Cold joint failure on a hospital floor slab finally made me switch from wet to dry cure

Last month I was helping pour a 40,000 square foot slab for a hospital expansion in Nashville. The GC always insisted on wet curing with burlap and soaker hoses, but we got a cold snap overnight and the edge curled bad, creating a huge cold joint. When we tested the cores, the tensile strength was 30% lower than spec. The structural engineer literally said 'this is why I specify curing compounds in my notes.' I've been team dry cure ever since. Has anyone else had a project saved by switching methods?

3 comments

3 Comments

sullivan.abby6d ago

Was the cold joint right at the edge where the curling happened?

the_lucas6d ago

Yeah, but "switching from wet to dry cure" isn't always the magic fix people make it out to be. I've seen plenty of jobs where a curing compound was put on wrong or too thin, and the slab still cracked worse than if they'd just kept the burlap wet. I think that cold joint could've just as easily been from poor timing or a bad mix, not the cure method itself.

simon_sanchez584d ago

Damn, 30% below spec? That's rough. I'd be losing sleep over that number for weeks, especially on a hospital slab. Sounds like that cold snap was the real culprit though, not just the cure method.