Silica sol as grouting material: a physio-chemical analysis

Silica sols have increasingly been used in diverse applications in several different areas, one of which is the field of grouting. Grouting of strata can have different purposes such as stabilization of loose sands, preventing leakages etc. One area that has been explored for some years is the permeation grouting (or grouting of rock) using silica sol [1]. In Scandinavia the permeation-grouting is a primary method used to prevent the leakage of water into tunnels and hard rocks. It requires a grout to be applied into the leaking cracks in order to physically block the water from entering the tunnel. For the grout to be effective it must thus enter cracks of varying size, which puts demands on the rheological properties of the grout. The grout must also once applied, last for a considerable time and thus be stable in the conditions experienced in the rock, primarily against water of different compositions containing various types of ions and pH levels