyzing the strain field and temperature field,The results showed that the major cause of metal temperature rising in the extrusion process is deformation energy generating in the process of metal plastic deformation.

Abstract: s. Using industrial waste residue as concrete mineral admixture has become a direction of the development of the green concrete. Nickel slag is mainly introduced, and the chemical composition and preparation of nickel slag powder, and study its physical properties, activity, volume stability and mechanical properties. According to nickel slag powder admixture amount of replacing cement, admixture fineness, mixed with admixture of concrete changes between the intensity of the three, put forward suitable fineness of slag powder and nickel content of concrete.

Abstract: Experimental study on the influence of the steel fiber types, content and water-cement ratio on the reactive powder concrete (RPC) performance is conducted. The results show the influence law that the 3 factors to compressive strength and shock-resistance of steel fiber RPC. In this sense, it is of vital importance to enhance structural strength, and to improve the anti-seismic and anti-detonating capacities of the key engineering in urban.