When looking at the deterioration the slabs around your home experience, you might notice that your slabs are not reinforced with rebar. Typically, concrete slabs used for walkways, driveways, pool decks, and other areas of your home are only four inches tall and are not reinforced.
If your concrete is sinking, then you might be wondering if you should replace your settled slab with one that has rebar. Unfortunately, rebar does not stop a concrete slab from settling. Replacing and repouring a brand-new slab is a lot more expensive than simply leveling it. It’s also a waste of time because you’ll be dealing with the same settling issues in a few years despite the addition of rebar.
What It Does
Rebar is used to reinforce concrete because it has great compression strength but poor tensile strength. Compression strength means that concrete does not lose despite supporting a lot of weight. Tensile strength measures a material’s ability to resist breaking under pressure. Poor tensile strength is the reason concrete breaks so easily when hit with a hammer: Because the pressure is concentrated in one spot, the concrete cannot take the hit and breaks in half.
Rebar is meant to increase concrete’s tensile strength by absorbing pressure. The rebar redistributes pressure evenly throughout the slab so that it’s not concentrated on one point. This way, the concrete can take on heavier loads and withstand a lot more.
What It Doesn’t Do
The reason rebar does not help in preventing concrete settling is because settling has nothing to do with a slab’s tensile strength. Regardless of how much pressure it’s able to withstand, if it doesn’t have a solid foundation, it will sink. Therefore, it’s futile to try to add rebar to the slabs around your house just to avoid settling. If there’s soil displacement, there will be settling.
What rebar can help with is concrete cracks after there has been settling. If the slab has settled, then there’s a chance it will break apart because it cannot distribute pressure properly on an uneven base. Rebar can help the slab stay strong and not crack. Still, adding reinforced concrete to your home’s pavement is not worth it when you can just use polyurethane foam injections.