Evaluation of environmental disturbance indicator using functional performance and life cycle assessment of ferrochrome waste concrete

Abstract

This paper reports on environmental disturbance indicators (EDI) using functional performance-based life cycle assessment (LCA) on concrete prepared using waste materials from the ferrochrome industry. The study is made on six concrete mixes with and without waste materials like ferrochrome ash (FCA) and air-cooled ferrochrome slag (ACFS). Lime-activated FCA is used for partial replacement of cement up to 47% and ACFS for total replacement of natural coarse aggregate. The study examines the sustainability of concrete mixes made with ferrochrome waste materials by LCA through the weighting schemes applied to five environmental impacts such as aquatic acidification (AA), carcinogens (CAR), global warming (GW), terrestrial ecotoxicity (TE) and respiratory inorganic (RI). The results of LCA based on the performance in terms of strength and durability indicated benefits in EDI of 46%. The robustness and independence of EDI results were checked through six different weighting schemes and the difference between these varied from 2.87 to 2.40%. The present work also includes the EDI-based study on the best-case and worst-case scenarios that describe the transportation of waste materials from the nearest and farthest plant. The results of such a study indicated that there is a difference of 4–11% between best-case and worst-case transportation scenarios. The contribution of various ingredients of concrete to the environment was checked through contribution analysis using OpenLCA software, where the results showed that cement is the top contributor. Lime and superplasticizer are the 2nd and 3rd contributors. Among the six concrete mixes made with and without ferrochrome waste materials, the normal concrete mix was found most unsustainable. There exists a good relationship between functional unit-based EDI values and scenario-based impact values. Results revealed that the concrete produced using ferrochrome waste materials have low EDI compared to conventional concrete.