Normal- and high-strength concretes incorporating air-cooled blast furnace slag coarse aggregates: Effect of slag size and content on the behavior

Abstract Over the past two decades, air-cooled blast furnace slag aggregates have been considered as an alternative coarse aggregate material in concrete toward attaining resource sustainability in the construction industry. It is now recognized that the application of slag aggregates to form recycled slag aggregate concrete (SAC) is a highly promising technology to reduce environmental impact of both the slag waste and concrete. This paper presents the first experimental study on mechanical properties of SAC prepared with coarse slag aggregates of different sizes. Normal- and high-strength SACs were manufactured with two different grades of slag aggregates. Tests were undertaken to establish the compressive strength, elastic modulus, splitting tensile strength, workability, and fresh and hardened density of each batch. The results show that the investigated mechanical properties of concretes with larger slag aggregates are higher than those of the companion mixes with smaller aggregates. Results also show that the mechanical properties of SACs decrease with an increase in the slag aggregate content. Although it has been shown that SACs exhibit inferior properties compared to those of natural aggregate concretes, this difference is not excessive in normal-strength SACs with up to 100% slag aggregates and high-strength SACs with up to 50% slag aggregates, suggesting that the technique investigated in this study can provide an attractive avenue for value-added use of air-cooled blast furnace slag.