Concrete slab control joints
Concrete slab control joints
(OP)
I am working on an elevated concrete tunnel, for which the floor must meet "superflat" requirements. The tunnel width is 20' and is 250' long. The floor is a cast in place concrete, one-way slab with reinforcing in two mats (each direction) top and bottom. Is it at all realistic to try to cast this slab without control joints?





RE: Concrete slab control joints
RE: Concrete slab control joints
Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that them like it
RE: Concrete slab control joints
RE: Concrete slab control joints
Can't quite picture what "(each direction)" means, unless it just means there are two mats with reinforcing steel equally spaced in each direction. Regardless, it will crack, and the crack spacing will depend on the depth of the slab, the mix design and exposure conditions.
Greg
RE: Concrete slab control joints
Dik
RE: Concrete slab control joints
Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that them like it
RE: Concrete slab control joints
RE: Concrete slab control joints
What sort of environment is the tunnel in? Subject to thermal movement? You will have to break it down into a minimum of half a dozen sections and throw in a pile of rebar to minimise crack widths. If a true 'super flat' floor is required, you will have to take extraordinary care at the joints.
Dik
RE: Concrete slab control joints
As Dik mentions I was hoping to use a lot of extra reinforcing to minimize/eliminate control joints, but figured that this distance would be too far to go. Hariline cracks would not be an issue. The tunnel is unheated/outdoors and will be subject to thermal movements to make matters worse.
Thanks all, particulary Ron, very insightful....
RE: Concrete slab control joints
Good Luck!
Dik
RE: Concrete slab control joints
These guys are always looking for good example projects, so I'll bet they'll be helpful.
RE: Concrete slab control joints
If the slab was subject to heavy traffic, this may not work though.