Corrosion Protection for Rebar, Research Paper Example

Introduction

With the ever growing need for infrastructure and housing for the citizens, many governments have put huge sums of manpower and resources to push this noble course forward. However, many obstacles have always undermined this idea. The world’s population is also growing at a tremendous rate and this calls for drastic measures, if the growing human race needs to be sustained. It is important to note that good infrastructure is the driving force behind the global economy. In essence, infrastructure comprises of so many things which include, roads, bridges, buildings and much more. Unfortunately, corrosion has been a nudging problem for many years to engineers in this industry and is high time this problem is addressed as done below.

What is corrosion?

Davis (12) asserts that corrosion is the process through which some material e.g. metals undergo some form of chemical reaction that disintegrates the engineered material in the given matter into its constituent atom. A good example of corrosion is the formation of iron oxide; this usually culminates after iron atoms have been oxidized. Of all materials used in building and construction, metals are the most affected by corrosion; metals usually corrode after reacting with an oxidant such as oxygen. In its simplest form, corrosion can be defined as the wearing off of some parts of a material because of some chemical reaction (Davis 18).

How and when does corrosion take place?

Any material kept under unfavorable conditions will most likely be affected, let us use metal as an example. When metals are constantly exposed to moisture, corrosion will certainly occur; this is because the iron atoms found in most metals deteriorate after being exposed to water and oxygen. A corroded metal is usually reddish-brown in color (Rust). Other material such as ceramics experience corrosion after being exposed to ultraviolet rays, these rays are usually emitted by the sun. Corroded ceramics are characterized by weakened polymers and discolorations.

Where does corrosion take place?

Depending on the kind of material one has or uses, corrosion will always occur any where, so long as the given material is not kept under the required conditions. Metallic materials and structures should always be kept far away from oxygen and moist environments. Failure to observe this simple precaution, metallic structures will never last for the expected duration as stipulated in the initial stage of its development.

Rebar

A rebar, commonly referred to as a reinforcing bar is a steel slab used in strengthening stone and concrete structures. Although concrete is strong in compression, it is somewhat fragile in tension, because of these characteristics, a rebar is used with concrete to cover for the mishaps of concrete. A rebar is commonly used with concrete because it has the ability to reduce the tension characterized with the use of concrete as a building material (Heyfield 23). However, the use of rebar comes with its limitations, the rebar is expensive, it requires additional labor and lastly it can corrode easily.

How to prevent rebar corrosion

Since rebar is mostly used in reinforcing structures like bridges which are always built in severe environments, precaution should be taken.  Most bridges pass over water bodies which are characterized with moisture and salt, it is important to note that moisture and salt facilitate quick corrosion. These oxidants can reach the rebar placed within the concrete in two ways:

• By penetrating the concrete

After a long exposure of the concrete material to the environment, many changes will definitely occur. The surface will ware off after being rained on, this definitely creates some loopholes into the concrete that corrosion would find very easy to penetrate.

• By passing through cracks

During the drying process, the concrete material usually cracks from the high heat emitted by the sun. The cracks usually create an easy way for corrosion to penetrate and attack the steel. After the steel is covered with rust, the volume of the rebar will increase ten times more than its initial volume. The increase in the volume of the steel expands the size of these cracks, making them lager; the ending result will be the delimitation and spilling of such structure (Heyfield 45). Drastic measures should be taken at this stage because the strength capacity of this structure might be compromised.  By understanding the corrosion process, efficient measures should be taken to prevent this adversity. Ping (13) claims that the average life span of a typical concrete bridge vary from one place to another, in Ontario, the average life span of a concrete bridge is 75 years. This period is long enough for a corrosion to occur, it is therefore important that engineers find special ways of preventing this trait that has dogged the building industry for long.

Epoxy Coated Rebar

Since many governments spend huge sums of money in repairing and maintaining bridges, drastic measures should be taken to counter attack this menace “corrosion”. Through hard work and dedication, ECR is here and it is going to help us cub this problem. By preventing moisture and chloride from reaching the steel’s surface, Epoxy reduces corrosion significantly. The technology behind this method is very simple; Epoxy does not change the concrete’s load capacity (Ping 34). It only modifies the development length of a given structure hence causing minimum problems. This is evident in many structures where this technology has been used, only a handful of problems are evident.

ECR manufacture

First off, clean the steel, thereafter heat the steel to the require temperatures before applying the Epoxy coating matter. Allow the coating applied to cure before inspecting it to confirm its readiness for use. However, the coating process is very delicate, powder coating and equipment configuration should be standardized (Rena 56). Although ECR is the best option in preventing corrosion in Rebar, other strategies can be applied to achieve the same goal. These strategies are discussed below in summary:

• Surface sealers

Membranes and other materials are used to provide an impervious layer between the steel and the external corrosion stimulants.

• Concrete barrier

Although this method can increase cracking propensity, it has proven to be effective. This approach is characterized by slowing down the ingress of the chloride to the rebar.

• Steel coating

By galvanizing the steel with zinc, a barrier will be formed between the environment and the steel. This galvanized matter will act as a sacrificial anode for the rebar.

Conclusion

After many years of handwork and dedication, the building and construction industry has made immerse steps towards combating the problem of corrosion. Many countries have adopted the above methods to fight corrosion and the results are evident. The cost of building and maintaining our infrastructure has reduced significantly.

Works cited

Davis, Richard. Corrosion: Understanding the Basics. New York: ASM International, 2000. Print.

Heyfield, P.C. Corrosion Prevention in Concrete. Birmingham: IMI plc, 1986. Print.

Ping, Gordon., and Beaudoin, J. “Research in Cost Effective solutions for Corrosion Prevention and Repair in Concrete Structures.” Construction Canada. (2006):36-39. Print.

Rena, Evans. Metallic Corrosion: Passivity and protection. Toronto: Edward Arnold & Co, 1945. Print