Experimental investigation on the effect of using crumb rubber and steel fibers on the structural behavior of reinforced concrete beams

• Published in: Construction & building materials 2020-08, Vol.252, p.119078, Article 119078
• Main Authors: Eisa, Ahmed S., Elshazli, Mohamed T., Nawar, Mahmoud T.
• Format: Article
• Language: English
• Subjects: Crumb rubber; Mechanical properties; Recycled tires; Reinforced concrete; Steel fibers
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2020.119078

•Experimentally study the effect of crumb rubber and steel fibers on RC beams.•Incorporating 10%, rubber improved ductility and toughness of concrete mixtures.•Combining 1% steel fibers and 10%, rubber improved the performance of RC beams. The effect of combination between crumb rubber and steel fibers on the behavior of reinforced concrete beams under static loads was investigated in this study. Crumb rubber, ranging in size between 2 mm and 3 mm, was produced from waste tires. Then, it was incorporated into plain concrete (PC) and steel fiber concrete (SFC) mixes by partially replacing of fine aggregates at different percentages by weight (5%, 10%, 15%, and 20%). Steel fibers volume fraction was kept constant at 1%. An extensive experimental program of 130 samples was conducted in two stages. The first stage included compressive test, splitting tensile test, and flexural test, in order to investigate the mechanical properties of the designed concrete mixtures. The second stage was carried out to investigate the static behavior of reinforced concrete beams, using the designed concrete mixtures, under four-points flexural test. Test results showed that using crumb rubber as partial replacement of fine aggregates by 5% and 10% show an acceptable performance of reinforced concrete beams. Using steel fibers with rubberized concrete with percentages of rubber over than 10%, improved the performance and the toughness of these mixtures.