Investigating the Effect of Steel Wire and Carbon Black from Worn Out Tyre on the Strength of Concrete

Technology in concrete is rapidly developing to improve the quality and properties of concrete. One of the many recycled materials is worn-out tyres. Currently, the use of tires is very widespread considering the use of vehicles that increase from time to time. Piles of discarded tires can cause a lot of damage to the environment. So, by using steel wire waste (SWW) as new fiber reinforcement in concrete and with the combination with carbon black (CB), it is hoped that, by doing this, not only it could improve the quality of concrete, but also preserves the environment. Therefore, the objective of this research was, to identify the properties of fresh concrete with the addition of SWW and CB, and also to investigate the physical and mechanical properties of hardened concrete, incorporating of SWW as additional fiber reinforcement and CB. For fresh concrete, workability using a slump test was conducted. Several tests were carried out on the properties of hardened concrete. Among them were compressive strength, flexural strength, splitting tensile strength, and water absorption. The physical appearance of the concrete has also been examined and recorded. There are four batches of concrete which consist of one control batch and three batches of concrete with various weights of SWW which are in the portion of 300 g, 600 g, and 900 g, and the weight of CB is maintained at 300 g for all batches. For workability, all concrete batches with the addition of SWW and CB show acceptable workability. For the case of the density of fresh concrete, samples containing 900 g addition of SWW have the highest density which was 2520 kg/m³, as expected. Results for water absorption show that the lowest value is contributed by the control sample which was 7.6%. For compressive and flexural strength, 300 g addition of SWW has the highest value which was 28.52 MPa for compressive strength and 7.52 MPa for flexural strength. Lastly, for splitting tensile strength, the highest value was also obtained when 300 g addition of SW was added which was 5.4 MPa. To conclude, SWW and CB can be added to concrete to obtain comparable strength of concrete. However, some modifications could be made to both recycle materials to improve concrete performance.