Recycling mining and construction wastes as temper in clay bricks

Abstract In the last years, the ceramic sector started to focus on the exploitation of local georesources with circular economy solutions based on waste recycling. The present work aims to assess both the technological feasibly of waste recycling in the clay bricks manufacturing and the effect of different degreasers on the same clay body in order to disclose which factors control technological behavior. Non-plastic waste materials (e.i. mining and construction wastes) were added to a plastic clay and the brickmaking process was performed at the laboratory scale. The main technological properties of the semi-finished and finished products does not suffer any significant variations, indeed with the addition of mining and construction wastes were improved the plasticity reaching optimal values for the clay bricks extrusion. A clear disadvantage is found related to the decrease of mechanical strength, both in dry and fired products, ascribable to the convergence of microstructural factors. In conclusion, the different effects on the technological properties of clay bricks are correlated to the type of waste added as degreaser and the complex interplay of particle size distribution and mineralogical composition in ceramic matrix.