Concrete grout

[JHZR2]

Talking about what is termed “grout” as a building material, not the stuff used in-betwee tiles.

I first read about “grout” when at the 9/11 memorial, where they talked about how they embedded cables in the bedrock for the wtc, and injected “grout”.

Fast forward to today, I have a large workshop building that has a rotten sill plate on one side, and I wish to embed some new L anchors into the CMU foundation (there currently are none, fwiw). Ive been reading about embedment length for anchors, and it talks about grout, not concrete. Ive not seen a good definition of what they’re asking for as grout.

My intention is to fill the CMU with concrete I’ve mixed, and embed the bolts into it. Thus I will cast in place, not have some intermediate material filling an oversized hole. But then I’m using concrete, not grout. And I don’t know what this grout specifically is. I have seen anchoring concrete... and a host of other types...

Anyone able to clarify?

thanks!

 

[tom slick]

grout is basically concrete without aggregate and no lime so it's not mortar either. It's mixed thin so it can pump/flow into the areas it needs to fill. You can buy it in sacks just like concrete.

 

[WyrTwister]

Do not know much about it , but some one makes an epoxy product to use to anchor re-bar into existing concrete . You could also anchor all thread rod .

 

[BlueOvalFitter]

When making supports to hold our carbon steel pipe we would drill for drop in in anchors (3/8" up to 1-1/4") and insert all thread rod with nuts and washers to hold up the steel plate supports. The gap between the bottom of the plate and concrete had to be grouted in. As member tom-slick mentioned in his thread above, that's what we used.

 

[wwillson]

Anyone able to clarify?

I Googled "epoxy grout anchor bolts" and came up with lots of great reading material.

Sakrete is readily available at the chain home improvement stores.

Grout & Anchoring | Sakrete

Non-shrink mixes specifically designed for anchoring.

www.sakrete.com

 

[JHZR2]

I Googled "epoxy grout anchor bolts" and came up with lots of great reading material.

Sakrete is readily available at the chain home improvement stores.

Grout & Anchoring | Sakrete

Non-shrink mixes specifically designed for anchoring.

www.sakrete.com

My application cannot epoxy in. There is no existing structure to drill in to. The cinderblock that is there (hollow) is too brittle to drill and epoxy to.

I intend to mix the right product on site and pack it into the open holes in the existing cinderblock that is there. Once the product is poured, I’ll push the L type anchor bolts into it.

When making supports to hold our carbon steel pipe we would drill for drop in in anchors (3/8" up to 1-1/4") and insert all thread rod with nuts and washers to hold up the steel plate supports. The gap between the bottom of the plate and concrete had to be grouted in. As member tom-slick mentioned in his thread above, that's what we used.

Thanks for sharing. Your application is what I think of when using grout - filling a gap between two items. The difference for me is that I’m filling the entire hole in the block, in full, and embedding the bolts in the material there. The grout isn’t a space filler in that case, it is the structure that holds the bolt. I have seen the epoxy-in anchors in other appplications, and they are strong and permanent. But I’m looking to drop in the anchors because I am dealing with concrete/grout in a wet state.

grout is basically concrete without aggregate and no lime so it's not mortar either. It's mixed thin so it can pump/flow into the areas it needs to fill. You can buy it in sacks just like concrete.

I don’t need to pump it. I have sacks of quickrete 5000 psi high strength concrete. If I don’t add aggregate to it, is this a suitable product to fill the CMU and embed the L anchors in?

 

[RhondaHonda]

Are there rows of blocks staggered or will you just be filling one cavity in the block? I’d be inclined to drill some small rebar into the block if possible to give the grout something to bite if it’s only filling the one cavity.

 

[MNgopher]

The only thing you mix with quickcrete 5000 is water. Everything else (including aggregate) is already in it.

Quickcrete makes several types of grout. Using one of those products will result in a better quality result.

 

[JHZR2]

Are there rows of blocks staggered or will you just be filling one cavity in the block? I’d be inclined to drill some small rebar into the block if possible to give the grout something to bite if it’s only filling the one cavity.

Staggered blocks. Was going to drive a smaller revbar diagonally through the staggered blocks (not drilled, just more or less placed) to add some strength. While I have a hammer drill and can do so, these are old blocks, and if I make them crumble, I could have a worse day...

The only thing you mix with quickcrete 5000 is water. Everything else (including aggregate) is already in it.

Quickcrete makes several types of grout. Using one of those products will result in a better quality result.

OK, I was thinking aggregate was the addition of more, larger, pebbles/rocks. Around here, "exposed aggregate" is common in older concrete work, I think by choice. My experience with the quickrete 5000 is that its pretty smooth without end user addition of more rock/aggregate.

Buying sacks of a "grout" isnt a problem. This isnt big money or a big job. Im happy to go buy sacks of "grout". I just didnt know if there was actually a difference in the product or its characteristics (especially bonding into the CMU openings. If I can use what I have, Im just as happy to do so. Because my take-away is that most folks seem to be thinking about using grout for something like this:

Or going sideways through the CMU...

While Im going vertically through the CMU holes, so the filler needs to "bond" with the CMU, and interlock the levels, with the anchor bolt holding down the sill...

 

[RhondaHonda]

I think wedging some rebar in there should be fine. Just something to give it some bite.

 

[doitmyself]

Please let us know when you find the answer. A Google search is all over the place regarding concrete vs. grout CMU fill. I think there is a problem with semantics. Grout can have less coarse aggregates, which maybe some people confuse it as "concrete". Grout is different than concrete in other ways beyond just aggregates (just my internet reading). Grout is designed to be mixed flowable - mixing concrete "wet" = bad. Grout bonds to CMU better.

A search at the Garage Journal forum "maybe" sways towards using "fill grout" because it has the correct moisture (and other) characteristics to fill and bond with the CMU vs. concrete that is designed to be much drier and poured into non-porous forms. Mortar is used to adhere masonry products.

I would be hesitant to use the 5000 lb. quickrete from my very quick research. This seems to be the more appropriate product: .... https://www.quikrete.com/productlines/corefillmasonrygrout.asp Best would be to visit some local ready mix companies and have an expert advise you.

GJ search: .... "fill concrete block site:www.garagejournal.com" .... help yourself to an hour of reading.
and

https://live-imiweb.pantheonsite.io/wp-content/uploads/2015/10/IMI_TB_MASONRY.GROUT_10.6.09_Page_1.jpg

There's lots of discussion about vertical rebar in the blocks too.

 

[JHZR2]

Please let us know when you find the answer. A Google search is all over the place regarding concrete vs. grout CMU fill. I think there is a problem with semantics. Grout can have less coarse aggregates, which maybe some people confuse it as "concrete". Grout is different than concrete in other ways beyond just aggregates (just my internet reading). Grout is designed to be mixed flowable - mixing concrete "wet" = bad. Grout bonds to CMU better.

Thanks. I agree that its a lot about semantics, and product differentiation.

I think the most telling site Ive found isnt a forum or discussion, but rather here:

Core-Fill Masonry Grout | QUIKRETE: Cement and Concrete Products

The QUIKRETE® Companies are the largest manufacturers of packaged concrete in the United States and an innovative leader in the commercial building and home improvement industries.

www.quikrete.com

Note they differentiate even in the coarseness of their product, relative to the size of the openings in the CMU.

Ill get to the basis of embedment lengths, rebar, etc. after this... I want to understand the fundamental product of interest first...

One thing that is telling however, is the fact that these grouts arent available.

There is specialty grout, at $16/bag (vs $4 or so for concrete)... Example:

Quikrete 50 lb. Non-Shrink Precision Grout 158500 - The Home Depot

Quikrete 50 lb. Non-Shrink Precision Grout is a high strength, non-metallic, non-shrink grout designed for a variety of grouting and anchoring applications. It can be mixed to a plastic, flowable or fluid

www.homedepot.com

But that is not for "core fill". That is for having a non-shrinking product to take up a gap between item a and b. Id hesitate to use it for core fill.

And the core fill stuff is not available at HD or Lowes or such places. So who knows how much Ill need to buy. Which, therein is another problem - I need to do very few of these things relatively. So I dont need to buy 100 bags of grout. And certainly I cant hire a truck when Im doing it DIY, a section at a time, and dont have that many sections to do...

So it still comes back to what is the best product, that I can buy, and use, to do this right...

 

[PimTac]

First of all, I am not totally familiar with this type of construction but I have used hollow blocks to build walls. Tossing this out for thought, will the L bar be set only in the concrete hollow block? To me the hollow block would be a weak link with the concrete fill anchoring the bar. Any side stress or movement could crack the block.

My experience has been to sink the L bar below the block in a concrete footing and it would extend through the hollow of the block. The block would be filled with concrete.

Obviously I am trying to grasp the situation here.

 

[Amkeer]

We would bust out a hole in top and bottom of wall and fill with concrete. You have to continuously tap the wall to make sure it fills properly. Its a pretty tedious task and I would wait until temperatures fall between 60-70 degrees for proper curing. Once cured you can drill hole and use the proper anchor.

 

[JHZR2]

We would bust out a hole in top and bottom of wall and fill with concrete. You have to continuously tap the wall to make sure it fills properly. Its a pretty tedious task and I would wait until temperatures fall between 60-70 degrees for proper curing. Once cured you can drill hole and use the proper anchor.

L anchors are the correct anchor. There’s no way to drill into the bottom and top. This is a three or so high trench footing garage foundation.

 

[JHZR2]

So we started on this project today. What I have is an old (70 year old?) wooden garage building with a cinderblock trench fill foundation. How the building is truly held to the structure now, I don’t know. On one side it’s all block, on the other side (which has a number of garage doors), it is poured, and the sill is bolted down.

On the block side, the sill plate has some termite damage, which is why I’m trying to replace it and bolt it in/down. As noted, I’m not sure if/now it’s held down. As I’ve removed the bad part of the sill, I’ve encountered no bolts, no nails, and none of the cores filled. Just the blocks held together with mortar.

I went to my masonry supply because I couldon’t find the core lock grout anywhere. Even the big supply places catering to masons don’t carry it. Their recommendation was 1 part water, 1 part Portland cement, 2.5-3 parts sand.

I have found that sort of recipe online.

So we jacked up the structure, supported it, removed the sill and cut off the lower ends of studs that looked to have some damage, and then lined up how we were going to do the bolts. We made templates of our 2x6 PT sill to hold the L bolts as the grout cured.

We mixed the grout mixture in small batches.

A lot of the grout would flow into adjacent cells. I guess that means there are gaps in the mortar on lower levels. But we got them full. I used the L bolts to work the grout in, then we filled the holes to the top, and set the final alignment for the bolts.

My wife is a trooper. She helps with everything. She even pours the grout.

Partial fill, working it around with the long L bolts.

Final location, aligned via the template.

Onced suitably cured, the new PT sill will go on, with a strip of 6 mil plastic underneath as a moisture barrier. This is an old garage, it’s rea goal is to keep rain and sun off of stuff, not much else. It’s not air right by any stretch.

Then I’ll Lift back up a tiny bit, sister the cut studs, add others, and drop the section back down.

I have over 200 linear feet of sill, not including the openings where the bay doors are. I have three sections that need replacement, but I might do the entire thing since I can’t tell that it’s held down anyplace on the one side.

For those unfamiliar, this approach is not uncommon. One of my favorite YouTube personalities has a good video on doing just this.

 

[doitmyself]

Nice solution on the fill grout. Are you going to use treated lumber for the sill plate?

 

[JHZR2]

Nice solution on the fill grout. Are you going to use treated lumber for the sill plate?

Absolutely will use PT over 6 mil plastic. Will also look into how to flash it under/past the clapboard sheathing/siding.

 

[ABN_CBT_ENGR]

Looks like an excellent job- appears done perfectly to standard

On your earlier comments (in case there is any question) and I have to live by and certify things to API 686 all the time for loads far exceeding this...

In simple terms ( many here have posted all the major points- I'll just put them in context with a foundation)

Grout is cement just without aggregate and some strength. Given its thinness it pours easier and "grabs" things like anchors better so its preferred as a base material. This works for most static loads. ( such as this)

On really big machines, heavy vibrations or pulling loads, the anchors would beed to be in the concrete for strength then the grout for mass.

The more grout you worked into the voids- the stronger it will be

 

[Amkeer]

J-bolt. I was thinking vertical application? As far as the flashing you may be able to pickup material they use for roofing flashing on block walls or you can have a sheet metal fabricator make some galvanized flashing width of block with a bend on the outside and another 22 degree bend. 8x2. The outside 2 inch bend will have a 1/4 inch bend at 22 degrees similar to drip edge.

I would forget the visqueen as it will hold moisture and cause problems over time. They make a material for sill plates that will breathe its probably not needed.

The only thing I would have done different is a number 5 bar but with that vintage block it would have probably caused more problems.

Have termite company trench and treat after you are 80% complete.