The effects of engineering properties of waste tires into self compacting concretes

There have been more than 10 million waste tires in the world and it reaches about 300 thousand tons for our country. Degradation of waste tires in nature take very long time and leaving this waste into the landfills poses serious health hazards for both human health and the our habitat. Therefore, waste management for waste tires is necessary. Reuse of waste tires in the concrete production process is one of the recycling methods used. This method contributes to have lighter concrete materials and higher toughness and also contributes to elimination of waste. In this study, mechanically cut waste tires having 25, 50 and 75 mm in length were evaluated by replacing the volume of coarse aggregate in Self-Compacting Concrete (SCC). On the concrete specimens, having 5%, 10% and15% (by volume of coarse aggregate) of waste tires, unit weight, slump, J-ring, column segregation, water absorption, 28 day compressive strength, ultrasound pulse velocity and fracture energy experiments were performed. SEM (Electron Microscope) and EDS (Energy Dispersive Spectroscopy) analyzes of the samples were also investigated. In this study it was determined that use of rubber aggregate decreased fresh concrete unit weight, increase in rubber aggregate length was decreased the passing ability of the mix between reinforcing bars, dry unit weight of the specimens decreased, adding 10% rubber aggregate increased the compressive strength of the specimens and based on the ultrasonic pulse velocity results good grade concrete quality can be obtained. As a result, it was observed that optimum results were obtained from self-consolidating concretes having 25 mm length and 10% volume fraction.