Abstract: The compressive strength test and ultrasonic testing of C80HPC specimens were carried out. The effects of polypropylene fiber content on concrete bursting,mass loss,compressive strength and sound velocity before and after HPC high temperature were analyzed. The effect of different ultrasonic test distances on the ultrasonic velocity of concrete was analyzed. The results showed that the addition of PP fiber can significantly inhibit the impact of high temperature burst on C80HPC.The compressive strength of C80HPC specimen decreases with the increase of fire temperature. When the fire temperature is between 200 ℃ and 300 ℃, and polypropylene fiber is blended, the compressive strength of the specimens rebounded. With the increase of temperature, the ultrasonic sound velocity of the C80HPC specimen decreased. With the increase of the ranging, the ultrasonic sound velocity decreased, and the decrease was not large. The ultrasonic damage could be detected by ultrasonic sound velocity. The relationship between C80HPC compressive strength,fire temperature and ultrasonic sound velocity was established.

Key words: high temperature burst, high performance concrete, polypropylene fiber, ultrasonic testing