Rheological Properties and Thixotropic Behavior of Cementitious Systems Containing Different Fiber Types

Abstract

Fibers which are used to increase the tensile strength of cementitious systems adversely affect the fluidity by making the mixture more cohesive. The effect of fiber type and utilization rate on the rheological and thixotropic characteristics of cementitious systems was a topic covered in the current study. For this, mortar mixtures containing polypropylene, polyamide (PA), and basalt fibers with a 6 mm length were created in three different ratios (0.25%, 0.50%, and 0.75%). According to results, PA- and basalt fiber-containing mixtures showed the best and worst performances, in terms of flowability performance, respectively. In fiber mixes including basalt, the maximum dynamic yield stress (DYS) value was identified. The use of high-range water-reducing admixtures and an increase in the water/cement ratio were shown to result in a drop in the values of DYS, apparent viscosity, the Herschel–Buckley Index, and structural recovery area. It was discovered that fibrous mixtures had a larger structural recovery (anti-thixotropic) area than fiber-free ones.