BEHAVIOUR OF STEEL FIBRE REINFORCED CONCRETE WITH BOTTOM ASH AS FINE AGGREGATE TO HEAT EXPOSURE

It is of utmost importance to investigate the resistance to fire of concrete, the most widely used construction material. Fire in a building can cause untold mishap. It has become necessary to study the effect of high temperatures on concrete. Another matter of importance is that concrete has become costly owing to the unavailability of sufficient component materials, especially river sand. It has hence become very essential to opt for a suitable replacement for sand and also to study its reaction to high temperature. In this experimental study, bottom ash has been selected for replacing sand. This owes to its resemblance in physical properties to that of sand. Steel fibres are also added to increase the crack resistance of this concrete. The mix designed was for M25 concrete under medium exposure condition. Cubes were cast by replacing 25% of sand with bottom ash. These were subject to heat treatment in a preheated oven, after a curing period of 28 days. The duration of exposure of the cubes was for one, two and three hours at 500 degree Celsius and 1000 degree Celsius. The compressive strength of these cubes were then tested and compared with that of control cubes. The results showed slight increase in compressive strength for the cubes containing bottom ash. The heat exposure in this case aided strength development in these cubes. It was also observed that the results obtained were satisfactory for M25 concrete.