Correlation between L-box test and rheological parameters of a homogeneous yield stress fluid

In this paper, a theoretical analysis of the L-box test is proposed in the case where no heterogeneity is induced by the flow. It is first demonstrated that if the standard procedure is followed and the L-box gate promptly lifted, the flow is dominated by inertia effects, depending on the lifting speed of the gate and thus on the operator. When the gate is slowly lifted, the flow and flow stoppage of a homogeneous yield stress fluid in a bounded channel are first studied. The obtained theoretical shape of the sample at stoppage is successfully correlated to the experimental results in the case of limestone powder suspensions. Then, the influence of steel bars was included in both the theoretical and the experimental study. Finally, practical applications of the present work to the case of real self-compacting concrete are suggested.