Israfil Kocaman, 1 Can Burak Sisman, 1,2 and Erhan Gezer 1 Effects of Coal Clinkers on Physical and Mechanical Properties of the Briquettes ABSTRACT: This study was carried out to investigate the effect of coal clinker used in briquette production on physical and mechanical properties of briquettes. To do this, seven briquette classes were formed by changing the volume of coal clinker and all-in aggregates and porous briquettes were produced for each class according to Turkish Codex no. 406 TS 406 and tested. Increasing ratio of coal clinker volume affected the compressive strength and water absorption of the briquettes negatively. As for the dimensional changes, bulk densities, losses due to freezing-thawing, and heat conductivity decreased and were af- fected positively. It was concluded that coal clinkers might be used in briquette production in certain ratio to make them profitable and lessen their adverse effects on the environment. KEYWORDS: briquette, coal clinkers, all-in aggregate, mechanical properties, physical properties Introduction Despite global warming and other environmental concerns regarding the use of fossil fuel in energy sector around the world, coal is still the mostly used fossil fuel. In fact, it is the fastest growing fossil fuel, especially in emerging economic powers like China and India. Its large reserves make it a popular candidate in energy sector of the global economy. Therefore, rather than ignoring the reality of using coal, the effective strategy should be to resolve the associated concerns to make it a better candidate in energy sector around the world. Managing the huge volume of coal clinkers, with minimal adverse environmental impact, is of great importance. The concept of an environmentally sustainable industrial development requires the reusing and/or recycling of a by-product within the same industry; or this by-product should be used as a raw material for another industry. Thus, the environmental footprints of these two industries could be mini- mized. For instance, the use of coal clinkers, a by-product of coal used in energy sector, in concrete production as aggregates could help lessen the adverse effects of coal clinkers on the environment around the globe. Coal, after burning, yields 20– 25 % of its weight as coal clinkers and ashes fly ash and bottom ash. These residues are generally considered an industrial solid waste, causing negative environmental foot- prints of energy sector using coal as a fossil fuel. The reuse or recycling of these residues is not widely practiced within the energy sector; these residues are not productively used as a raw material for another industrial sector. However, there is a potential of using such residues, as aggregates, in concrete production. Already, research literature appears on using, and testing the usefulness of, ashes in various construction materials and elements both in Turkey and around the world. Kula et al. 1 and Won et al. 2 investigated the effect of mixing fly and bottom ashes as aggregates on concrete properties like thermal conductivity, wetting and drying, freezing-thawing. They suggested that the use of ashes was suitable for the production of low strength construction elements. Similarly, Bertolini et al. 3 used ashes from burnt garbage as mineral additives in concrete and found that it improved puzzolanic properties and compressive strength while decreasing thermal conductivity. On the other hand, Bai et al. 4 stated that 30 % bottom ashes in the concrete as fine aggregates adversely affected concrete shrinking and compressive strength properties. Manuscript received November 1, 2007; accepted for publication May 7, 2008; published online June 2008. 1 Namik Kemal University,Agricultural Faculty, Farm Structure and Irrigation Department, TR 59030 Tekirdag, Turkey. 2 Corresponding author, e-mail: cbsisman@nku.edu.tr Journal of ASTM International, Vol. 5, No. 6 Paper ID JAI101513 Available online at www.astm.org Copyright © 2008 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.