Additives for grout
Posted by D from London, OT, GB on March 10, 2007
Hi Bruce
I have a question about the use of additives with grouts designed for deep grout curtains or consolidation grouting in dam foundations. The grout curtains are to reduce permeability under a dam and reduce water losses. Often at site the contractor orders significant quantities of additives for concrete and is therefore reluctant to order special addtives for grouts, claiming that they are anyway suitable. Which classes of additives are suitable for grouts? Typically a grout mix would be w/c 0.5 up to 1, with or without bentonite, occasionally with sand where high takes need to be stopped.
I have another question about the use of additives with bentonite slurry (typically 1-2% of cement). Are there any additives that are designed to work with bentonite?
Many thanks
To reduce permeability in concrete and grout mixes, addition of supplementary cementitious materials like Silica Fume and Fly ash should help. I would also recommend the use of a water reducer or a high range water reducer to reduce the amount of mix water and make the mixture more impermeable.
I don’t have much information on additives for bentonite. Try to do a search for that in “Google”.
