The aim of this paper is to characterize the effect of the dosages of diutan gum and limestone powder (LSP) on the workability and the rheological behaviour of grouts and compare the results to similar grouts made with ordinary Portland cement and welan gum with 0.40 water-to-cementitious materials ratio (W/CM). The fresh properties of reference grouts made without any viscosity modifying agent (VMA) and with superplasticizer (SP) were compared to those of grouts made with 0.04, 0.06, and 0.08% diutan gum by mass of CM. The effect of replacement of cement by limestone powder at 12%, 29% and 45% (by mass) was also investigated. The results showed that for any given dosage of SP, the increase in the dosages of diutan and welan gum led to an increase in yield stress, apparent and plastic viscosities, and to a reduction of fluidity. For both reference and LSP mixes, diutan gum grouts exhibited a greater yield stress, apparent viscosity and plastic viscosity than welan gum grouts. The apparent viscosity at low shear rate decreases dramatically than that at high shear rate when the dosage of SP increases which attributed to the pseudoplastic characteristics of these mixes containing VMA. The incorporation of LSP resulted in a significant decrease of yield stress and a slight reduction of plastic viscosity.
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