Injectability of fine sand with cement-based grout

The objective of this paper is to propose a methodology that can be used to characterize the injectability of cement grout in fine sand deposits. Grout mixtures made with a conventional portland cement and a microfine cement were tested. The grouts were prepared with water-to-cement ratios varying between 0.5 and 2.0 and contained different concentrations of silica fume, superplasticizer, and colloidal agent. The grout mixtures were tested for rheological properties as well as for stability. The stability was evaluated using the forced and static bleeding tests which are necessary to evaluate the behavior of the cement suspension during grouting. The injectability of the grout was evaluated using a sand column test adopted from the European standard NF P18-891. Various sand gradations and moisture conditions (saturated vs. wet sand) were investigated. The results of this investigation are reported in this paper and show that it is possible to inject cement-based grouts in fine to medium sands using highly flowable, yet cohesive cement grouts.