In parallel with the increase in vehicle sales worldwide, waste tires are becoming an increasing problem. The storage and disposal of these waste tires are critical environmental problems. Re-using these wastes in different areas instead of being disposed of is vital in preventing environmental pollution and creating new low-cost products. From this motivation, this paper investigates the properties of traditional reinforced-concrete beam with recycled steel wires (RSWT) obtained from the waste tires. RSWT were added to reinforced-concrete beam between 1% and 3% by weight with an increment of 1%. In total, 9 cubes, 12 cylinders and 12 reinforced-concrete beams were cast and tested to obtain the compressive, splitting tensile and flexural strengths, respectively. RSWT added to the concrete by 1%, 2% and 3% increased the compressive strength by 17.2%, 30.8% and 46.4%, respectively, compared to the reference concrete. In split tensile strength, 14.4%, 25.1% and 36.7% increases were observed, respectively. This showed that there was an effective increase in the compressive and tensile strength of concrete with the increase of fiber content. Although the effect of fiber content in samples with high stirrup spacing (27 cm) provides significant benefit in improving the beam behavior, the effect of fibers was more limited as the stirrup spacing decreased (20 cm and 16 cm). An approximation of over 91% was obtained between the analytical calculations and the experimental results. This shows that the analytical calculations given in the standards can be used for new experimental studies.
In this study, the impacts of different proportions of tension reinforcement and waste lathe scraps on the failure and bending behavior of reinforced concrete beams (RCBs) are clearly detected considering empirical tests. Firstly, material strength and consistency test and then ½ scaled beam test have been carried out. For this purpose, a total of 12 specimens were produced in the laboratory and then tested to examine the failure mechanism under flexure. Two variables have been selected in creating text matrix. These are the longitudinal tension reinforcement ratio in beams (three different level) and volumetric ratio of waste lathe scraps (four different level: 0%, 1%, 2% and 3%). The produced simply supported beams were subjected to a two-point bending test. To prevent shear failure, sufficient stirrups have been used. Thus, a change in the bending behavior was observed during each test. With the addition of 1%, 2% and 3% waste lathe scraps, compressive strength escalated by 11.2%, 21.7% and 32.5%, respectively, compared to concrete without waste. According to slump test results, as the waste lathe scraps proportion in the concrete mixture is increased, the concrete consistency diminishes. Apart from the material tests, the following results were obtained from the tests performed on the beams. It is detected that with the addition of lathe waste, the mechanical features of beams improved. It is observed that different proportions of tension reinforcement and waste lathe scraps had different failure and bending impacts on the RCBs. While there was no significant change in stiffness and strength, ductility increased considerably with the addition of lathe waste.
21 September 2023 in Journal of Building Engineering