Concrete hydration retarders and awakeners

[kfc510]

Out here in the Santa Fe desert helping on a pour, the concrete guy got lost (and was sent from Albuquerque to begin with).

Mud's been in the truck for more than two hours at this point. Apparently they added a retarder to "put it to sleep" and will add an accelerator to "wake it up" when it gets here, if it ever does.

I did a little googling, and it seems to be a legit practice, but not one I'm familiar with.

http://www.curtis-enterprises.com/ht...tard%20930.pdf

Anything I should be on the lookout for?

kevin

p.s. If they can charge us standby time, shouldn't we be able to charge THEM standby time???

[David Meiland]

I have used both, but would be cautious about the accelerator. In my experience, that's for guys who want to finish a slab NOW and have the skilled manpower on hand to deal with concrete that's going off quickly. On a hot day with the sun shining, I think it's going to go off without any chemicals.

If I'm doing a small slab on a cold day and can only get an afternoon delivery, I would get accelerator, maybe. Read up on the issues with calcium.

[Ted S.]

If its made by Sika, and you follow the instructions and stay within the product limitations, you should be fine. Try and park the truck in the shade. 2 hrs is a long time, beyond that allowed by many specs. So that product must be some good stuff.

I'd wonder why the concrete was sent from the plant before the labor was onsite, sounds like something I would do.

[Ted S.]

I agree with David on the accelerator, and his reasoning.

[kfc510]

The laborer (me lol) was on site the whole time, the dispatcher or the driver screwed up. The Santa Fe plant was closed today, so they sent it from Albuquerque, an hour's drive under the best of circumstances. Then the driver claimed hwy 25-285 was closed, after I had driven back from town that very way this a.m. Hence my desire to charge standby time to THEM...

We didn't add any accelerator, and it is popping fast. Wind is coming up too. It'll crack. It's just a base slab for exterior tile work, so no worries. I'm glad I don't do finish crete work out here.

edit to add: don't actually know what retarder they used, Sika came up on my google search so I linked to it. I also have a fair bit of confidence in Sika products.

No idea if they used whatever product they used according to the directions, don't have a lot of confidence in them after the way it went. I would easily believe the driver stopped at an Albertson's and picked up a 5 lb. sack of sugar and tossed it in there...

[Ted S.]

So you got hosed by the truck, nothing new there. I thought it was a lost concrete sub.

I would say you have the right to refuse the load, but you are placing it now so I guess the guy you are helping owns it.

I guess the next Google search is "crack isolation membrane..."

[kfc510]

So you got hosed by the truck, nothing new there. I thought it was a lost concrete sub.

I would say you have the right to refuse the load, but you are placing it now so I guess the guy you are helping owns it.

I guess the next Google search is "crack isolation membrane..."

Yup. Ditra, Ditra, Ditra.

We talked about refusing the load but I'm aiming to leave town today, so it would have gotten complicated. It actually looks to be curing fine as long as you hose it down approx every 3 minutes...

[David Meiland]

I would keep misting it frequently for several days........

[kfc510]

I would keep misting it frequently for several days........

Me too. My buddy whose house it is is a little less into soaking curing concrete than I am. He usually goes the spray-on sealer/cure, or plastic sheeting, or in this case a bunch of shipping blankets. The blankets might work great, if he kept them damp.

It's just a base for a tiled "portal", and it's got bar in it, so even if it cracks it's not a big deal, it shouldn't move around. As Ted suggested, Ditra will go down before the tiles.