Flexural Behavior of Rubber-Filled Reinforced Concrete Beams Strengthening with CFRP Sheets

Civil Engineering Department, Al-Nahrain University, Baghdad, Iraq

^a* Corresponding author adnanalqaisy72@gmail.com
^b ahmed.s.ali@nahrainuniv.edu.iq

Abstract

Although there are many advantages to using rubber to produce reinforced concrete substrates, there are still few applications for rubberized concrete substrates like beams, where the mechanical properties of rubber-infused concrete, such as flexural strength, begin to decline. On the other hand, flexural strengthening constitutes a sizeable portion of the structural uses for externally carbon fiber reinforced polymer (CFRP) sheets when used to strengthen reinforced concrete beams. For this study's rubberized concrete beams, the externally adhered (CFRP) sheets were used as a substitute for the loss of flexural strength. The study's reinforced concrete beams were split into two groups, each consisting of three beams. The first group's concrete mixture was included as a filler (5) % of the cement weight in the form of waste tire rubber with a size not more than (0.075) mm. Any group of concrete beams always had a first beam without any external reinforcement, a second beam with one layer, and a third beam with two layers of (CFRP) sheet. The results indicate that the load at the first crack increases to be equal to that of the un-rubberized beam when the rubberized reinforced concrete beam is strengthened with one layer of (CFRP) sheets, and it increases by (20%) when reinforced with two layers of (CFRP) sheets. When reinforced with one or two layers, the load at failure rises by 23.58 and 42.75 percent, respectively. The first crack deflection rises by 88.11 and 120.24 percent, while the failure deflection falls by 2.97 and 6.01 percent, respectively. On the (load-deflection) curve, the deflection decreases at symmetrical loads.