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Re: Epoxy Grout for Rock Anchors

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My vote would also be with Mark (for a high strength shrinkage compensated
cementitious grout).  As Nels pointed out, it's probably too much volume for
epoxy.  The EPCON acrylic he suggested might do the job, but would be more
expensive and less compatible with the surrounding rock in terms of thermal
and chemical characteristics.  Some other things to think about:  centering
devices to assure the rods stay in the middle of the holes and drilling
techniques.  If this is hard rock the holes may have very smooth sides
(potentially glass smooth due to drilling heat) and bond between the grout
and the hole is likely to be the weak link in your anchorage system (it's
almost certainly not the filler itself, which is loaded primarily in shear,
or the bond to the anchor rod, which is presumably deformed and almost
certainly has a development length a lot less than the fifteen feet of
embedment).  Out here in California we don't have much hard rock, by I'll
bet you do in Nova Scotia and if that's what you're dealing with (e.g., if
your rock stresses are high) you may want to try to find a way to create
some roughness.

Drew Norman, S.E.

----- Original Message -----
From: "Mark Gilligan" <MarkKGilligan(--nospam--at)>
To: <seaint(--nospam--at)>
Sent: Thursday, November 09, 2000 6:57 AM
Subject: Epoxy Grout for Rock Anchors

> Steven
> You might want to consider other types of grout than epoxy grout given the
> relatively large space between the reinforcing bar and the 3 inch diameter
> hole.  If the space is too large the epoxy will generate too much heat and
> as a result it will not be as strong as it was likely assumed.  Check with
> manufacturers of grout products such as Master Builders.
> Mark Gilligan
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>>I have a project in which I am utilizing grouted rock anchors to resist
> uplift
> forces. Depth of vertical anchors is 15 feet. Anchors will be epoxy
> coated rebar. The three inch drilled holes will likely have up to 10 feet
> of
> groundwater in them.
> I am searching for an epoxy grout product that is insensitive to the
> presence of water and will cure in 5 degrees Celsius (40 degrees F)
> conditions. I have talked to a couple of suppliers, but they are wary
> about the wet conditions. Any recommendations?<<<