The Effect of Adding Nickel Processing Tailings to Concrete Mixtures on a Laboratory Scale

One of the stages in mining is processing. At the processing stage. minerals are processed to produce products with higher mineral concentrations. This process has by-products called tailings. The Indonesian mining industry as one of the world's nickel producers cannot be separated from this issue. The large nickel production also has an impact on the large tailings production. These tailings are generally just stockpiled without further use. This study aims to provide an understanding of the strength of the material resulting from the addition of tailings to the concrete mixture. Five variations of the material were made by mixing tailings with ratios of 0%, 20%, 40%, 50%, and 60% in the concrete mix. Physical and mechanical properties testing was carried out to obtain the rock strength value from the concrete sample. During this research, the parameters of UCS, Young's Modulus, and Poisson's Ratio were used as indicators of rock strength. Based on the tests that have been carried out, the addition of tailings to the concrete mix generally weakens the strength of the concrete. However, there is a trend of increasing rock strength at a mixture ratio of 60% where the UCS value is 1.324 MPa and Young's modulus is 0.584. Furthermore, porosity and degree of saturation are considered to have a role in these rock strength parameters. This is indicated by the degree of saturation of the 60% ratio, which is 18.8 with an increase in Young's Modulus and UCS. Based on these results, it can be concluded that tailings can be further utilized in concrete mixtures so that their availability in the field can be converted and reduced. Finally, other parameters of the mixing ratio can be performed to complement the weaknesses in this study.