I was shocked to learn concrete curing temperature changes the final strength by almost 50 percent

I was reading through an ACI guide last week and found out that if you pour concrete when it's below 50 degrees F, you can lose up to 50% of your 28-day strength if you don't manage the cure right. I always knew cold weather was bad but I didn't realize the drop was that big. We did a driveway pour in Denver back in November and I'm wondering now if we should have waited longer. Has anyone else seen big strength differences from winter pours?

2 comments

2 Comments

martin.riley4d ago

Whoa wait, 50 percent? That's way bigger than I ever thought. I bet that Denver pour is definitely gonna test that theory. I did a small garage slab up in Montana a few years back when it dropped below 40 right after we finished and I swear that thing still has cracks you could drop a quarter into. I really should have looked into the curing blankets more seriously but figured a little tarp would do the trick. Nope. You don't forget a mistake like that when you're staring at it every morning.

nguyen.angela4d ago

Hearing "below 40" right after a pour makes me wince every time. I helped a buddy with a sidewalk in Boise where the temp dropped to 38 overnight, and we just crossed our fingers. Even with blankets the next day, there are these hairline cracks that snake all the way across. I wonder if the Denver crew is going to regret skipping the heated blankets or if they have some magic trick up their sleeve.