Cement mixtures containing copper tailings as an additive: durability properties

The effects of copper tailings, as an additive, on some durability properties of cement mixtures were investigated. In each mixture, the copper tailings additions were 0, 5 and 10 wt%. Compared to the control samples, copper tailings blended pastes showed superior performance against autoclave expansion, while insignificant decreases in sulphate resistance of mortars were seen. Copper tailings slightly increased the water absorption and total permeable voids of concretes. However, the compressive and flexural strengths of the blended concretes were higher than those of the control samples. Improved resistance to acid attack and chloride penetration with increasing copper tailings content were also found. Results showed that the ASTM C 1202 rapid chloride permeability test may not be a valid indicator of chloride migration in mixtures containing conductive copper tailings. It is suggested that copper tailings can potentially enhance the durability properties of cement-based materials.