From ordinary rhelogy concrete to self compacting concrete: A transition between frictional and hydrodynamic interactions

This paper focuses on the physical phenomena involved in the transition between ordinary fluidity concrete and high fluidity concrete according to the aggregate content of the mixture. It is shown that there exists a strong transition in the rheological behavior of concrete between a regime dominated by the friction between aggregate particles and a regime dominated by hydrodynamic interactions far less dissipative. It is also demonstrated that it is possible to define a transition criterion between these two regimes. Finally, the consequences of these changes in mix design on the mechanical strengths of the concretes are studied showing that a small decrease in granular skeleton volume fraction, which may generate a decrease in yield stress of almost two orders of magnitude, only reduces the mechanical strength of a few percents.