DAE change their mind on winter mortar after one cold snap in Boise?

I used to be the guy who said you just add a little antifreeze and keep laying, no big deal. Then last November I was on a garage job in Boise and the temp dropped to 24 degrees by 2pm. My mortar started setting up in the board inside 20 minutes. I ended up with 14 blocks that had to come out the next morning, which cost me about $300 in labor to redo. My old boss had always told me type S mortar handles cold fine if you cover it. I dug through an old ACI book at the library and saw you're really supposed to keep the mortar above 40 degrees until it sets, no matter the mix. Now I run a thermometer in the sand pile and won't lay below 35 unless I tent it and add heat. Has anyone else had a pour go bad on a cold day like that?

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thead441d ago

The 40 degree thing is about the mortar temp itself, not the air temp, so a thermometer in your sand pile is only telling you half the story. You really want to check the mortar right out of the mixer since cold sand and cold water will drag it down even on a warmer day. Tenting and heat is the right call either way, that part you've got nailed.

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