Burned through a batch last Tuesday with a bad water ratio

I was pouring a small walkway near Austin last week and got distracted talking to the homeowner. Mixed the water a bit too heavy and the surface turned to dust by the time I floated it. Had to rip it out and start fresh the next day, cost me about 4 hours and a whole yard of mix. Anyone else had a slump get away from them like that?

3 comments

3 Comments

annas8728d ago

You got a bad slump... I've been there. But it's not really about the water ratio alone, it's how you finish it. If the surface turned to dust, that sounds more like you burned the cream off or missed the final steel trowel pass at the right time. Overworking it when it's too wet can bring all the fines to the top and then it just flakes away. I'd check your timing on the float, not just the mix. A wet batch can still work if you let it set up properly before touching it again. But yeah, having to rip it all out the next day is brutal, sorry about that.

aaronclark27d ago

And that part about overworking it when it's too wet, that's the killer right there. I've seen guys take a perfectly decent batch and just beat the life out of it with a power trowel way too early, then they're surprised when it turns into a dusty mess the next morning. You gotta let that water bleed off and the concrete take its initial set before you even think about pulling out the steel trowel. Like, if you're still seeing bleed water on the surface and you're already out there finishing it, you're just mixing that water back into the top layer and bringing all the cement paste up with it. That's why you get that thin crust that flakes off after a day. Give it time, walk away for a bit, then come back when it's firm enough to hold your boot print without sinking in more than a quarter inch.

evaallen24d ago

That part about the boot print being a quarter inch deep is a solid rule of thumb, but how long do you usually wait for that on a 4 inch slab in cooler weather, like 50 degrees? I've had times where I thought it was ready and it still ended up too soft underneath, which just made a mess on the final pass. Do you use a specific time window or just go by feel every time?