That slab in Austin that spider-cracked after 6 hours

Poured a 12x20 patio in 95 degree heat last August and forgot to wet cure it, had hairline cracks spreading by dinner time, anyone else ever salvage a bad cure with a sealer or did I just learn the hard way?

3 comments

3 Comments

the_emery22d ago

Honestly, I've been there with a slab that looked like a map of Texas before the concrete even fully set. You can try a silane or siloxane sealer to lock out moisture and stop the cracking from going deeper, but it won't fix the ones already there. Ngl, if the cracks are just hairline and the slab isn't shifting, a quality penetrating sealer might buy you a few years. I've seen guys flood the surface with a thin-set sealer right after a bad pour and it helped blend the cracks a bit, but they never really disappear. Tbh, unless you grind it down and epoxy the whole thing, you probably just learned the hard way.

jasonf1722d ago

Three days after my last pour I had a crack that looked EXACTLY like the San Andreas fault line, complete with a tiny offshoot that made it look like Fresno. I tried the siloxane route and honestly it just made the cracks shiny so they stuck out even MORE. My wife said it looked like I was trying to make modern art out of my driveway.

adamr1422d ago

You mentioned "silane or siloxane sealer" for locking out moisture... but those two actually work different. Siloxane is more for above-grade stuff like walls, and silane penetrates deeper into the slab. You want a silane-based one for a horizontal surface like a driveway, especially if it's already cracked. And yeah, you're right about it not fixing the existing cracks though... once they're there they're not going anywhere. I've had good luck with a low-viscosity epoxy injection for the bigger ones, but that's a whole other can of worms.