Old timer at the supply yard dropped a gem about cold weather mortar mixing

I was picking up a pallet of block on Tuesday and this retiree hanging around the yard told me I was 'fighting the water instead of using it' when I complained about slow set times. He said to heat my mix water to 140 degrees before adding it to the dry ingredients, never the other way around. Tried it on a small retaining wall job yesterday and it cut my freeze delay by almost half. Any of you guys do this regularly or is there a better trick for winter work?

2 comments

2 Comments

christopherwilson8d ago

fighting the water instead of using it" is exactly what you're doing when you heat it up. You're just asking for trouble with hot mix water. That 140 degree water is gonna flash set on you if you're not careful, especially with modern cement blends. I tried that trick once and ended up with a batch that went off in the mixer before I could even get it placed. Ruined the whole pour. Plus if you're adding hot water to cold dry mix you get uneven temps in the batch and weak spots. Cold weather work you gotta slow down and use accelerators like calcium if you need the speed, not mess with the water temp physics. Keeps it simple and predictable.

felix_hayes648d ago

Man that's rough, I feel for you. I had almost the exact same thing happen a few winters back when I was trying to get a garage slab done before a freeze hit. Thought I was being smart heating the water up to around 120 and it set so fast I barely got half the load placed before it was too stiff to work with. Had to rip it all out and start over, cost me a whole weekend and a bunch of material money. Your point about the uneven temps is dead on too, I never thought about it that way but it makes total sense why you'd get weak spots. Calcium is the way to go for sure, just takes a little more patience but at least you know what you're getting.