Cold weather Masonry 2

[BurgoEng]

I'm trying to determine if a masonry foundation wall for a warehouse building that was installed the day that a 2-day cold spell hit, is acceptable or not. I dont' beleive any measures were taken to keep the wall warm (blankets, heaters, etc...) as is stated should be done in the ACI 530 manual.

Is there any way to test the mortar/grout/construction after the fact, if no samples were taken the day of? Should I advise to redo the work?

 

[COEngineeer]

they can drill a 3" sample hole and take sample for the lab. Contact a QC QA testing company. They might have different method. Make sure the sample is taken from the course that doesnt have steel in it.

 

[concretemasonry]

Drilling any samples would be a waste of time since the subsequent handling and curing would mask any real properties. It could only be a measure of the approximate ultimate strength of the mortar. Also, forget about the AIR temperature when looking back and try to estimate the temperature of the masonry mass itself.

Since you referred to ACI 530, you have some sort of a masonry foundation. The strength of the mortar is really not a major factor in the compressive strength of a masonry wall. At the time of laying, the most important factor, workability (as addressed in the appendix of ASTM C270), has already been determined. Durability of the mortar would be the question.

Your concern would be the temperature of the mortar over the few days after construction (which you cannot determine)since the strength of the masonry units is already fixed by factory manufacture. Another factor would be the amount and temperature of grout (if any). Since there was no wall protection, the general practices for cold wether were not followed or enforced. Key items would be mortar temperature (effected by sand and mixing water conditioning) and the amount of protection provided to the units before and after laying. If the units were above freezing, there is a large amount of thermal inertia that permits cold weather construction.

If the mortar did not freeze while saturatated, there should not be any descernable effect. The heat of hydration generated by combining the water with the cement compounds provides some additional benefits. Covering, even with poly, provides protection from premature cooling of the wall.

It is fortunate that masonry is very adaptable to cold weather construction. Last week, I visited a site where they were laying high 12" hollow block walls at 15 degrees (after 3 days of colder weather) within the recommendations for cold weather construction.

I doubt if you have any substantial loads on the walls to justify the wall thickness, unless you have lateral soil loads. I have seen 4500 psi prisms built with 1900 psi mortar, so compressive strength is not a problem. There is always the age-old question whether mortar holds units together or keeps them apart. Justifying the construction now in place is the challenge.

Any addition information that would permit an accurate opinion of the project would be helpful.

Dick

 

[dik]

concretemasonry... a short anecdote... one building I was looking at in Lindsay, Ontario had soft mortar. It was cold (-20C) and the hoarding was improperly done... put my pocketknife into the mortar joint and I could easily embed the blade in the joint... I mentioned to one of the masons that the wall should be enclosed and heated and that the mortar was still plastic and could freeze... He said not to worry, that the wall had been erected the day before...

Dik

 

[boffintech]

Why is the onus on BurgoEng to prove that the work fails to meet the minimum requirements? The contractor failed to follow accepted standard masonry construction practice required by code and contract. ACI530 requires masonry protection in cold weather specifically to prevent the EOR and the owner from wondering if the work meets code and contract requirements.

Let the contractor figure out how prove the work meets the contract requirements or let him redo it. The contractor needs to perform his own quality control.

 

[BurgoEng]

From the info I have been given after i posted the question, the contractor supposedly did "something" for the cold, and they are seeking their own independent company to verify the work is ok. I am not sure quite how this came to us to figure out, but as of now, we don't have to provide any verfications.

Thanks for the help.