Utilization of copper blasting grit waste as a construction material

The present study investigates the possibility of recycling a sand blasting grit (copper slag) generated from a major industry in Bahrain. The amount of grit waste arising is estimated to be around 6,000 tons per year, with approximately 30 - 40,000 tons stockpiled on site at the present. The physical and chemical analysis of the waste were studied. Mortar cubes 2 inches × 2 inches (25.4 × 25.4 mm) were casted of grit and an ordinary Portland cement at ratios by weight of 1:1 (500 g/kg and 500 g/kg), 1:3 (250 g/kg and 750 g/kg), and 1:4 (200 g/kg and 800 g/kg) of cement to grit, and a water/cement ratio by weight of 0.5 (500 g/kg). The Compressive strength at 3, 7, and 28 days was determined. At 28 days strength values of 35, 34, and 33 N/mm2 were obtained for mixes with ratios by weight of, 1:1, 1:3, and 1:4, respectively. Also concrete cubes of 150 mm × 150 mm were casted at different water/cement ratios. The compressive strengths were determined at 3, 7, and 28 days, respectively. The grit was also incorporated in the manufacture of 15 cm concrete blocks. The results indicated an average compressive strength value of 12 N/mm2 which was within the Bahrain specification for precast concrete blocks. The results of the investigation suggested that copper slag grit can be used as a replacement of marine sand used in mortars for concrete blockworks.