Abstract: Tailings, a byproduct of mineral processing, pose a significant global environmental issue. These waste materials accumulate and contaminate the surrounding areas with heavy metals. To explore the possibility of reusing tailings in concrete, we selected copper mine tailings as a partial substitute for cement in concrete preparation, and performed tests on concrete samples to assess the compressive strength, resistance to chloride ion penetration, Toxicity Characteristic Leaching Procedure (TCLP), and X-ray diffraction (XRD). The findings revealed a substantial loss of early compressive strength, and also a decline of compressive strength with higher replacement rates of copper tailings. At the age of 28 days, compared to ordinary concrete, samples containing 10%-40% copper mine tailings exhibited improved resistance to chloride ion penetration, whereas those with 50%-60% copper mine tailings displayed a decrease. However, at the age of 90 days, the resistance to chloride ion penetration of all tailings samples improved. This improvement can be attributed to the participation of copper mine tailings in cement reactions, resulting in the stabilization of metals through metal hydroxide precipitation or their presence within cement crystals. Moreover, the leaching rate of heavy metals in all copper mine tailings samples was within standard limit.

Key words: copper mine tailings, compressive strength, chloride ion penetration, TCLP, XRD