Cement bentonite grout mix

[ItsOnlyMud]

Hi,

Does anyone have any guidance on bentonite cement grout mixes. The spec requires 7 to 12MPa 7 day strength.

Any help appreciated.

 

[Ron]

Do a trial batch

 

[BigHarvey]

What is the use of your mix : is it for a cut-off wall or for grouting purposes ?

 

[irawanfirmansyah]

For contiguous bored pile wall, I normally used the following mixture to get compressive strength of > = 150kPa :
73% water, 5 - 6% bentonite, 21 - 22% cement (by weight)

 

[ItsOnlyMud]

Thanks for your replies. It's for an inclinometer. I am asking them why they are specifying such a strong mix. 7Mpa will be impossible to acheive, not to mention pointless for its application! I suspect they have got their numbers mixed up somewhere.

 

[soiledup]

Backfill with a medium grained sand. It's becoming very popular in the UK with many many consultants spec'ing it. Easier to predict how it'll behave and easier to install, more uniform etc etc etc

 

[Stoph]

Here is a link to an excellent paper on this topic. Unfortunately, here in Ohio, we cannot use sand backfill due to groundwater quality policies on sealing a borehole.

http://www.slopeindicator.com/pdf/papers/grout-backfill.pdf