Slabs thicker than 5 ” should have a web of rebar to prevent it from cracking. Patios near buildings commonly bridge backfilled ground and should have added tensile strength, as should those on slopes or weak ground. Small concrete slab, walkway, and concrete driveway in addition are a couple extra ideas to keep in mind.
Instead, you will need to use fiber mesh concrete. If you need to lay a thin layer of pavement, rebar won’t work . Again, you will need to use fiber mesh concrete. Spalling is when the surface of the concrete is heated, forms steam, and then the surface explodes.
Another thing we wondered was; do you need rebar in concrete footings?
One way to think about this is including rebar in a concrete footing means that you can reduce the risk of the concrete being pushed and pulled apart – cracking – from ground force pressures. Knowing this, it is generally a good idea to use rebar in footings for any structure. However, it is not required in many cases.
This begs the inquiry “Why are rebars protected by concrete instead of soil?”
In addition, concrete has a basic rather than acidic chemical characteristic, which protects the rebars. Soil could be a different chemical challenge for rebars, so concrete is a good method to avoid direct contact, as mentioned by others.
Use of plastic or concrete spacers is allowed to keep rebar off the ground when pouring. If there is a poured concrete or masonry wall on top of the footing, you’ll need #3 or greater vertical rebar at a minimum of 48” on center. These bars have hooks at the bottom extending laterally towards the edge of the footing.
Sure, you can use other metals to bury into concrete to make it stronger. But all metals have there own set of strengths and weaknesses when used for this purpose. For instance steel has tensile strength and is flexible enough to give with dynamic loading, but is subject to corrosion.
How long will rebar last in soil?
I would guess that rebar would survive anywhere from 10 years to 2000 years, depending on the soil chemistry. It will rust if it’s exposed to water, salts and oxygen – fairly fast in a tidal marine environment – but it’s a solid steel rod with small surface area to volume, not a cable or thin sheet.
However, if it IS rebar WITH a wire, then the rebar actually should be encased in a buried pillar of concrete (see Johnson’s comment below). But if it is NOT so encased, then a ground rod should be driven into the ground somewhere nearby, and the wire moved to it.
What is rebar and why is it used?
Concrete is made by mixing cement, sand and aggregate stone with water. Understanding rebar, base material, wire mesh vs rebar, compressive vs tensile strength, rebar provides additional tensile strength to a concrete structure, rebar sizes, the thickness of concrete, rebar positioning, and types of rebar in addition are a few additional items to investigate.
Rebar will only strengthen finished concrete if it lies midway through the thickness of the concrete, so consider positioning when choosing rebar. The rebar should be elevated on small blocks, called chairs, that position it correctly. Stone or waste concrete are suitable choices for chairs.
Does rebar Rust in water?
It will rust if it’s exposed to water, salts and oxygen – fairly fast in a tidal marine environment – but it’s a solid steel rod with small surface area to volume, not a cable or thin sheet. Most of the time, a piece of rebar sticking out of the ground is embedded in a block of concrete below the surface.