Tried rapid-set concrete in 40 degree weather and it totally surprised me

Honestly, I always avoided pouring in cold temps because everything I read said it would fail. Last Tuesday we had a small sidewalk job in Denver and the crew was behind schedule, so we used a rapid-set mix with accelerant instead of waiting for spring. It cured hard enough to walk on in 4 hours, which I did not expect at all. The catch was we had to use heated water and cover it with insulated blankets overnight. Has anyone else pushed cold weather pours with accelerants and gotten away with it, or did I just get lucky?

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the_blair26d ago

and honestly it sounds like you got lucky as much as anything. The heated water and the insulated blankets are doing way more heavy lifting than the accelerant is, and in Denver you had the sun working for you even in the 40s. I've seen guys skip the blankets for a small job just to save time and come back to a surface that looks fine on top but crumbles underneath a week later. The fact that it held up for you is great, but 40 degrees is right on that edge where one cold snap overnight or a windy stretch can turn your nice sidewalk into a cracked mess. I wouldnt call it a win for cold pours in general, more like you managed all the variables perfectly. Next time you get a cloudy day with a breeze and no ability to heat the water, come back and tell me it still worked out.