The Study And Application On High Performance Fiber Concrete

Concrete is the main material of civil engineering industry, and with the demand of the construction and development of technology, the properties of concrete and using technic develop rapidly. An obvious disadvantage existing in the concretes is that it's easy to generate cracks. Cracks of plastic shrinkage often appear at the initial of molded specimens, which causes damage to the concrete. Thus it is a significant subject that how to reduce or even eliminate cracks and improve the basic characteristics, volume stability and durability of concretes.Thinking of these situations above, and according to the former research of increasing flexible mechanism with fibers, this paper shows that the new type fiber concrete of high performance with fibers and using water reducing agent, slag, expand agent, can reduce the cracks'forming and developing, enhance the stability and durability, and assure the safety using age of structures.In this paper, first, according to the analysis of theories and mechanism, the effect to the workability, deformability, durability and mechanical properties of concretes with fibers, admixture agent and series of mineral admixtures is studied. And then the influence to the vary of tendency of slump loss, compressive strength, shrinkage, creep, elastic mold under static pressure, freezing and thawing reducing under the configuration method of different materials in this city is explored. At last the micro-structure of fiber concrete is studied by micro-analysis.The tests shows that the low filling ration of fiber in the concrete can decrease the slump of HPC, but can also reduce its slump loss. Fibers can increase the flexible and strength of concretes, when keeping the compressive strength in a low changing range, the antiflex resistance strength and split tensile strength may be increased with 15%, especially under the using of fibers and expand agent together. The using of fibers increase the concretes volume stability, and the result is much better with expand agent added together under proper addition range, which can reduce more than 10% shrinkage. The using of fibers also improved the impermeability and freezing and thawing resistance, the fibers addition of 0.9kg per cubic meter concretes causes the impermeability grade up to P10, and the freezing and thawing grade up to D150, improving the durability. The irregularity distribution of fibers can be seen from micro-structure, when the concretes damaged, the fibers pulled out. Fibers can well restrain cracks in concretes.As showed from this, the fiber concretes can improve the quality of construction project and durability of concretes projects. Using fiber concretes in the construction project has further benefits.