In situ materials characterization of full-scale recycled aggregates concrete structures

• Full-scale structures made with coarse recycled aggregates from crushed precast concrete elements.
• Unprecedented study on the in situ performance of real structures in concrete with recycled aggregates.
• In situ results and equivalent laboratory results agree to a great extent.

Aiming at characterizing the behaviour of concrete structures made with coarse aggregates recycled from crushing concrete elements from the precast industry, extensive testing was performed in four full-scale recycled concrete structures, made with various recycled aggregate ratios. This paper concerns the in situ concrete characterization tests carried out. The purpose was to study the use of the coarse fraction of the recycled aggregates (RCA) at different replacement ratios and the possibility of including a superplastizer (SP) in concrete mixes, as a means of replicating the properties of a conventional concrete (RC) mix. The results showed that the behaviour of the concrete mixes produced with these aggregates, originated from the precasting industry, i.e. with high quality, is almost unaffected by their incorporation. Only the results of the ultrasonic pulse velocity (UPV) tests were affected by RCA incorporation, but the loss was lower than the one reported in the literature. This study concluded that these RCA have, in fact, high quality and are suitable for the production of recycled aggregate concrete to be used in structural elements. The SP more than offset the effects of RCA incorporation on the concrete mixes. To the authors’ best knowledge this is the first investigation concerning the in situ concrete properties of full-scale recycled aggregate concrete structures.