Abstract: This paper presents the results of an experimental
study on the effects of elevated temperature on compressive and
flexural strength of Normal Strength Concrete (NSC), High Strength
Concrete (HSC) and High Performance Concrete (HPC). In addition,
the specimen mass and volume were measured before and after
heating in order to determine the loss of mass and volume during the
test. In terms of non-destructive measurement, ultrasonic pulse
velocity test was proposed as a promising initial inspection method
for fire damaged concrete structure. 100 Cube specimens for three
grades of concrete were prepared and heated at a rate of 3°C/min up
to different temperatures (150, 250, 400, 600, and 900°C). The results
show a loss of compressive and flexural strength for all the concretes
heated to temperature exceeding 400°C. The results also revealed that
mass and density of the specimen significantly reduced with an
increase in temperature.