The integration of industrial by-products into civil engineering practices offers a dual advantage: efficient waste management and the preservation of natural resources. This study aligns with national objectives to develop resilient, sustainable, and environmentally friendly infrastructure. Locally sourced industrial by-products, specifically grit blast and ferrochrome slag, were utilized as substitutes for fine and coarse aggregates in the base course of flexible pavements. A series of mix designs were developed by varying the proportions of by-products and natural materials. Key properties, including gradation, plasticity, compaction, California Bearing Ratio (CBR), and leaching behavior, were systematically evaluated. The findings revealed that blends containing up to 70% by-products, combined with natural materials, met the gradation, compaction, and CBR requirements for Class B aggregate base courses. Furthermore, leachate analysis confirmed minimal heavy metal content, validating the environmental suitability of these by-products for pavement applications. This research underscores the local potential of green technologies in advancing sustainable infrastructure solutions.