| Concrete is a common building materials, because it have many inherent weaknesses, such as low tensile strength, low bending strength, poor fatigue property and poor toughness, so its application is limited someway. Therefore, it is suggested to making concrete combined with some new materials to conquer its defects. As new types of composite materials, steel fiber reinforced concrete and FRP strengthened concrete develop rapidly recently. In this paper, a series of basic experiments of those materials are conducted in this paper.The main research work is as following:(1) Four concrete compact tension specimens are loaded and one of the specimens is conducted electric testing strain experiment. The relationship of loading and the cohesive crack displacement is analyzed; and the changes of the cohesive crack tip and the neutral layer with loading is also analyzed.(2) The stress intensity factors of each group specimens are calculated. the relationship curve of the length of cracking damaged area and the maximum loading is deduced; the calculated maximum loading is compared with the experimental result; the changing law of stress intensity factors and the ligament position is analyzed in the paper.(3) The process of the experiment is simulated by ANSYS element analysis software to obtain the stress intensity factors. The calculated data is compared with the experimental results. and the difference is little each other.(4) The steel fiber reinforced concrete and the ordinary concrete columns strengthened by CFRP are conducted centre pressing experiment; The pressure, strength and toughness of concrete columns strengthened by CFRP are compared with corresponding mechanics property before strengthened; The load-deflection curve is acquired by electrical strain gauges equipment; The process of the experiment is simulated by ANSYS; The simulated stress-strain curves is compared with the experimental stress-strain curves, and the difference is little each other.
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