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Mortar Cement - ASTM C 1329

6587 Views 28 Replies 7 Participants Last post by  Fouthgeneration
This is a new one to me. The specification dictates minimum bond and tensile strength, along with a few other parameters. Anyone ever used this type of mix?
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Sounds like a restoration mix, does it mention compressive strength at all?
Not in the spec, it is bagged in Types S N M or O.
After reading on it a bit, my concern is that it is a physical property relying upon lab testing of a proprietary mix. If an issue comes up in the field, the only method to resolve the issue is with field tested samples. No provision is made for field testing or sampling in the standard, nor in any other the previous standards referenced.

It is win-win for the manufacturer, lose-lose for the sub and general contractor. I can see why it is such an unknown and little used standard in spite of being around since 1995.
Tscar, "Mortar Cements" as Spec'ed by ASTM C 1329 if mixed with ASTM graded sand will meet certain test minimuns.... Note creation of "mortar cements " as subset of existing 'masonry cements'.

Standard takes legacy commodity types of premixed masonry cements dividing them by their weight/Cubic foot bag, and declaring 28 liters ~ equal to 1 cubic foot. M,S,N mortar cements divided by their weights/cubic foot... that matches current products offered by lafarge, hoclim, etc......

Some preblended mixes made with more limestone dust then hydrated/hydralic lime won't meet the tensile/flexure hoops of ASTM C1329. This is where C 1329 separates the sheep from the goats.

Use of mortars that will yield higher tensile strengths(ASTM C 1329 compliant) allow engineers to use some of a masonry's actual ability to resist bending and negative loads without failure--no more discounting any ability to resist pulling apart during design and code compliance phases, equalling cheaper/competitive masonry walls.

Nearly all commerical work I build now requires PCL type Mortars to achieve the same goal, fema shelters, or any public building that is considered worthy of being more disaster resistant.
Actually, 4th gen, ASTM C-270, C-91, and C-780 separate the sheep from the goats. ASTM C 1329 is just a get out of jail free card for engineers.
ASTM C 1329 and IBC 2103.7 standards for Mortar Cement is the guide lines manufacturer must meet when making Type N, S and M masonry mortars.
Look on the plan if you have to meet ASTM C 270 also, which is cement mix proportion requirements, like the mix should contain 2-1/4 to 3 parts loose damp masonry sand...
Lime amount should be for M Type 1/4, For S Type over 1/4 to 1/2, For N Type over 1/2 to 1-1/4 and O Type over 11/4 to 21/2.... and all that should produce mortar consistency with flexural strengths which will meet all the requirements of ASTM C 1329 and having Flexural Bond Strength- 28 Days minimum PsI: Type N 70 Type S 100 Type M 115.
I think what tscar is saying is that it is a standard that cannot be tested on site so it has no real world validity. IF it was just a proportioning standard then it would already be met by the other more typical standards which we are all familiar with
Maybe I'm wrong, i just re-read and saw it was pre-mix bagged goods
The intent and purpose of the standard is to promote an increase in bond strength and flexural strength, neither of which are accounted for by the previous standards. That is a good thing by itself.

As it is in the real world (and unlike the older standards which are based upon hundreds, if not thousands of years of empirical experience), the only way to get the desired bond and flexural strength is with additives to the basic components of mortar.

Technically this could be done on site just like color is sometimes added to mortar, but practically what it means is that it becomes a pre-mixed proprietary blend. As such, it has to be tested and that is the purpose of ASTM C 1329.

The problem is lab testing VS field testing and Engineers confusing the two. ASTM C 1329 makes no allowances for field conditions or testing, but neither does it explicitly state that performance in the field will differ from the lab results and that that is OK.

The same thing happens with ASTM C270, but only by engineers and architects not familiar with the standard. Once they are educated the issue goes away since it IS addressed in the standard.
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Here is the clip of what ASTM C 1329 represents. I don't know how you conduct the test in the field because ASTM is American Society for Testing and Materials.
Standard Test Method is defines the way a test was performed and the precision of the result. The result of the test may be used to assess compliance with a Standard Specification.


Right, Greg, it tests compliance of the manufacturer, tested in the lab. Then bonehead architects and engineers insist that field samples must meet the same criteria. There is no method for sampling nor testing of field samples.
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We are "field" tested twice daily. Testing agency gathers sample am then pm as sample leaves mixer. The agent places samples in vessels places date time tag on each places them in spare block they form in square 4 block placed side by side ends touching forming hollow area in the center of four. Three vessels per gathered sample. Agent then places plastic sheeting over the 6 vessels inside the 4 block and wraps caution tape around all blocks it also keeps plastic in place. Next day samples are gathered to return to lab. As we are obligated by contract to cover all masonry minimally 2' down we usually go 4'. I assume that may be the reason they cover collected samples to duplicate field process as closely as possible? We don't need to know the particulars as we are only required to provide samples. What happens after that and during collection is not in our job scope. Do know we have to meet minimum 2000 psi break test at 28 days. Our breaks have always been over most averaging between 2100 to 2200. Don't know if this helps any to clarify this standard. JDK.
This is a very good article to Read and Understand ASTM C 270 and C 780 articles... I think this is more related to what Heavyc said.
HeavyC @ Field test, the mortar cubes the tester is making are just being tested for compressive strength, not tensile...

Tscar, the ASTM 1329 provides standards for "mortar cements" that if properly used will achieve the stated minimun qualities, Without special additives, "regular' masonry cements plasticisers (limestone dust...etc) prevent most of those products from achieving any consistant tensile strength with out additional additives, (bonding agents, epoxies...)

The standards are confusing, and locally have lead the area archtitects to spec'ing only PCL mortars that are much harder to clean up and require more labor to keep in ready to use condition(tempering).
We do add Dry-Blok to our mix which is confusing almost contradicting as the Type-S Giant mix we use states waterproofing agent add on the bags. Confused by the need for double water proofing additives? We are laying 4" split face that claim to have waterproof mixed in to the batch or applied some where in manufacturing process of block. Again JDK
Redundancy seems to be the current tread in the modern masonry world.
We do add Dry-Blok to our mix which is confusing almost contradicting as the Type-S Giant mix we use states waterproofing agent add on the bags. Confused by the need for double water proofing additives? We are laying 4" split face that claim to have waterproof mixed in to the batch or applied some where in manufacturing process of block. Again JDK
I wonder how the old buildings ever made it 100+ years without all of the engineers in the world to tell us how to build bricks...
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