Influence of the Recycled Concrete Aggregate Features on the Behavior of Eco-Efficient Mixtures

Abstract

The use of recycled concrete aggregate (RCA) has substantially grown over the last several decades. RCA is a composite material composed of original virgin aggregates (OVA) and residual mortar (RM); it has been found that accounting for RM as part of the total mortar volume in the design of RCA concrete can improve its mechanical and durability-related properties. Moreover, this impact might even be enhanced according to the RCA’s innate quality and features. Yet, there are currently very few quantitative data and evaluation protocols highlighting this influence, especially for eco-efficient RCA mixes. This work presents an experimental (i.e., chemical, mechanical, and nondestructive) characterization of 35-MPa RCA mixes incorporating distinct RCA qualities (i.e., 25, 35, and 45 MPa) and types (crushed limestone versus quartzite gravel) and proportioned through the equivalent volume (EV) method. Results indicate that RCA features may impact the overall performance of RCA concrete; however, RCA particles with distinct features may still be considered for structural applications whether or not a proper mix-design technique is adopted. Finally, the EV method seems to be a suitable strategy to design eco-efficient RCA concrete.