Grout slump 2

[WARose]

I was looking at a old drawing earlier today, and the grout slump is called out as: "Slump shall be 9” + 1"."

Does anyone know what that +1" is? Is it giving them some wiggle room with site conditions?

 

[BridgeSmith]

I would think it would mean the range is from 9" up to 10", which is still a fairly tight tolerance for slump, but it seems an odd way to state it.

 

[Ron]

The draftsman couldn't find the "-" on his Leroy template!

 

[12345abc6ttyui67]

Draughie didn't copy the engineer's comments correctly?

9" +/- 1"?

Or of course the engineer didn't write what he wanted correctly

 

[CANPRO]

Is a slump test even valid for slumps that high? I thought it maxed out around the 6"-8" range.

 

[jgailla]

You're right. Should be a cone test.

 

[WARose]

Never seen a slump test without a cone.

I think the +/- theory is valid.

 

[CANPRO]

It was my understanding that when the slump exceeded the limits of the slump test, it was more of a "spread measurement". I'm no expert on this though.

 

[WARose]

Wonder if there is (somehow) a equivalence. I.e. a spread out equals [x] amount of slump.

 

[WARose]

Found this from NCMA:

Both the Specification for Masonry Structures (ref. 7) and ASTM C 476 require grout to have a slump between 8 and 11 in. (203 – 279 mm).

[later]

Because of the fluid nature of the material, traditional measures of consistency and flow such as the slump cone test (ASTM C 143) are not applicable to SCG [SELF-CONSOLIDATING GROUT]. A slump flow test is used instead, which is an adaptation of the conventional slump cone test. In the slump flow test, SCG is loaded into an inverted slump cone. The cone is removed and the flow of the material is observed and measured. Typical slump flow spreads for SCG range from 20 to 30 in. (508-762 mm).

http://ncma-br.org/pdfs/52/TEK 09-04A.pdf

So on the one hand they call for slump test results in excess of 8".....but for SCG, they say it is too fluid for anything but a spread test.

 

[BridgeSmith]

"Wonder if there is (somehow) a equivalence."

I'd bet there's at least an approximate empirical one out there somewhere. If not, a few experiments could produce one rather quickly.

 

[dik]

The high slump of the grout is not representative of the actual grout placed... the moisture was removed by soaking into the CMU wall. I've often seen grout placed and the was was visibly 'wetted' as the grout filled the voids.

Dik

 

[jgailla]

Sorry, I meant a funnel test.

 

[dik]

Funnel tests may not have been common at the time of construction.

Dik

 

[Ron]

A slump test is, in theory, valid to 12 inches minus the diameter of the largest coarse aggregate. In practicality about 10 to 11 inches is maximum and very fluid.

Using a flow cone is limited to grouts with very small or no coarse aggregate.

 

[masonrygeek]

As for the original question, they probably wanted a slump test to be 9" and to provide some leeway they only went one way to +1". They didn't want it to have a lesser slump of 8" so a +/- may not have been appropriate as Hotrod10 mentioned. There needs to be some tolerance.

As for grout, remember we are not talking about concrete. As dik noted, masonry grout has a very high slump since the masonry units will absorb moisture from the grout as it is placed. So you need those high slumps, i.e. 8" to 11".

As for the "spread measurement" (actually called slump flow test), it is only applicable to self-consolidating grout (SCG). Regular masonry grout uses a slump test (

https://www.youtube.com/watch?v=ubUtI4eBHeA)

and SCG uses a slump flow test (

https://www.youtube.com/watch?v=NTBmcPNdrnA,

go to 2:25 for test). There is no equivalency between the two since they are different tests and there is no need to make one. Grout slump for regular masonry grout follows ASTM C143. Slump flow test for SCG uses ASTM C1611.