An experimental investigation on torsional behaviour of recycled aggregate based steel fiber reinforced self compacting concrete

Abstract

The performance of concrete is highly influenced by its compaction integrity and brittle nature. Self-Compacting Concrete is a solution to all compaction related problems and can achieve consolidation without the use of vibrators. It's behaviour in various aspects is still need to be investigated especially in torsion. Torsion is one of the basic structural action which is low prioritized though very essential in analyzing the structures subjected to earthquake and wind loads. Torsional rigidity, toughness, twist at ultimate torque of a member plays an important role in analyzing structures subjected to lateral forces. Addition of steel fibers makes concrete a better energy absorbing material. Recycled aggregates can be used for sustainable development of concrete. From the literature, it was found that the studies on torsional behaviour of steel fiber reinforced recycled aggregate based Self-compacting concrete are scant. In the present study, self-compacting concrete beams with recycled coarse aggregate (25% replacement of total coarse aggregate by weight) were tested by varying aspect ratio (50, 70 and 100) of hook end steel fiber for constant fiber content of 0.5% by volume of concrete compared with Vibrated Concrete. A total of 32 beams were cast with 20 MPa and 80 MPa concrete with natural and recycled coarse aggregate. It can be observed from the study that there is a significant increase in torsional properties like ultimate torque, angle of twist, torsional stiffness, torsional toughness in self-compacting concrete compared to vibrated concrete for both natural and recycled coarse aggregate with the addition of fibers. Better performance was observed in members with fiber aspect ratio (70) in both concretes compared to lower (50) and higher aspect ratio (100).