Magnesium oxide as alternative binder for unfired clay bricks manufacturing

Replacement of fired bricks by unfired ones could be an effective way to reduce the building industry environmental footprint: Their manufacture not only requires less energy and natural resources but also generates less waste. Bricks are based on the use of an additive cementitious material in the form of a binder, usually lime or cement. Such additives have a great environmental impact owing to the high energy consumption and CO2 during in their manufacturing process. In this article experiments are carried out in order to investigate the applicability of a MgO rich industry by-product as a binder for the production of unfired clay bricks. From the experiments, the MgO was observed to show ability to enhance the mechanical properties of a clay brick in much the same way as lime does. Water absorption tests on bricks revealed the superiority of MgO over lime in enhancing the durability properties of unfired bricks. The laboratory results demonstrate the high potential of MgO based additives as alternative binders to the calcium based ones. Consequently, this offers opportunity for reducing the environmental impact associated with the use of fired clay bricks. In addition, it could allow an effective way for the valorization of MgO containing industry by-products that currently discarded to landfills.