A paper on compressive strength of concrete subjected to elevated temperature

Abstract

The structural behaviour of concrete subjected to elevated temperature due to fire is governed by range of
temperature, duration of temperature, and material properties of concrete. The reduction in compressive strength ,crack
formation, spelling phenomenon, adverse effect on reinforcement etc. are some of the effects on concrete due to elevated
temperature. The mechanical properties of concrete, physical and chemical responses of constituents of concrete
variation in thermal gradients during the fire and post fire cooling operations are responsible to govern the structural
behaviour of concrete. Very less study is reported indicating the comparison of effect of elevated temperature, the method
of cooling for different types of concrete such as concrete with M20.The investigations were carried out on the
compressive behavior of M20 .Cubes of 150mm X 150mm X 150mm size were cast using M20 grade of concrete.
Specimens were heated in oven at temperature of 150o C and 250o C for 2 hours. Some of specimen were tested were
allowed to cool on their own by natural cooling while, remaining were quenched in water to provide maximum thermal
shock by jet cooling. This specimen was tested for compression in compression testing machine (C.T.M) up to first crack
loading. Effect of this on compressive strength was compared with control specimen. The weight loss increases as the
temperature increases and percentage weight loss was in natural cooling. The percentage loss in compressive strength
was more in case of natural cooling as temperature cooling as temperature increases. In meeting this objective the
effects of elevated temperatures on the properties of ordinary Portland cement concrete constituent materials and
concretes are summarized. The effects of elevated temperature on high-strength concrete materials are noted and their
performance compared to normal strength concretes. A review of concrete materials for elevated temperature service is
presented. Nuclear power plant and general civil engineering design codes are described. Design considerations and
analytical techniques for evaluating the response of reinforced concrete structures to elevated-temperature conditions
are presented. Pertinent studies in which reinforced structural elements were subjected to elevated temperatures are
described.