Recycled coarse aggregates (RG) commonly exhibit high porosity and internal microcracks, which often limit their use in cementitious composites. In this study, these inherent characteristics were utilized to develop a functionalized recycled aggregate for conductive and piezoresistive cementitious materials. A conductive coating composed of carbon fiber and graphite was applied to the RG surface, taking advantage of its high water absorption and rough texture to promote slurry penetration, coating adhesion, and interfacial bonding. By concentrating the conductive phase on the aggregate surface, this strategy avoids dispersing conductive fillers throughout the cement matrix and provides a new route for integrating recycled aggregates with sensing capability. After functionalization, the volume resistivity of RG decreased from 210.1 Ω·m to 48.6 Ω·m, while the crushing index decreased from 13.1% to 11.9%, indicating improvements in both electrical conductivity and aggregate integrity. Acoustic emission analysis further showed delayed damage evolution during loading, with the final damage variable decreasing from 7.6% to 6.1%. When incorporated into cementitious composites, the carbon fiber–graphite cement slurry coated recycled aggregate concrete without matrix fillers (CGCRG‐0), which contains no additional conductive fillers in the matrix, achieved a volume resistivity of 49.6 Ω·m. Although this value was close to that of the RG‐125 mixture at 57.6 Ω·m, CGCRG‐0 exhibited a more stable piezoresistive response, with signal deviation reduced from 10.96% to 4.54%. In addition, the composite maintained a compressive strength of 43.6 MPa and reduced raw material cost by 12.2%. This work establishes a pathway for upgrading construction waste into materials for precision sensing. It highlights the potential of functionalized recycled aggregates in low‐cost cementitious sensing applications.
He et al. (Thu,) studied this question.