A review of corncob-based building materials as a sustainable solution for the building and construction industry

The building and construction industry faces mounting pressure to adopt sustainable practices and materials due to its significant environmental impacts. Corncob (CC), a by-product of the corn industry, has shown great potential as a sustainable and versatile building material as contained in literature. Although no study has categorised the different repurposing applications of CC in building and construction. This systematic review investigates the potential of corncob, an abundant agricultural by-product, as a sustainable building material. Through analysis of 33 peer-reviewed studies from 2000 to 2023, it examined the diverse applications and evolving research trends of corncob in the building and construction industry. Key findings highlight corncob's global availability, low carbon footprint, and favourable properties for building applications. The review reveals nine distinct uses, including thermal/acoustic insulation, soil stabilization, fillers, cement replacement, aggregates, composite materials, particleboard production, and alkali-activated binders. Emerging research focuses on corncob ash as a supplementary cementitious material, with optimal cement replacement levels of 5–30 % by weight identified. Corncob-based materials demonstrate enhanced fire resistance, chemical durability, thermal insulation, and long-term strength development, though compressive strength remains a limitation for structural applications. The study concludes that corncob shows significant promise for advancing environmental sustainability in construction, particularly for non-structural and insulation applications. However, further research is needed to optimize material properties, standardize production methods, and evaluate full lifecycle impacts to enable widespread commercial adoption. This review provides a foundation for future investigations into innovative, low-carbon building materials derived from agricultural residues.