Novel LCA-centric mix design approach for alkali-activated EAF slag with hybrid optimization techniques

Area of Science:

• Materials Science
• Environmental Science
• Civil Engineering

Background:

• Ordinary portland cement (OPC) production has significant environmental impacts.
• Alkali-activated materials (AAMs) offer sustainable alternatives using industrial byproducts.
• Optimizing AAM mix design is crucial for balancing performance and environmental benefits.

Purpose of the Study:

• To develop and optimize alkali-activated materials (AAMs) using electric arc furnace slag (EAFS) and fly ash.
• To evaluate the environmental performance of AAMs using life cycle assessment (LCA).
• To determine the optimal AAM mix design for enhanced sustainability and performance.

Main Methods:

• Life Cycle Assessment (LCA) with ReCiPe midpoint methodology and mass/economic allocation.
• Taguchi-based hybrid optimization integrating Gray Relational Analysis (GRA) and Analytical Hierarchical Process (AHP).
• Evaluation of fresh properties, mechanical performance, durability, and sustainability indices.

Main Results:

• Global warming potential and terrestrial ecotoxicity were key environmental impact categories.
• Mixes with at least 50% EAFS demonstrated superior sustainability over OPC.
• A blend of 75% EAFS and 25% fly ash achieved the optimal balance of performance and environmental impact.

Conclusions:

• AAMs, particularly those with high EAFS content, are viable sustainable alternatives to OPC.
• The proposed LCA-centric optimization approach effectively guides the development of eco-friendly construction materials.
• The 75% EAFS and 25% fly ash mix represents a promising direction for sustainable construction practices.