Recycling of Coal Ash in Production of Low Density Masonry Unit

Coal ash is a residue that is created when coal is burned by power plants to produce electricity. Coal ash is one of the largest types of industrial waste and causes environmental pollution. On the other hand, coal ash is potentially a valuable source of minerals, including SiO₂, Al₂O₃, CaO, MgO, Fe₂O₃, Na₂O and K₂O. This study aims to recycle the coal ash in production of low density masonry unit. Coal ash was characterized by chemical and X-ray diffraction analyses. The batches containing different ratios of coal ash and a brick making clay were prepared and shaped by cold pressing. The pressed samples were fired at 1050 and 1100°C. The physical properties such as water absorption, apparent porosity, linear shrinkage, and bulk density were determined. Microstructural observations were performed by using scanning electron microscopy. Based on the technological characteristics; it was observed that low density masonry units can be produced by using coal ash. This study supports the responsible recycling of coal ash by distinguishing beneficial use from disposal.