Efficient Recovery of Solid Waste Units as Substitutes for Raw Materials in Clay Bricks

The advent of new materials and technologies in building materials has changed the way of building. New lighter materials with easier application methods and improved mechanical behaviors, have become necessary for the market. Moreover, the new environmental policy (2022) aims to transform the waste management into sustainable materials management to ensure the long-term protection and improvement of the environment. For the brick and tile industry, raw materials and the additives that compose the product mixture seem to be a key factor in this direction. Furthermore, every product type (solid or perforated brick) requires different additives to achieve the properties that are postulated by the international standards. For the study, the wide range of additives that were used have been assorted into three (3) categories: the inert materials, the lightweight materials, and the industrial remains. Totally, eight (8) different materials were used as additives into ceramic mass, in different proportions each time. Almost all additives used for this research were pore-forming agents. These burn out almost completely before reaching the full-fire temperature, and do not change the fired body. As a result of additives burnt out, the necessary pore volume is formed in the fired brick body, which, if combined with an appropriate percentage of voids, result in raw density readings. The pore structure is significant as long as the ultimate strength of lightweight bricks is acceptable. In this study, additives between 3 and 25% by weight were added to the clay mixture. The extrusion of specimens in solid form was carried out using the Laboratory’s vacuum press. Firstly, the extrusion of specimens from the original raw material was implemented. Secondly, it was made on the material mixed with the additives mentioned above. A series of experimental activities were followed to determine the variations of the mechanical and physical properties as well as their production procedures (extrusion, drying, and firing). According to five (5) key properties measured in the current study and compared with the mixture without additives, it was found that the variation in thermal conductivity improvement is between -11% and 19%. The bending strength of the fired products showed a decrease from 16% to 55% except for the addition of bauxite residue, which increased the strength by 8%. Bigot drying sensitivity decreased from 11% to 27%. The density in two cases increased from 2% to 7% while in the majority the mixtures with the additives showed a decrease in density from 1% to 14%. Finally, the addition of the necessary water for shaping during extrusion showed a variation from a 10% decreased to a 14% increased water

Effect of Expanded Perlite in the Brick Mixture on the Physicochemical and Thermal Properties of the Final Products

Thermal insulation is an efficient solution to reduce energy consumption. A great way to reduce the energy consumption of a building is the use of thermal insulation bricks which provide fire resistance and a remarkable thermal capacity, which make them a unique building material for energy efficient buildings. In this study, a fine grain size of expanded perlite was used as additive in a ceramic mass. Brick solid samples were produced from three different mixtures with different ratios of expanded perlite in the mass. From every mixture, three different vacuum values were used. The constructed brick samples were dried and fired in the same conditions and their properties such as bending strength, density and thermal insulation were gathered for six different peak temperatures. The thermal insulation coefficient of every constructed mixture was calculated according to EN1745. It was found that the addition of perlite when keeping the other parameters constant led to decreases in products’ density by 2.9% up to 7.1% and in the thermal conductivity coefficient by 5.4% up to 9.5%, confirming that expanded perlite is a very good porogen material. The bending strength also decreased by 18% up to 28%, but in all cases, it remained well above the minimum accepted value of 100 kp/cm2. The vacuum employed during extrusion proved an important parameter affecting the results; however, its effect proved less significant as the perlite percentage in the mixture increased