Abstract

The use of very fine cement grouts for injection into fine-to-medium sands has been proposed to circumvent problems associated with the permanence and toxicity of chemical grouts and the inability of ordinary cement grouts to permeate soil formations finer than coarse sand. A laboratory investigation was conducted in order to evaluate the penetrability of cement suspensions. Four gradations from CEM I (according to EN 197-1) type of cement were used having nominal maximum grain sizes of 100μm, 40μm, 20μm and 10μm. The properties of suspensions, with water-to-cement (W/C) ratios of 1:1, 2:1 and 3:1 by weight, were determined in terms of apparent viscosity. Penetrability was evaluated by conducting one-dimensional injections into five different, clean sands using a specially constructed device. Penetrability of cement suspensions increases with increasing water-to-cement (W/C) ratio and cement fineness. Microfine cement suspensions with water-to-cement (W/C) ratios of 2:1 and 3:1 can penetrate into medium-to-fine sands.

Keywords: Permeation grouting; Suspensions; Water-to-cement ratio; Microfine cements; Grouted sand