A hand excavatable permeation grout is important when working in environments where mechanical excavation isn’t possible. In most permeation grouting applications, the stronger the treated soils, the better. This includes chemical underpinning applications, and improvement of unstable soils.
However, when excavatability is important, cementitious and polyurethane resin permeation grouts can be very problematic. CJGeo specializes in permeation grouting using acrylic and colloidal silica grouts to stabilize soil, eliminate permeability, and still ensure hand excavatability.
Acrylic Grouting
Acrylic grouts are polymers that are highly elastic and will typically have high elongation before failure. Acrylic resins are generally diluted with water and then pumped 1:1 with a salt solution of variable concentration to control set time.
Set time is adjustable on site by varying dilution ratios, and catalyst concentration. Acrylic grouts are typically around 10 centipoise, which means they pump and flow like water. In general this is advantageous in permeation grouting because it maximizes the likelihood that the grout uniformly permeates the soil treatment zone.
When cured, acrylic grout is the consistency of a cooked egg white or silicone caulk. Cured acrylic grout is quite stretchy. It is also easy to cut. This makes hand excavating through treated soils relatively easy.
Colloidal Silica Grouting
Colloidal silica grouts are a colloidal suspension of silica nanoparticles in water. Typical concentrations are either 15% by mass or 30% by mass. The viscosity of colloidal silica grouts is very close to water; usually below 10 centipoise. Colloidal silica is unique in that it is pumped with a salt solution that’s typically between 2 and 10 percent by mass of sodium chloride in water.
Soils treated with colloidal silica tend are generally impermeable and friable. This makes colloidal silica grouting particularly well suited for grouting shaft breakins and breakouts in saturated non-cohesive soils, in that there is rather minimal strength increase, but very uniform impermeability.
Speak With An Expert
Facing a challenge trying to identify the best grout for hand excavatable permeation grout? Give us a shout or shoot us a text. Click the state marker for the location of the project for contact info for the appropriate rep.
