mixing fast set concrete

[Bope]

I am back to trying J bolts for my pergola project. I am actually going to pour the concrete tonight. I am using fast set concrete hoping it will be cured enough in 24 hrs to tighten the j bolts and add tapcons. Any tips on mixing the fast set so that I still have time to set the j bolts? How much water for a 50lb bag of concrete?

[MstrCarpenter]

I am back to trying J bolts for my pergola project. I am actually going to pour the concrete tonight. I am using fast set concrete hoping it will be cured enough in 24 hrs to tighten the j bolts and add tapcons. Any tips on mixing the fast set so that I still have time to set the j bolts? How much water for a 50lb bag of concrete?

I use exactly 5" in a drywall bucket for two 80# bags. Same for the high early strength concrete. The first batch is usually a little dry because the little bit of cured concrete in my mixer absorbs some of the moisture. With only a single 50# bag it's tough to get an exact amount; the math says I should start with 1-1/2" for a 50# bag. If it's too dry, add in increments of about 1 once. Too dry to too soupy is a very small amount of water.

If you're using hydraulic cement, a little soupy is fine with a form; about as thick as you can mix with a drill without extraordinary measures to keep the bucket from spinning.

[crokett™]

with fast set I follow the directions on the bag. Most times they tell you to mix it in the hole. you'll have about 15 minutes before it starts to set. I fill the hole 1/3 with water - I have clay, this works, if you have sandy soil it might not - dump the bag in, then add a bit more water as needed. I use rebar to mix/get the water down into the concrete, then push the jbolt in and use the rebar to settle the concrete around the jbolt. I use the face of a piece of scrap 2x4 to float the top level and smooth.

[brianwelch]

http://www.concreteconstruction.net/how-...retarder_o
Use at your own risk!
We used to mix sugar and/or salt into fresh concrete as way of preventing concrete cure in case of a form blowout...

[Bope]

The bag did say 2.5qt per bag. I was mixing in a wheel barrow and it seemed to be a nice mix. The j bolts are set and the patio contractor is pissed I didn't have the actual posts installed. So quick work tonight to drill for the tapcons and get the posts plumbed.