Beyond Burnt Bricks: Reassessing Otukpo Soil for Sustainable Construction Applications

The Otukpo Burnt Brick Factory has remained dormant for thirty years, despite several attempts by the government to revive it. Given the region’s rich clay deposits and the growing demand for sustainable, affordable construction materials, in this study, we investigate Otukpo soil’s suitability for alternative uses such as uncalcined brick production and its pozzolanic potential for use as a supplementary cementitious material (SCM). While the Unconfined Compressive Strength (UCS) results, which ranged from 5 to 10% for the cement-stabilized samples, fell short of the required threshold for building walls, the soil achieved cube strengths of up to 1.1 N/mm² at 14 days, demonstrating a promising strength performance early on. In contrast, stabilization with 5-10% NaOH provided less than half the strength achieved with an equivalent cement content, indicating that standalone alkali activation has limited potential for improving Otukpo soil’s mechanical properties. However, the high total SiO₂, Al₂O₃, and Fe₂O₃ content (> 70%) strongly supports the material’s potential as an SCM in blended cement systems. These findings highlight the importance of continued research into low-energy, uncalcined/minimally processed brick production and cementitious uses of Otukpo soil, alongside the establishment of standardized practices. Together, these efforts could reveal the intrinsic value of this locally abundant material in compensating for regional disparities in brick supply while fostering job creation through decentralized, community-driven industries.