masonry course grout max size agg

[boffintech]

Aggregate for grout is required to conform to the grading requirements of ASTM C-404, Table 1. The table shows that for course aggregate, #8 stone and #89 stone, 100% of the material is passing the 1/2" sieve. Therefore one can conclude that the largest size stone allowed in course course aggregate is 3/8".

Today I read over a mix design submittal from LaFarge on an Agilia mix that they refer to as "Block Fill". Interesting phraseology: "Block Fill" not "grout", but I digress.

The mix design is basically blank, but it comes with a letter explaining that the mix is proprietary, that they spent millions of dollars inventing it, and that they aren't going to give up the mix proportions.

OK, whatever, my real beef is with the following...

The letter goes on to state:
1) that the mix "meets ASTM C-476-02 standard specification for course grout masonry"
2) that the "nominal size aggregate 1/2 inch".

Isn't this letter in error? Reason: C 476 section 3.1.3 reads "Aggregates shall conform to Specification C 404." And C 404, Table 1 shows zero material on the 1/2" sieve.

And BTW, the letter is further in error because the name of C 476 is "Standard Specification for Grout for Masonry", not "Standard Specification for Course Grout Masonry."

Who is correct?

 

[apsix]

I would suspect sloppy writing and they meant to say "Standard Specification for Coarse Grout for Masonry"

 

[miecz]

It sounds as though the supplier does not conform to ASTM-C404, and is trying to fog up the issue.

I would reject the submittal. Ask for a statement that the aggregate conforms to ASTM C404, specifically in regards to aggregate size.

 

[MarcbSE]

I typically just specify 3,000 psi concrete for grout, but in your situation I would probably reject the submittal. If they aren't going to provide what is required in the submittal then it gets rejected.

 

[civilperson]

Ask for test results for the thirty samples previously made and tested. Allow material if average strength is two Standard deviations above the requirement of the mix design.

 

[msucog]

i'm using agilia on a job right now. i saw the same scenario but the architect/engineer approved it so i stayed out bringing it up since it wasn't my call. the same scenario happened as far as keeping the mix secret. one thing i would get clarification on up front is the acceptance criteria and testing protocol. get the range of spread that is acceptable. confirm the placement time requirement. make them take full responsibility for the mix as designed and as placed (it is a proprietary mix and they don't want to provide the information you need). if the material is not acceptable, then they should be the ones to reject it...otherwise, they should give letter at the end that they provided a satisfactory product that satisfies all project requirements and that the material was acceptable at the time of placement. the breaks i'm seeing are good. generally, 7 day breaks are 2000-2700 with 28 day breaks 4000-5000 on a 3000psi mix. the only issue i've really seen is that the spread has gotten a little tight (spread of 16") because of the heat and/or longer than desireable placement times. the lafarge guy has been there onsite at each pour and has not rejected the material. the spread requirements on this job is ~20"-30".

i will say this: make any problems with the breaks or placement fully their and the general contractor's problems. have the testing firm check placement times, spread and to note any visual irregularities. oh, and make the supplier provide the testing specifications since astm currently does not have an appropriate test method for SCG (they do for SCC but apparently the SCG method hasn't been approved yet).

http://www.astm.org/cgi-bin/SoftCar.../astm.org/DATABASE.CART/WORKITEMS/WK12135.htm

 

[msucog]

add this to one sentence in my post above:

"if the material is not acceptable, then they should be the ones to reject it...otherwise, they should give letter at the end that they provided a satisfactory product that satisfies all project requirements and that the material was acceptable at the time of placement [to replace normal grout with mechanical consolidation]"--substitutes do no good if it doesn't do as good or better than normal grout after mechanical consolidation.

 

[msucog]

here is a link where i discussed agilia a few months ago. there was some good info posted by others that helped get me up to speed on some of side notes. also shows some of my frustration with contractors in general. isn't the contractor really about 95% of most problems...? (i say yes)

http://www.iccsafe.org/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=10;t=001759#000000

 

[miecz]

This is not only about the strength. It's also about the ability of the grout to get into tight spaces. Half inch aggregate can't do that as well as 3/8.

 

[concretemasonry]

boffintech -

Since there is one minor error in the submittal, there may be others.

a. The descriptive term of the grout used by the supplier seems to be decriptive (coarse grout) of the official specification that includes both fine and coarse categories or types.

b. I think that the term regarding that the "nominal" size of the aggrgate is an inaccurate way of describing am aggregate that has a specified range of gradation.

There are two items to clarify:

First:

I suggest you get a clarification from the submitter to verify compliance regarding the general terminology of the grout regarding the ASTM type of grout.

Also, request support for the claim that the aggregate meets the requirements (C404) for aggregate to be used in the type of grout specified.

Keep in mind that most ASTM aggregate specifications contain some sort of "escape clause" for variations in gradations that are based on some sort of proven equivalency. Since I do not have the ASTM C404 handy, my memory is that out of gradation aggregates are acceptable if they meet the compressive strength and minimum/maximum sizes requirements. - This leads to the second item to clarify, which is what is specified (fine or coarse) and is it correct for the application.

Second:

Check with the specifier to determine whether boilerplate may have slipped through and was used for the ASTM C476 specification or what type of grout (fine or coarse) is really applicable for the specific use - a common problem. Since the problem rotates around aggregate size it would be good to determine if what was specified is correct.

If the coarse grout is acceptable, ask for a detailed gradation of the aggregate used to determine compliance with the ASTM C404 and included provisions for accepting non-complying aggregate gradations. I really doubt if strength is a factor for masonry grout since the biggest problem cam come from too high of strengths. - Grout must be placeable. It is very unfortunate that there is not an adjustment for particle shapes (crushed or natural).

The type of grout used in the project nust be able to fully fill the voids created by the grout cell dimesions and the deductions for horizontal steel reinforcement.

This could be a case of "marketing terms" used in the submittal of a good material, but it is always good to make sure the specifications are also accurate.

Dick