Experimental Investigations on the Properties of Coal-Ash Brick Units as Green Building Materials

In India, production of electricity by thermal power plants accounts for more than 50% of the total electricity generated. While doing so, the thermal power plants produce about 117 million tons per year of coal ash as waste materials. Improper disposal of this ash poses a threat to the environment. It requires allocation of vast land area for dumping/storing and it pollutes the land. Ash generated in thermal power plants falls into two categories, namely, fly ash and pond ash. One of the ways to minimize the harmful effects due to unsafe disposal of ash on the environment is to utilize the ash in the construction industry as an admixture in brick making, cement manufacture, etc. Moreover, in the conventional brick making, a precious natural soil resource is overexploited. One of the essential requirements of green building is to use environmentally friendly building materials as well as to reuse/ recycle industrial waste products like fly ash and pond ash. If the fly ash and pond ash are used optimally by replacing clay in the brick-manufacturing industry, then this waste material can be treated as greener material. This will also reduce the pressure on the excavation of soil. Besides energy-saving methodologies, green building involves the application of all technologies and using of materials without affecting the natural resources. In this investigation, an attempt was made to devise ways for the optimal use of pond ash in manufacturing coal-ash bricks. This article presents the experimental results for coal ash brick made up of pond ash with fly ash, lime, gypsum, and stone dust. The fundamental strength and durability tests were conducted to evaluate the basic properties of bricks. An energy dispersive x-ray diffraction study and a scanning electron microscope (SEM) study were carried out for elemental analysis and to analyze the chemical composition of the abovementioned materials.