Recycled Self-Compacting Concrete: Mechanical Behavior and Durability

Increasing sustainability is currently one of the main objectives of the construction sector. One of the most widespread sustainable practices to reach this goal is the recycling of industrial residues within concrete mixes. What began as a practice to produce low-quality concrete has now spread, for example, to Self-Compacting Concrete (SCC), which has a high flowability in the fresh state. Recycled Concrete Aggregate (RCA) is a waste that can be used to develop SCC of good mechanical performance. RCA produced from the crushing of rejected precast components for the prefabricated concrete industry is assessed in this study. It was demonstrated that the addition of 100 % coarse RCA and 50 % fine RCA contributed to the production of an SCC with adequate flowability and an optimal mechanical and durability behavior. To do so, the design of the mixture, its flowability, its strength behavior at different curing ages and its performance in freeze/thaw, moist/dry and sulfate-attack tests are discussed. The study is complemented by analyzing the interaction of RCA with different natural fine aggregates, such as siliceous or limestone sand. It is concluded that the SCC developed with large amounts of RCA was of sufficient strength and durability for general usage.