Study On Performance Of The High Strength And Hybrid Fiber Reinforced Self-compacting Concrete

As one of the most basic engineering materials, concrete has been the most common and widely used in the field of engineering. However, with the growing species and growing scale of engineering structures, the requirement of concrete is higher and higher. High strength concrete, the self-compacting concrete, fiber concrete and other new type of high performance concrete gradually replace the traditional concrete, and obtain the people’s attention and favor. It is hot topic in concrete research at present that how to combine the advantages of various kinds of high performance concrete, and formulate the concrete of the excellent self-compacting performance, mechanical performance and durability. Based on the mixture ratio design and trial in this paper, successfully formulate the high-strength self-compacting concrete of meeting the working performance and strength requirements. In order to improve the mechanical properties and durability of high-strength self-compacting concrete, it mixes different kinds and different dosage of fibers on the basis of existing mix proportions. It finally successfully formulates the basalt fiber high-strength self-compacting concrete, the polypropylene fiber high strength self-compacting concrete and the hybrid fiber high-strength self-compacting concrete through adjusting the dosage of water reducing agent, and it carries on the experimental study and theoretical analysis on the workability, mechanical properties, durability and the microcosmic performance. It mainly completes the following several works:(1) It carries on the preliminary trial of fiber high-strength self-compacting concrete by adjusting the dosage of superplasticizer. It refers to the domestic and foreign regulations specified in the performance test and analyses that the fibers how to influence on the properties of high-strength self-compacting concrete. The results of test show that the fiber high-strength self-compacting concrete have the performance of slump within2h.(2) It carries on the mechanics performance test on the fiber high-strength self-compacting concrete, and analyses the influences and the effect of fiber high-strength self-compacting concrete compressive strength, splitting tensile strength and different elastic modulus. The results of test show that the basalt fiber and the hybrid fiber high-strength self-compacting concrete can significantly improve the mechanical properties of high-strength self-compacting concrete.(3) It carries on the hydraulic permeability and the freezing-thawing resisting cycling test of fiber high-strength self-compacting concrete, and analyses the effects of fiber high-strength self-compacting concrete on the permeability resistance and freeze resistance. The results of test show that high-strength self-compacting concrete with high impermeability and frost resistance, blending fibers can improve the ability to resist freeze-thaw of concrete. (4) The electron microscope and mercury intrusion method is utilized to test the internal microstructure and pore structure characteristics of fiber high-strength self-compacting concrete. It analyses that the fibers how to affect microstructure of high-strength self-compacting concrete through the study of microstructure and pore structure. The results of test show that blending fibers can refined pore size distribution and optimized the microstructure performance of the self-compacting concrete.