ABSTRACT
This section presents one of the first experimental construction trial site that was carried out in 2014/2015 within the RECYBÉTON National Project/PN RECYBÉTON.
The objectives were as follows:
To produce recycled aggregates (RA) having sufficient characteristics to be used in structural concrete, such as recycled gravels (RG) and recycled sands (RS).
To study various concrete mix designs with a replacement ratio of 0% up to 100% of the “traditional” aggregates, or natural aggregates (NA), by recycled aggregate (RAs).
To select a mix design, enabling to produce a C25/30 concrete for structural use.
To produce the concrete in a ready mix plant, using only the existing equipment.
To place the concrete on a construction site in reinforced concrete elements, such as walls, and architectonic sidewalks.
The relevant conclusions are that if it can be recommended to use recycled concrete coarse aggregates with quite a high replacement ratio, the use of recycled concrete fine aggregates/sands is more delicate.
The use of superplasticizer allows to adjust the workability and the rheology of the recycled aggregate concrete (RAC).
In our study, the RAs are high-quality ones, but a larger use of recycled sand would lead to poor durability characteristics: shrinkage, water porosity, and gas permeability, increase quickly with the percentage of sand substitution.
422However, these results have to be considered with care because we were aiming aimed to produce C25/30 concrete for rather small constructions. High-durability objectives do not concern our study and mean values for potential durability evaluation are promising.We draw the attention of future users of RAC to anticipate on the number of storage silos that the RMX (ready-mix) plant can handle, in order to use 4 to 6 different sizes of aggregates.
