Feasibility of incorporating recycled fine aggregate in high performance green lightweight engineered cementitious composites

The high-quality reutilization of recycled concrete aggregate, particularly the valorization of recycled fine aggregate (RFA) that exhibits inherent defects, is of great importance to mitigate environmental concerns associated with aggregate depletion and waste concrete disposition. In this study, RFA and industrial wastes were successfully used to develop high performance green lightweight engineered cementitious composites (HPGLW-ECC) through proper tailoring of the components. The designed eco-friendly material exhibiting a density of 1733 kg/m3, tensile strength up to 6.42 MPa and tensile strain capacity to 7.46% features impressive mechanical properties. It is remarked that the incorporation of 0–1 mm RFA contributes to the continuous grading of HPGLW-ECC and minimizes the gaps between the particles, which improves the overall compactness of the material. The high roughness of RFA favors the interlocking effect between fiber and matrix and contributes to the development of fiber bridging capacity. Moreover, the self-cementing of RFA further densifies the microstructure of HPGLW-ECC. The enhancement effects of 0–1 mm RFA on the mechanical performance of HPGLW-ECC were characterized by the refinement of microstructural pores as well as by the failure morphology features of fiber and matrix.