Use of Waste Ferrochrome Slag as a Sustainable Building Material for Extreme Environments

Ferrochrome slag is an industrial by-product material extracted during the production process of ferrochrome alloy, which is mostly used in the stainless steel industry. Large quantities of ferrochrome slag are generated annually from the steel companies in the Sultanate of Oman. The vast majority of the quantities are not used in any application and are disposed of without being reused, posing a threat to the local environment. There has been an increasing emphasis in recent years on the use of different waste materials as construction materials, which may help to alleviate environmental and ecological challenges. The physical, mechanical, chemical and thermal properties of ferrochrome slag (FCS) are favorable to be used in concrete for extreme environments such as high temperature and corrosive environments. In this study, the effect of using ferrochrome slag as a substitute for natural fine and coarse aggregates (incremental range from 25% to 100%) on the strength of concrete at elevated temperatures (ranging from 200°C to 1000°C with 200°C intervals) was investigated. Acid resistance of FCS concrete was also investigated. It is found that the inclusion of FCS enhances the compressive strength of the concrete. The thermal properties of FCS aggregate positively affect the fire resistance of the FCS concrete. The FCS concrete shows better performance in an aggressive environment than conventional concrete. Therefore, waste ferrochrome slag may be an alternative option to be used as green coarse and fine aggregates in the production of concrete.