Saw a video that changed my mind about wet curing

I always thought wet curing was overkill for flatwork. Been doing this 12 years and never bothered unless the spec called for it. Then I watched a guy on YouTube from the American Concrete Institute break down the numbers. He showed that concrete left to dry out loses about 50% of its potential strength in the first week. I ran some tests on a driveway I poured last month in Phoenix where it hits 105. I covered half with wet burlap and kept it moist for 5 days, left the other half to air dry. After 28 days the wet cured side tested almost 1,500 psi higher. That blew my mind. Has anyone else seen big strength differences from curing methods on their jobs?

2 comments

2 Comments

elizabeth_gonzalez5d ago

That part about losing 50% potential strength in the first week really stuck with me too. I had a similar experience back when I was doing a big warehouse floor outside Houston. The specs said curing compound but the boss wanted to save money and just let it dry. We ended up with this weird spiderweb cracking on about half the slab after two weeks. We had to grind it all down and overlay it with epoxy just to hide the mess. Probably would have been fine if we had just kept it wet for a few days like normal people.

shah.olivia5d ago

My buddy had almost the exact same thing happen on a parking lot job outside Austin a few years back. The contractor he was working for decided to skip the wet curing to save a few days, and they ended up with those same spiderweb cracks all over the place by the end of the first week. They tried to patch it with some quick fix stuff but it kept coming back (like a bad penny). Eventually they had to tear out a whole section and repour it, which cost way more time and money than just doing it right the first time. He still talks about that job whenever anyone brings up curing, ha.