Revisión y análisis de los áridos reciclados a partir de la elaboración de una base de datos internacionalpropiedades físico-mecánicas

Abstract

The quality of recycled aggregate concrete depends on the recycled aggregates properties. This study includes a review and an analysis of the physical-mechanical properties that recycled concrete aggregates (that is, recycled aggregates from concrete waste) presents, in order to be used for structural recycled aggregate concrete production. From a practical view point, it would be of a great interest to establish patterns or relationships between the different recycled aggregate physical and mechanical properties. To do that, a database has been developed and, for it, more than 200 international works related with the recycled aggregates field have been analyzed. Regarding the composition, these aggregates show limited impurities, being mainly made up of stone material and adhered mortar. This adhered mortar is the main responsible for the difference between recycled concrete aggregates properties and conventional aggregates. However, an important variability in the quality of this kind of aggregates is found. Firstly, this variability is related with the great difference of original concretes. Secondly, the recycling process is also important, because it influences the quantity of attached mortar. Finally, it should be remembered that there is a significant difference between the recycled coarse aggregate properties and the recycled fine aggregate. Therefore, original concrete, recycling process and size fraction are the three most important issues that should be controlled when recycled concrete aggregates are produced. The database treatment results indicate that density and absorption are the most sensitive properties to the recycled aggregate quality, and a density increase and an absorption decrease with the maximum aggregate size increase have been confirmed. Regarding the “Los Ángeles” coefficient, its value increases with the absorption and it decreases with the density and the maximum aggregate size. Finally, as a conclusion, limiting the recycled coarse aggregate water absorption to 7%, the saturated surface dry density is higher than 2300 kg/m³ and the “Los Ángeles” coefficient is lower than 42%.