Concrete Driveway
Concrete Driveway
(OP)
My project includes adding a narrow strip of concrete (1.5' in width) to an existing drive fabricated of 12' x 12' panels, 4" thick, rebar on 12" centers. In order to minimize potential cracking, what sort of enhancements (high strength concrete, 5" or 6" thickness, extra reinforcement, etc.) might be considered? This drive is for auto traffic of typical (say 4000 lbs) size at low speeds.
Thanks to all for their helpful advice.
Thanks to all for their helpful advice.





RE: Concrete Driveway
RE: Concrete Driveway
RE: Concrete Driveway
RE: Concrete Driveway
Have some very good and compacted backfill
Extend the backfill beyond the edge of the new slab
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Concrete Driveway
I would prefer to attach new pieces to existing as not wanting to create a problem on existing pavement which is crack free. If the new piece is doweled in would a control joint be added where the two pieces join?
RE: Concrete Driveway
RE: Concrete Driveway
As oldest guy stated, the slab is skimpy for installation of rebar. For welded wire reinforcement, the Wire Reinforcement Institute recommends steel placement 2 inches below the surface or within the upper third of the slab thickness, whichever is closer to the surface.
Unless the existing slab has an existing trowel edge, the new joint will not be neat.
Consider darthsoilsguy2 recommendation.
RE: Concrete Driveway
So to control the cracking, would a thicker slab (5" or 6") in the narrow section be beneficial? Also, is the type or selection of concrete significant?
RE: Concrete Driveway
good compacted gravel base
no reinforcement is probably needed
standard Class A (3,000 psi) concrete is adequate
RE: Concrete Driveway
In some areas, for driveways, aprons, garage floors and some sidewalks, the unwritten standard is 4000 psi with 5% air for durability. Even if it is not written, a supplier may refuse to deliver something less is they sense it falls into those applications. The supplier does not want to get into a hassle later if it is not a contractor with good practices. - The sale of a load or two is not worth the later problem of the an undeliverable load of concrete.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.