Synergism of life cycle assessment (LCA) and sustainable development goals (SDGs) framework for best selection of sludge-based concrete scenarios

Abstract

This study establishes a synergetic interaction between life cycle assessment (LCA) and sustainable development goals (SDGs) to evaluate the environmental impacts of sludge utilization as a partial substitute for cement and address the socio-economic dimensions of sludge valorization in concrete manufacturing. Different concrete mixtures were prepared using 5–20% mass ratios of raw sludge (RS) and thermally activated alum sludge (TAAS) as partial replacements of ordinary Portland cement (OPC). The Ecoinvent-3 and Agri-footprint databases, with the SimaPro 7.1 software, are used to define the environmental impact categories of these alternatives and identify the best sludge/concrete management scenario. The 5% RS and 15% TAAS concrete samples obeyed the compression strength requirement (25 MPa) as justified by the blends’ pozzolanic properties, fine particle size, and amorphous silica structure. The LCA findings revealed that 5% RS was the best choice due to the improved midpoint and endpoint impact categories, reducing the global warming potential by 75% compared with the OPC-based concrete scenario. This finding was supported by the outcomes of SDG scoring, where 5% RS exhibited the best sludge recycling approach because it attempted to minimize the amount of waste disposed to the landfills and reduce the associated greenhouse gas emissions. Because the assigned socio-enviro-economic indicators maintained sustainable concrete industrialization from sludge management, further studies should encourage stakeholders and policymakers to utilize the developed LCA/SDG synergetic tool for waste recycling in building materials.