Physical, chemical and mineralogical properties of fine recycled aggregates made from concrete waste

• Physical, chemical and mineralogical characteristics of fine aggregates from crushed concrete.
• The amount of fines produced during crushing depends on the jaw’s aperture.
• The smaller size fractions present high mortar contents and few natural aggregates.
• The mineralogical composition of recycled aggregates is not greatly affected by particle size.
• The particular features of fine recycled aggregates do not justify restraining their use.

This paper assesses the physical, chemical and mineralogical characteristics of fine recycled aggregates obtained from crushed concrete waste, comparing them with two types of natural fine aggregates from different origins.A commercial concrete was jaw crushed, and the effect of different aperture sizes on the particle size distribution of the resulting aggregates was evaluated. The density and water absorption of the recycled aggregates was determined and a model for predicting water absorption over time is proposed. Both natural and recycled aggregates were characterized regarding bulk density and fines content. Recycled aggregates were additionally characterized by XRD, SEM/EDS and DTA/TG of individual size fractions.The results show that natural and recycled fine aggregates have very different characteristics. This should be considered in potential applications, both in terms of the limits for replacing amounts and of the rules and design criteria of the manufactured products.