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The purpose of paper is to gain a better understanding of the impact resistance of fiber reinforced concrete, and experiments were conducted on the impact resistance properties of alkali-resistant glass fiber of high zirconium and coarse polypropylene fiber reinforced concrete slabs with different volume fraction contents. From the dynamic point of view, the improvement effects of fiber type and fiber volume fraction on the impact resistance of concrete slab were studied through the failure morphology of the specimen, the acceleration time history of the drop hammer and the reaction time history curve of the bearing at the bottom, combined with the impact damage process of the whole specimen recorded by the high-speed camera. It is found that after the second impact, the damage degree of plain concrete and fiber reinforced concrete slab is different. The plain concrete slab is brittle and broken into four blocks in the diagonal direction. The slab of coarse polypropylene fiber reinforced concrete with the volume fraction of 0.75%, has the slightest damage with nine main cracks at the bottom of the slab, without large area concrete caving, and the deformation of the slab is large. The slab of alkali-resistant glass fiber of high zirconium reinforced concrete with the volume fraction of 0.75%, has nine main cracks at the bottom of the slab, the maximum crack width is only 0.8, cm, and the emergence of a round concrete caving area with a radius of about 8, cm at the bottom of slab is observed. Through the time history of acceleration, it can be seen that there are significant differences in the failure process of the slab between plain concrete and fiber reinforced concrete slab. In the elastic deformation stage, the duration of the impact of fiber concrete is about 1, ms longer than that of plain concrete. In the stages of crack propagation and concrete collapse, when the acceleration decreases to about 1/3 of the peak, the plain concrete slab shows the tendency of brittle failure. The acceleration time history curve of the fiber concrete slab shows the secondary strengthening, which is ductile failure. Fiber significantly improves the impact toughness of the sheet, and the higher the fiber volume fraction, the more pronounced the improvement in impact resistance. © 2018, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.
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