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Ultrasonic Test Analysis of Impact Damage of Polypropylene Fiber Mortar

The method recommended by ACI Committee 544 was used in this paper. Drop hammer impact tests based on mortar specimens with different contents of polypropylene fiber were carried out. The Ultrasonic test is done before and after impacting. Under different drop hammer impact times, polypropylene fiber mortar specimens' damage degree was evaluate based on ultrasonic velocity. The results show that the hammering number corresponding to the impact fracture of polypropylene fiber mortar is more than ordinary mortar. The ultrasonic velocity of all specimens decreased gradually during the process of hammering, but adding the right amount of polypropylene fibers can effectively slow down the rate of wave speed decline.