Prevention of bleeding of particulate grouts using biopolymers

The potential applicability of several biopolymers, including xanthan gum, diutan gum, acacia gum, modified starch, guar gum and a cellulosic polymer, for maintaining the solid particles of a particulate grout in suspension has been evaluated through static bleeding tests. The grout material investigated was ground granulated blast-furnace slag (GGBS) cement prepared at different water to binder ratio values ranging from 2:1 to 5:1. Among the biopolymers studied, diutan gum and xanthan gum were found to have the highest performance in bleeding prevention at very low concentrations in ranging 0.25-1.0%. A synergy was observed for xanthan gum and guar gum and for xanthan gum and cellulosic polymer combinations. This helps reduce the overall amount of biopolymer required for suspension stabilization. By measuring the zeta potential and viscosity values of the biopolymer-added grouts, the mechanisms underlying the sedimentation inhibitory action of the biopolymers are discussed. (C) 2018 Elsevier Ltd. All rights reserved.