Rendering Mortars with Low Sand and Cement Content. Incorporation of Sanitary Ware Waste and Forest Biomass Ashes

Abstract

The incorporation of wastes in new materials and products is an emerging trend, reducing virgin materials’ consumption and landfill deposition and the associated environmental impacts. Cement-based mortars can encapsulate some wastes, with the benefits stated above. In three previous researches, it was found that forest biomass bottom ashes (up to 15% by volume of cement), powder of sanitary ware (up to 20% by volume of sand) and sanitary ware particles above 2 mm (100% by volume of sand) can be incorporated in rendering mortars, replacing cement or sand. Several tests were performed, and it was found that each waste’s incorporation presents advantages and limitations, when compared with a reference mortar. In this research, the aim was to take advantage of the best features of each waste, combining them in order to optimize the new mortars’ characteristics. Therefore, mortars with one, two and three wastes were analysed in this research. The ternary mix mortar had a volume of wastes equal to 83%, resulting in a mortar with 15% less cement (by volume) and without any natural aggregate (all replaced with the sanitary ware wastes). The fresh, water and mechanical behaviour of the mortars with and without wastes are presented in this research. It was concluded that it is possible to take advantage of the best features of each waste and achieve mortars simultaneously with high volume of wastes and a better performance than the reference mortar (without wastes).