Is Rebar needed in a driveway?
The best option for your driveway reinforcement is welded wire mesh/fiber mesh. The mesh consists of galvanized panels of welded wire. Heavy gauge welded wire mesh panels can provide reinforcement for driveways that are not routinely driven on by heavy vehicles such as construction vehicles or industrial trucks. Mesh is typically used by contractors who pour driveway concrete to a thickness of 4 inches because it is a thinner reinforcement and less expensive than rebar.
Rebar is almost never installed correctly in driveways, costs more money, and provides no benefit on account of its inevitable incorrect placement. If the steel is un-coated, it will rust and corrode on account of the wet and alkaline environment. Rusting steel expands, causing the concrete to crack, leading to more water infiltration, leading to faster rusting, leading to more expansion, leading to wider cracks. If the steel is epoxy coated, it never bonds to the concrete and does not do anything. Leave the steel out and make the slabs an inch thicker. Proper control of joint spacing and sealing is important.
If you can afford a Rebar driveway, it will need to poured at 6 inches minimum. This is because rebar is comparatively thicker than galvanized mesh reinforcement. The proper way to use rebar reinforcement is to ensure that it is laid in the center or slightly above the center of the slab's thickness(18 inches on Center, crossed). To do this, concrete pros prop up the rebar grids on special metal or plastic supports, called "chairs." It's also possible to use bricks and other scrap material for supports, but this can create weak spots in the slab. Rebar grids are constructed by laying the pieces of bar in a perpendicular pattern, with even spacing. The bars are tied together at each intersection with metal wire. The edges of the grid should be kept at equal distances from all sides of the slab, and the minimum coverage of concrete must be maintained throughout the slab.