Title: Self-Consolidating Recycled Concrete: Rheological Behavior Over Time
Author(s): I. González-Taboada, B. González-Fonteboa, F. Martínez-Abella, and S. Seara-Paz
Publication: Materials Journal
Appears on pages(s): 3-14
Keywords: recycled coarse aggregate; rheographs; rheology; thixotropy; time-dependent evolution; workability loss
A rheograph is a plastic viscosity-yield stress diagram that systematically reveals the effects of diverse changes on the rheological behavior of the cement-based suspension. In this work, the time-dependent rheological behavior of self-consolidating recycled concrete (SCRC) and conventional self-consolidating concrete (SCC) was compared and the effect of changes in material quantities was assessed using different rheographs. The developed analysis leads to the conclusion that differences obtained depend on the quantity of water compensated in the mixing protocol to take into account the high absorption of recycled aggregates. This fact determines the region of the curves “rheological variations – effective water to cement ratio” where concretes are designed. The high slope region of these curves will be reached when high percentages of recycled aggregate are used, when SCRC is designed with a low water-cement ratio (w/c), and/or when long-term self-consolidating behavior is measured. In these cases, a different time-dependent rheological behavior is expected from an SCRC than from an SCC; otherwise, the rheological behavior over time of an SCRC will be similar to that of an SCC.