Effect of High Percentages of Coated Recycled Aggregates on the Flexural Behavior of Reinforced Concrete Beams

Currently, the use of recycled aggregates (RA) in new concrete is allowed by several international regulations, although their replacement is limited to low percentages of the coarse fraction. In order to increase the percentage of RA, several authors have studied different processes to improve the microstructure of its surface. Therefore, it is necessary to analyze whether the current standards simulate the structural behavior of concretes with high percentages of RA. For this purpose, beams with 0%, 50% and 100% RA replacement coated with recycled binder paste (RBP) were made and their behavior was compared with the equations of the Eurocode 2 and ACI 318-19 code. As a result, we found that when 100% coated RA was used, the reduction in compressive strength was only 12.73%, with similar cracking patterns observed in RA beams across all series. In addition, the load capacity of the beams with RA was higher than the theoretical values provided by the codes. Finally, the experimental critical deflection was higher than that calculated by the code equations. Thus, it is recommended that these higher deflections be taken into account at the time of design.