The effect of different fibres on the flexural behaviour of concrete exposed to normal and elevated temperatures

The paper focuses on studying experimentally the potential benefits (in terms of stiffness, strength, ductility) stemming from the use of different fibres on the flexural behaviour of concrete beam specimens. Different types of steel and polypropylene fibres were added into the concrete mix at volumetric contents of 0.5% and 1.0% either individually or in different combinations. Three-point bending tests were carried out to establish the behaviour exhibited by the fibre reinforced concrete specimens produced up to failure and determine the associated mechanical properties of the subject material. The residual mechanical properties of the same specimens were also established after exposing them to temperatures of 280 °C. From the test data obtained it was observed that even though the use of hybrid fibres can result in the development of higher residual tensile strength and improved toughness, at elevated temperatures, the use of steel fibres appears to provide optimum post-cracking behaviour.