Effectiveness of Microfine Portland Cement Grouting on the Strength and Permeability of Medium to Fine Sands

Abstract

The purpose of this research was to investigate the grout properties of microfine Portland cement whose specific surface area was greater than those of the same kind products frequently cited in the relevant literature. In this regard, viscosity,  setting time and stability of microfine cement suspensions were initially studied. It was seen that the sedimentation and the setting time increased but the viscosity decreased as the water/cement (W=C) ratio of microfine Portland cement suspensions increased. In addition, the penetrability of microfine Portland cement suspensions with different W=C ratios into various graded medium-to-fine sand specimens prepared at a relative density of 30% was tested under grouting pressures ranging from 0.25 to 0.5MPa. It was observed that the penetrability of cement suspensions into the specimens was successful and increased as the W=C ratio increased. All grouted samples were kept in humidity room at a temperature of 20°C until testing time and subjected to permeability and unconfined compressive strength tests at different time intervals. The unconfined compressive strength decreased as the W=C ratio as well as the fine content of sand increased. Permeability tests conducted on grouted specimens with a period of two months revealed that they were impermeable.