Effect of Galvanized Iron Fiber on Bond Strength of Recycled Aggregate Concrete

Recycled coarse aggregate (RCA) is being encouraged to be used in concrete to protect natural resources and manage structural demolition debris. On the other hand, a strong bond between concrete and reinforcing bars ensures the safety and durability of any structure. However, recycled aggregate concrete (RAC) has relatively inferior properties to natural aggregate concrete (NAC), which can be mitigated through fiber application. Thus, this study investigates the mechanical properties and bond behavior of galvanized iron fiber (GIF)-reinforced recycled aggregate concrete. Variables in this study are the percentages of GIF (0, 0.25, and 0.5%), rebars of diameter (D) variations (16 and 20 mm), and the embedded lengths (8D and 12D). Two variations of RCA are used: 0 and 50%. The results disclose that as RCA increases, mechanical qualities degrade. However, using GIF has an advantageous impact on these characteristics. While compressive strength exhibits no direct relation with the amount of GIF, tensile strength shows a proportional relation. GIF increases the bond strength by up to 46%, especially with 0.25% GIF. Cylindrical specimens reinforced with 16 mm bars having embedded lengths of 8D demonstrate pull-out failure. For the other cases, the failure is primarily concrete. This study will decisively promote the use of RCA and GIF to improve the bond between concrete and rebars.