The main objective of this study is to determine the usability of the straw and reed residues, which are generated during the bleached kraft pulp production, in constructional clay brick production. Due to the environmental regulations, demand for the high insulation capacity bricks is increasing. The thermal conductivity is a decisive factor for the heat-engineering
concept of thermal insulating material. Apart from the molecular composition of a material, it also depends on the air pore content and its structure.For building practice therefore the body density determines the thermal conductivity [5]. One of the most conventional ways to increase the insulation capacity of the brick is to generate porosity in fired clay body. Adding porosifers to the ceramic body can form pores. Most frequently used pore formers, which are used in clay brick
manufacturing can be classified into two groups. Sawdust, styropor, paper sludge, coal and coke are some examples for the organic pore formers. Perlite, diatomite, lime flour, pumice and vermiculite are examplesfor the inorganic (mineral) type pore formers. Organic pore formersare generally cheaper than inorganicsand also when they are burnt; it gives
oversupply of heat to the firing furnace. However, CO2 emission is the main drawback of the organic pore formers. Inorganic pore formers have less environmental problemsbut they may change the plasticity of the clay system negatively and may increase the water demand for the plasticity [6–9]. Organic process residues are extensively used as a pore former in brick industry. Paper making sludge or residues is one of the bestknown organic pore-forming residues. It contains both organic materialsand inorganicssuch as lime, kaolin or bentonite etc. [10].It should be mentioned that papermaking residues, because of the high fiber content, have now become indispensable in many clay products for the
stabilization of drying behaviour, so that apart from its pore forming action, it may also be regarded as a production auxiliary [11]. However, bleached Kraft pulp production, which isearly stage of paper production, also generates an important amount of organic residue, which contains short cellulose fibers without any mineral content, and this has not been utilized sufficiently yet.