COMPACTED UNCALCINED WASTE FROM GRAVEL AND SAND WASH MUDS OF AN AGGREGATES PLANT AS WASTES VALORIZATION STRATEGY

Fine waste management from quarry has been commonly the final disposal in mining tailings and as refilling material for landscape recovery in areas already exploited. However, different uses of these wastes have been studied, highlighting earth constructions because a new economic benefit is generated and the environmental impact is reduced. Moreover, compared to cement constructions, earth constructions are environmentally friendly and represent energy saving due to their low emission of CO2 by low or no-cement content in their manufacture, in contrast to good physical and mechanical properties obtained. So, in this work, the use of waste muds from an aggregates plant (as a result of crushing and washing process) was evaluated as a circular economy strategy. Raw materials were chemically, mineralogically, and physically characterized and were employed in the elaboration of cubic specimens of uncalcined material, which were hydraulically compacted in metal molds at mixtures of waste muds, commercial gray cement, and washed fine sand. The cubic specimen’s performance was evaluated by Simple Compressive Strength (SCS) and water absorption tests. In the best configurations, an increase in SCS of 221.3% (8 MPa) on samples with 20% cement with respect to samples of only waste was found and, in turn, an increase of 517.3% (15 MPa) when these were cured in water was also found. Thus, wastes mixed with small amounts of cement are promising in the manufacture of Compacted Earth Specimens (MCES), particularly as masonry or structural elements made of uncalcined wastes.