Pressure grouting

The greatest use of pressure grouting is to improve geomaterials (soil and rock).

The purpose of grouting can be either to strengthen a formation or to reduce water flow through it.

In 1986 a study conducted by the Hazardous Waste Engineering Research Laboratory of the US Environmental Protection Agency tested acrylate, Portland cement and different compositions of silicate material to see if the grouting techniques of direct injection or jet grouting could be used to bottom seal hazardous waste sites with an "inert, impermeable and continuous" horizontal barrier.

When the US government tested the more modern technique of jet grouting for waste control in 1986 they concluded that "the shape and size could not be controlled with sufficient precision in the loess or silt to produce a continuous barrier when the cavities were grouted".

Since first usage in the 19th century, grouting has been performed on the foundation of virtually every one of the world's large dams, in order to reduce the amount of leakage through the rock, and sometimes to strengthen the foundation to support the weight of the overlying structure, be it of concrete, earth, or rock fill.