We are planning to pour a 20 x 35 ft driveway with a slope of 15 inches in 10 feet, 6 bag mix, 1/2 rebars 2 ft each way, 4 inches thick over compacted gravel.
We are not experienced with vibrating screeds, but we can rent one that has a honda motor and attaches to 2 boards. We are planning to get 2 – 20 ft 2x6s, add a little to each end and pour the whole width at once.
Since we will have to pour it drier, we are interested in using the vibrating screed.
Does this sound like a good plan? From the top to the bottom, right?
Replies
we dont even use vibrating screens on flat work
Why not?SamT
all yur CC is gonna move down hill...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
That's about a 7° slope. I don't think it's enough to make any difference.
But I'm not a concrete guy...
12.5%SamT
I don't have any experience with vibrating screeds, but I know that by hand I would not pour 20 feet wide, I'd throw in a temp screed down the middle and pour it in two halves. If your pour was flat I'd say use a plasticizer... then it would be easy to pour all 20 feet. On a slope it could be trouble.
How many guys will you have on hand?
We were just planning to do it with us two, thinking the vibrating screed would take up the slack. From what the consensus is it looks like it might not be a great idea. Normally we would put a pipe in the middle and rake it by hand, but since it will have to be poured drier - that would kill us raking it. I hear you have to have more solid forms for this too. If it's not going to work I'd like to find out before.
Two guys for a pour that size is a little light, at least in the beginning. Ideally I like two on the screed, one running the chute and one raking. If I have four guys total we can get the mud on the ground quick with some accelerator in it, then bullfloat and start finishing (one guy can leave when the last truck leaves). With two guys you probably don't want accelerator, and make sure you get your mud at 7:30 AM, or whatever their early time is. I assume you are doing a broom finish, so you can probably get away with it. It would be good to get at least one extra guy for the first few hours.
Sorry, I've got several questions about this for those that know.Is it that the vibration would be transmitted through the forms to the concrete already struck off (up hill) and gravity then would pull it down hill? I agree on the extra help - I think you're right. Is there any way to still pour it less than stiff (fairly workable)? We are experienced with concrete - just not slopes. Is floating (from the side) going to cause it to creep? (again this is 1 1/4/foot slope)Will it help that there is a compacted gravel base rather than sand (to keep it from drifting downhill)?Should we have a form with notches over the rebar to help hold it in place between trucks? Yeah, it will be a broom finish. We won't be getting out on it.
-I would not attempt to pour that much concrete with just two people. You should have someone dedicated to the bull float working right behind you.
-If possible, I would pour uphill instead of downhill..that way your concrete doesn't want to follow the screed downhill.
-There are screeds and there are screeds....some of the smaller ones will not do the trick on stiff concrete, especially on a span like that. In my opinion, that is way too wide to be using 2x material for a screed board.
-If it is hot, that much stiff concrete could easily get away from you if you don't have enough help.