Abstract
Mixing coal mine overburden with sodium silicate and cement, for manufacturing bricks was studied with the objective of converting the coal mine overburden waste into value-added products. Bricks were prepared using different compositions of coal mine overburden with proportions of sodium silicate and Ordinary Portland Cement (OPC), in cuboid mould (9″ X 5″X 3″). Bricks were air dried for 24 hours, placed in oven for 115 ± 10 °C for 24 hours. Characterization of tailings and manufactured bricks were done. Mechanical properties such as compressive strength (CS), water absorption (WA), loss on ignition (LoI) and efflorescence were measured. The maximum CS of 9.5 N/mm2 was recorded for brick having overburden to cement ratio of 8:2. However, for making it more economical the ratio of 9:1 was considered and this compares very well cost with full filed the Indian standard (IS): 3495 (Part 1) (1992) of bricks. The results also indicated that the overburden percentage in the bricks affect their mechanical properties. The WA rates of the manufactured bricks are low compared to standard conventional clay bricks, and the same varies with process parameters. The low capillary pore may deter the formation of efflorescence. The process, with standardized parameters, may be commercially adapted, and large quantities of coal mine overburden may be put to use in making bricks. Thus, the process technology observed in this paper can potentially convert the huge amount of environmentally hazardous waste into value added product. Coal mine overburden may materialize as a sustainable supplement to conventional clay, use of which in brick making is totally restricted. The finding also usher a new area of research.
Experimental Characterization of Solid Clay Bricks: Correlations Among Mechanical Properties