Effect of Sand Gradation on the Groutability of Cement Suspensions

Abstract

A laboratory investigation was conducted in order to evaluate the effect of sand grain size distribution on the groutability of ordinary and microfine cement suspensions. Four gradations from CEM II/B-M (according to EN 197-1) type of cement were used having nominal maximum grain sizes of 100 μm, 40 μm, 20 μm and 10 μm. Suspensions with water to cement ratios of 1, 2 and 3, by weight, were used. Groutability was evaluated by conducting one-dimensional injections into 45 clean sands with different gradations, using a specially constructed device. Groutability of cement suspensions increases with increasing cement fineness and/or water to cement ratio. Microfine cement suspensions with water to cement ratios of 2 and 3 can penetrate into medium to fine sands. Groutability predictions by groutability ratios are not always confirmed by laboratory injections. Synthesis of the finer portion of the sand gradation (D ≤ D25) affects substantially the result of the injection process and, therefore, is taken into consideration in this investigation by using a "modified uniformity coefficient" and a "modified groutability ratio".