Meso-level Numerical Study On Flexural Properties Of Fiber Reinforced Concrete With Different Incorporation Rate

Cement-based materials is the largest, and has excellent characteristics man-made building materials, but as more and more construction materials developed in the direction of high strength and high performance, its inherent weaknesses also become increasingly prominent. The composite material is one of the main substrate to improve the performance of cement-based materials , and using fiber-reinforced is the core. In recent years, steel fiber, polypropylene fiber and glass fiber reinforced cement-based materials developed rapidly, at the same time, engineering practice requires fiber reinforced cement-based materials to further deepen the basis of theoretical research.. Some basic theoretical issues such as crack propagation in the damage and fracture process and damage and fracture of fiber reinforced cement-based material , is a leading project in this area.In this paper, using numerical analysis software RFPA2D (Realistic Failure Process Analysis) owned its copyright by Professor Tang Chunan in Dalian University of Technology to simulate the flexural performance of the cement-based composites . Using Weibull random distribution function to describe the mesoscopic heterogeneity of cement-based materials,on this basis,elastic damage constitutive model of unit cells has been established, by incorporating stiffness degradation in material failure process to deal with initiation and development of crack ,in order to achieve the whole process simulation include micro-crack initiation, extending until through of fiber-reinforced cement-based specimen. Recycling the simulation results analyze failure law and the basic mechanical properties of different volume fiber reinforced cementitious composites in bending,to study the mechanism of its destruction, for providing theoretical guidance for the strengthening and toughening design to cement-based materials. This study include: 1 To the fiber reinforced cement composite materials(including glass fiber reinforced cement, polypropylene fiber reinforced cement and steel fiber reinforced cement)commonly used in engineering practice, understanding of their application, advantages and disadvantages, carrying on numerical simulation to them,and comparing numerical simulation results and the physical tests, by analyzing their failure modes, acoustic emission characteristics, flexural toughness, strength changes to study the failure mechanism. Analysis indicates that, regardless of steel fiber, glass fiber or polypropylene fiber, can significantly improve the toughness properties of cement matrix; Moreover, steel fiber and glass fiber of high tensile strength, its strength also improved more significantly.2 Collection of fiber reinforced concrete composite materials(including steel fiber reinforced concrete, glass fiber reinforced concrete and polypropylene fiber reinforced concrete)having more application in engineering,suming up their development and application, establishing of numerical Model of different content fiber concrete,through the simulation results analysing the law of crack growth in the failure process, the final crack patterns,the trend of the load-displacement curve, temporal and spatial distribution of acoustic emission, bending toughness and the measurement of bending strength to reveal the failure law and the strengthening and thoughening mechanism of fiber reinforced concrete. Studies show that the steel fiber and glass fiber can improve the flexural strength of concrete matrix, polypropylene fiber is a little effect on the strength increased; three kinds of fiber can significantly enhance the toughness of concrete, so that the destruction of the specimen gradually changes from brittle the ductility3 In special,numerical study on Partially High-Percentage Steel Fiber Reinforced Concrete(PHPSRFC)wih great potential for application and good value for money have been executed,the failure mechanism of PHPSFRC has been probed from crack propagation in failure process, acoustic emission characteristics, selecting the unit from top to bottom at the central area to analyse stress, comparison at the load-displacement curve and toughness with different contents specimen.comparison with full-doped steel fiber concrete specimens, the same number of fiber samples in PHPFRC better play in reinforcing and toughening effects. Relative to SIFCON, also greatly reduces costs, simplifies the construction difficult. Steel fibers in concrete cost has been greatly enhanced...