Seyed Yousef Jafari Naeini - MSc, Civil Engineering, Construction management, Islamic Azad University, Ahwaz branch,Ahwaz, Iran

In this paper , the ۲۸ day compressive strength test has been performed on samplesincluding normal fiber concrete and high strength concrete. Ultrasonic test (UT) as anondestructive and also, compressive machine (CM) as a destructive test was appliedand the results were compared. In order to investigate the effect of temperature,samples were subjected to ۲۰۰, ۴۰۰, ۶۰۰, ۸۰۰, ۱۰۰۰ and ۱۲۰۰ degrees Celsius and theduration of exposure was equal to ۳۰, ۴۵, ۶۰, ۹۰, ۱۲۰ and ۱۸۰ minutes. Based on theresults, it was observed that the minimum error observed between UT and CM testswas ۲.۹% and the maximum error between the two methods was ۱۰.۹%, which showsthe high accuracy of the ultrasonic test method in determining the specimen strength.The average probable error of the method is determined to be around ۶.۸%.Furthermore, according to the average reduction in compressive strength due to heatexposure time, it has been observed that the results UT and UM test have slightnumerical differences, however, the trend of changes and reduction of resistanceagainst the time for both types of tests is almost the same. Finally, the accuracy of theUT in determining the compressive strength of specimens in high temperatures is fullyconfirmed.

fiber concrete, high strength concrete, temperature, Ultrasonic text