Model fluids substituting fresh UHPC mixtures flow behaviour

Carboxymethylcellulose (CMC) and ultrasound gel (USG) seem to be suitable clear model fluids to substitute real ultra-high-performance concretes (UHPCs), enabling experimental monitoring of events occurring within these mixtures at similar flow behaviour. USG is eligible for UHPC mixtures with significant yield stress. CMC having a suitable concentration is better for UHPCs exhibiting indistinct yield stress. The rheological behaviour of real UHPC mixtures as well as substituting model fluids was measured using a non-standard system consisting of a vessel stirred by an anchor or a screw agitator. In addition, a standard rotational rheometer system with concentric cylinder geometry was used for optimization of the above-mentioned method of measurement and also for measuring the rheological parameters of the substituting model fluids. This article deals with the methodology for measuring the rheological properties of these substances and presents the results of the measurements using flow curves and rheological models.