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The concrete structure is the most widely used form of structure in the national infrastructure, but ordinary concrete under harsh environmental conditions due to the durability of the adverse result itself flaking, damage or even destroy, the high-performance concrete (HPC) came into being. High performance concrete is designed to guarantee the performance and mechanical properties of concrete work, focus on improving its durability. In this paper, the performance of a variety of high-performance concrete admixtures, fly ash, silica fume, polypropylene fiber. Doped with different proportions of single, complex doped cement replaced by the same amount, and thus make the mix ratio adjustment, optimization, identified 17 groups with the ratio, compressive strength, tensile strength and durability test study in each group . The main conclusions are as follows: (1) fly ash, silica fume mineral admixture can improve the performance of concrete, so that it does not bleeding, not isolation, cohesiveness; fly ash concrete can improve late strength; silica fume activity, favorable to the early strength of concrete; certain proportion between complex doped, can play a superimposed effect, making each age strength were increased; addition of fiber concrete strength had no effect or slightly reduced, but It does not cause greater damage. (2) fly ash and silica fume added can be different degrees of improve concrete impermeability capacity, silica fume finer particles on concrete impermeability increased more favorable; such complex doped or adding a small amount of fiber, impermeability better. (3) concrete carbonation depth increases, with the fly ash increases as the silica fume content increases slightly reduced, but the overall depth of carbonation, not caused by the nature of the protective layer of concrete destruction. (4) a certain amount of fly ash or silica fume can improve the frost resistance of concrete admixture excessive will reduce concrete air, resulting in decreased frost resistance; fiber can also be appropriate in order to moderate excessive The dosage will increase the weak interface, resulting in decreased frost resistance. (5) For the drying shrinkage of concrete, fly ash can be appropriately reduced drying shrinkage values ??of each age, and silica fume concrete shrinkage due to fast hydration adverse view of this, complex Fly Ash and silica fume or adding fiber to improve. (6) the durability of high performance concrete is a complex issue, according to different structural parts in the actual project, different durability requirements, selected mineral incorporation, targeted to improve the durability of concrete.
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