A Comprehensive Review on the Properties, Environmental Concerns, and Engineering Applications of Brick Kiln Dust and Pond Ash

Brick kiln dust and pond ash are two significant industrial by-products generated from brick manufacturing units and coal-based thermal power plants, respectively. Owing to their abundant availability and varied physico-chemical characteristics, these materials have gained increasing attention in geotechnical and construction engineering. This review synthesizes published research on their physical, chemical, mineralogical, microstructural, and engineering behaviors to evaluate their suitability for sustainable material substitution. Brick kiln dust is predominantly composed of silt-sized particles, exhibits negligible plasticity, and contains high proportions of silica, alumina, and iron oxides—characteristics that align with pozzolanic materials. However, its potential environmental toxicity necessitates careful assessment before field application. Pond ash, on the other hand, is known for its lightweight and porous structure, influencing the compaction characteristics, strength properties, and stabilization performance of soils. Research indicates that although pond ash alone may reduce unconfined compressive strength, synergistic use with cement, rice husk ash, or fibers substantially enhances soil performance. The review also highlights the potential of these materials in wastewater treatment, brick manufacturing, and ground improvement. This study underscores the importance of proper characterization and engineered utilization to promote sustainable practices in civil engineering applications.