Development and Performance Evaluation of Translucent Concrete Incorporating Activated Copper Tailings as Cementitious Material

This study reports a method for producing translucent concrete using alkali-activated copper tailings, aiming to advance the valorization of solid waste and the development of sustainable construction materials. Under optimal conditions—600 °C calcination, 10 wt% CaO, and a 1:2 water-to-solid ratio—the material achieved a maximum 28-day compressive strength of 52.7 MPa, accompanied by a significantly reduced setting time. Leaching tests indicated that Cu, Zn, Pb, and As concentrations were well below the standard limits, ensuring environmental safety. Further optimization revealed that incorporating 40 wt% cement and 2 wt% polypropylene fibers (1 mm in diameter) provided the best balance between light transmission and mechanical performance. Microstructural analyses (XRD and SEM) confirmed the formation of C–S–H and C–A–S–H gels with minor Ca(OH)2, which densified the matrix and enhanced strength. Despite these promising results, potential variations in the tailing composition and challenges associated with industrial-scale implementation must be considered. Overall, this work elucidates the hydration and solidification mechanisms of copper-tailing-based translucent concrete and highlights its potential for environmentally sustainable and functional construction materials.