Influence of measuring system on rheological behavior of PVA-fiber reinforced mortars

Rheological analysis of fiber reinforced mortar is a complex subject since fibers induce significant flow disturbances in the paste-fiber system. The aim of this study is to compare the rheological properties of PVA-fiber reinforced mortars determined by two different rheometer probes: vane system and a sphere that is dragged across a fluid (ball measuring system, BMS). The yield stress of the mortar with and without fibers changed significantly by varying the superplasticizer content. Mixing time also varied from 1 to 3 min. BMS seems to better discriminate and quantify the fiber reinforced mortar rheology. For this system, some minor measurement artifacts introduced measurement variability between the first and second stage of measurement. The Vane system gave less consistent results. Significant strain localization and fiber network evolution in the sheared zone were observed, strongly affecting the measurements. It should be noted that in both systems, the mixing time did not change significantly the composite behavior. .