5000psi grout as a structural footing?

• Feb 26, 2003

• #2

jheidt2543

Civil/Environmental

Sep 23, 2001

1,469

US

Why use the grout? Concrete is about $65-$75/CY and non-shrink grout is about $34-$50/CF (yes, CF which equals $918-$1,350/CY) So, why use grout?

 

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• Feb 27, 2003

• Thread starter
• #3

paullaup

Structural

Feb 26, 2003

29

US

The issue of cost is irrelevant in this case. The contractors want to uise it. Maybe they have an abundant supply of it. The question was asked to find out about the technical implecations, not the economic implications.
Anyone with answers??

 

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• Feb 27, 2003

• Thread starter
• #4

paullaup

Structural

Feb 26, 2003

29

US

The issue of cost is irrelevant in this case. The contractors want to use it. Maybe they have an abundant supply of it. The question was asked to find out about the technical implecations, not the economic implications.
Anyone with answers??

 

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• Feb 27, 2003

• #5

smaug6

Structural

Apr 10, 2001

10

US

Maybe water permeability reduction is the issue the contractor wants to address.

 

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• Feb 27, 2003

• #6

jheidt2543

Civil/Environmental

Sep 23, 2001

1,469

US

Ok, so here are some thoughts if you use the grout (I'm assuming a premixed grout product, not a sand cement grout):

1. It should not be a metalic grout.

2. I would think you could design it the same as a reinforce concrete footing. I do seem to remember that the set time for grout is much faster and they tend to generate more heat in large sections. So, I would find out what grout is being used, get a product data sheet and contact the manufacturer's techical staff to verify what I just said.

3. To get a better yeild, some couse aggregate should be used. So, I would request a mix design and test cylinders.

4. I've never seen grout used as a footing this way because of COST.

 

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• Feb 27, 2003

• #7

Ingenuity

Structural

May 17, 2001

2,374

US

paullaup,

When you say "grout" it may take on several meanings. Clarify with the contractor on exactly what he/she defines as grout.

Water and cement is also a grout - but I would not use it for a footing application, even though at w/c=0.40 I will probably get 6,000 + psi at 28 days on 2" cubes!

Does it have course aggregate of max size of 3/8", or only fine (sand) aggregates?

A sanded grout will potentially suffer from excessive shrinkage for a strip footing element which I imagine is 12" wide min and a depth of 8+ inches, and somewhat lengthy.

Get a copy of the contractor's proposed grout mix design before you comment/commit.

Since you state that this wall is non-structural you are probably not that concerned with with bond related issue anyway, and I am not sure if it will be a factor anyway as reinforced CMU walls and bond beams/lintels are grouted and bond is not specifically addressed in these situations.

Ask if it going to be site mixed or ready mized, to ensure some quality - If you accept the alternative make it a "performance" criteria where the emphasis is on the contractor to achieve the same/equal to a concrete footing.


HTH

 

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• Feb 28, 2003

• #8

dicksewerrat

Civil/Environmental

May 16, 2002

1,946

US

Require third party testing of this"grout". Cylinders and beams.

 

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• Mar 1, 2003

• #9

jheidt2543

Civil/Environmental

Sep 23, 2001

1,469

US

Contact L&M Construction Chemicals, Inc. at

http://www.lmcc.com.

They manufacture a variety of grout materials and their techical services department may well be able to answer your questions in more detail.

 

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