Strength and permeability properties of sodium silicate-glyoxal-stabilized silt and fine sand

Abstract

In this research, the suitability of sodium silicate-glyoxal (SG) grout to stabilize silt and fine sand was investigated. In addition, the permeability and strength properties of grouted silt-fine sand samples were determined under two particular curing circumstances and at different time intervals. Initially, the gelation time, viscosity and syneresis of SG solutions prepared at different contents were investigated to determine the suitable mixtures. In this regard, the solutions of SG2 and SG6 were determined to be the most suitable for the grouting purpose of silt and fine sand samples. Thereafter, silt and fine sand, as well as silty fine sand samples, were successfully grouted with the selected solutions of SG2 (glyoxal/sodium silicate ratio 0.23) and SG6 (glyoxal/sodium silicate ratio 0.25). Unconfined compressive strength (UCS) tests were conducted on the successfully grouted air-dried and wet-cured samples on days 7, 14, 28, 56 and 90 of curing. While the UCS values of air-dried samples ranged from 1.36 to 2.17 MPa, the UCS values of wet-cured samples varied from 0.43 to 1.01 MPa. Whilst the lowest UCS of grouted samples was obtained under wet-cured conditions, the highest UCS of grouted samples was recorded under air-dried conditions. Moreover, the permeabilities of injected silt and fine sand samples ranged from 1.02 x 10(-5) to 3.77 x 10(-6) cm s(-1). The permeabilities of silt and fine sand samples were decreased through SG grouting by two-four orders of magnitude. In general, SG grouting, organic in nature and environment friendly, was successful in stabilizing the silt and fine sand where the cementitious grouting failed to penetrate.