TERRA COTTA BRICKS IN MATTER INSULATING AND LIGHT BY COAL ADDITION IN AN ARGILLACEOUS MASS

The idea of the passage of a light concrete product to that of a terra cotta product is fixed on the launching of a manufacturing range of brick products satisfying some properties which will be adapted to contemporary construction and the modern architectural tendencies. This is carried out by using a mixture of two types of clays, grey clay and yellow, plus an additing of porogene agent coal which, under the effect of the heat of the furnaces of cooking, sublimates, thus creating pores. This adaptation enabled us to develop a recipe of manufacture and a judicious design, by considering a method of production more economic and obtaining a material of better quality. The nature of coal depends on its characteristics in volatile matters, calorific value, density etc. The use of coal in the field of ceramics is to be explored. The work concerns four mixtures (M1; M2; M3; M4) corresponding to the proportions: (50 - 55 - 60 % and 65 %) for the first type of clay. As for the second the values are 30 % and remain constant. The contents of coal corresponding to each mixture are respectively: (20 - 15 - 10 % and 5 %) with granulometry of (0,25 - 0,50 - 1,00 and 1,60 mm). The technical values of the variant M2, with, a granulometry of 1,60 mm confers mechanical qualities more or less interesting, for example, a mechanical resistance (compression) of the order of 361.6 kgf/cm2 corresponding to a bulk density of 1.88 g/cm3. These structural components out of terra cotta light cumulate structural properties and insulating qualities. In addition, this type of materials, by their porosity, contributes to a good quality of the interior air, in particular by an effective hygrometrical regulation. Thus according to a study of the CSTB, a mono alveolar terra cotta wall absorbs a volume of steam 5 times more important than a wall in concrete blocks, without its initial qualities.