Bond Behavior between Recycled Concrete Containing CDW and Different Types of Steel Bars

The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete, which allows the internal forces to be transferred to the reinforcement during the process of loading the structural elements. The modification of the concrete composition, with the introduction of recycled aggregate from construction and demolition waste (CDW), affects the steel-concrete interface and can modify the bonding stress, which is also influenced by the type and diameter of the bar used. In this work, the influence of the recycled fine aggregate (RFA) and types of steel bar on the steel-concrete bond was experimentally evaluated using the pullout test. Conventional concrete and recycled concrete, with RFA replacement level of 25%, were produced. Two types of steel rebars (i.e.,plain and deformed) with diameters of 10.0 and 16.0 mm were considered in this paper. The results indicate a reduction in the adhesion stress with the introduction of recycled aggregate, but this trend is influenced by the diameter of the bar used. The use of ribbed bars modifies the stress bonslip behavior, with an increase in the average bond strength, which is also observed with the reduction of the diameter of the bar