Can Rebar Rust in Concrete?

Rebar is the reinforcing metal rod that’s used in concrete during construction. It increases the overall structural strength of the concrete. Unfortunately, since rebar is made of metal, it is susceptible to rusting, even in concrete.

When the rebar starts to rust, it starts to expand. This can affect your concrete directly. Concrete naturally lacks tensile strength, and when rusted rebar in concrete starts to expand, it becomes unable to bear loads and results in cracking and serious damage. Your concrete becomes weak and structural fatigue ends up damaging it for good.

can rebar rust in concrete

Why Can Rebar Rust in Concrete?

There are many reasons why rebar rusts in concrete and eventually damages it. Here is a list of some of the top reasons that cause rusted rebar in concrete:

Shrinkage Cracks

Concrete is a mixture of cement and water, and it’s poured onto surfaces in liquid form. This liquid starts to harden as it dries. When concrete is poured, it has an excess amount of water. As the concrete mixture continues to harden, the excess water is lost. In losing the excess water, shrinkage cracks occur. The more water is added to the mixture, the more shrinkage cracks you will have. Larger shrinkage cracks can reduce the life of your concrete, and they allow moisture to enter. This moisture comes in contact with the rebar used inside the concrete as reinforcement, resulting in rusting. When rebar rusts, it can expand to four times its size, which leads to damaged concrete.

Improper Coverage

In most cases, the rebar needs to be covered with 3 inches of concrete. A dispositioned rebar may not get the coverage it needs to stay put. If rebar gets improper coverage, it can leave the rebar exposed to the environment, resulting in rusting.

Furthermore, if the concrete is not placed correctly, it can leave rock pockets. This usually happens because of less water content in the concrete mixture. The rock pockets tend to expose rebar, which results in rusted rebar in concrete.

Signs that Show Your Rebar is Rusting

Always be on the lookout for any signs of rusted rebar in concrete to avoid permanent damage. It is really easy to spot whether or not your rebar is rusting or not.

The first thing that you need to look for is any rust marks near cracks of your concrete. If you see any rust marks, it’s because your rebar is rusting.

Another sign that determines rusted rebar in concrete is square or rectangular patterns on the cracks. This signifies that your rebar did not get adequate coverage and is exposed to moisture.

Get Professional Help

As soon as you spot signs of rusted rebar in concrete, call in a team of experts and seek professional help. You can contact Snappy Pro Wash for all kinds of repair and maintenance related to rusted rebar.

Ask The Seal
Snappy Pro Wash is a BBB Accredited Roof Cleaner in Estero, FL

Recent Posts

What is good for Removing Rust on Concrete?

Here are some ways that will get rid of rust stains from concrete for good.


Can Rebar Rust in Concrete?

When the rebar starts to rust, it starts to expand. This can affect your concrete directly.


What is Soft Washing Your House?

There are countless benefits of soft washing your home. Here's everything you need to know about "What is Soft Washing".