Effects of rotational shearing on rheological behavior of fresh mortar with short glass fiber.

Highlights • Effects of rotational shearing on rheology of mortars with glass fiber are investigated. • The shear-induced behavior of mortar with glass fiber depends on the matrix composition. • Fresh mortars with glass fibers easily exhibit shear-thickening behavior. Abstract Shear stresses are always applied to fresh concrete during mixing and transporting processes, which have significant influences on the dispersion and agglomeration of cement particles. In this study, the effects of rotational shear mixing on rheological properties of fresh short glass fiber reinforced mortars with different mineral admixtures (containing fly ash and silica fume) were experimentally investigated. The shear rates of 50 s−1, 100 s−1 and 150 s−1 were selected as the rotational shearing rates. The Herschel-Bulkley model was used to characterize the rheological behavior of fresh glass fiber reinforced mortar. Results showed that the shear-thickening intensity increased with the increase of glass fiber volume fraction for the cement-fly ash binary mortar, while the addition of glass fiber resulted in the rheological behavior of cement-silica fume binary mortar changed from shear-thickening to shear-thinning response. After subjecting to rotational shear mixing, the measured shear stress was significantly increased and the fresh mortars with glass fibers easily showed shear-thickening behavior. [ABSTRACT FROM AUTHOR]