The Impacts of Recycled Concrete Aggregates and Fiber Architecture on the Mechanical Performance of Recycled Aggregate Concrete Reinforced With Steel Fibers: Role of Meso-Scale Toughening Mechanisms

Recycling end-of-life concrete as an aggregate source can promote sustainability in the construction industry. However, this is prohibited by inherent defects of recycled concrete aggregates (RCAs). Therefore, current study delves into influences of utilizing RCA with different sizes and reinforcing fiber with different architectures on the mechanical and cracking behavior of recycled aggregate concrete (RAC). It is observed that RAC's compressive strength exacerbates with rising substitution levels in an almost linear decreasing trend. However, fine RAC exhibited better compressive performance than the coarse one. Reinforcing steel fibers improved the mechanical strengths of RAC. However, regardless of fiber content, utilizing 3D spiral-fiber resulted in better performance in different mechanical strengths than 1D straight-fiber. In addition, meso-scale toughening mechanisms that can be activated in RAC and can enhance its performance were discussed. The findings of this study provide technical support for introducing “spiral-fiber reinforced fine RAC” as crack-resistance sustainable cement-based material.