**1. Introduction**

The term corrosion originated from the Latin word corrodere, meaning gnawing to pieces. Corrosion is the process of material deterioration due to electrochemical interactions with the surrounding environment.

Since ancient times, metallic corrosion has been a problem in the utilization of metals. Nearly all the metals present in nature are in the metal compounds, such as oxides, silicates, and carbonates. Hence, after the extraction of metals, these metals tend to become naturally occurring metal compounds once in the environment.

One of the most known examples of corrosion is rusting of iron. The rusting of iron is the formation of iron oxides. The extraction of metal iron from its iron oxides present in the earth's crust is just a reverse process of the rusting of iron. The reaction of iron with oxygen to form iron oxide is a reversible reaction.

Considerable efforts had made to develop corrosion prevention measures such as metal doping and coatings of other metals, pigments, polymers, and organic materials. However, due to the limitations of these preventive measures, complete corrosion prevention is still unachievable. The main drawback of structure corrosion is that it leads to structure failure catastrophe. One of the well-known catastrophes is the sinking of the Titanic. The utilization of different types of iron in about 3 million

rivets in the highly corrosive seashore environment leads to the corrosion of rivet joints. These weakened joints aided in the catastrophe.

As the demand for high-strength and lightweight structures increases, metals become one of the most favorable choices for the structures.

Currently, modern infrastructures utilize different materials, such as metals, alloys, glass, plastic, wood, ceramic, silicate brick, and natural stones, increasing the corrosion prevention challenge. The benefits of the metal's diverse composition, structure, and chemical, physical and mechanical properties ease metal utilization for modern infrastructure, making corrosion prevention a challenging task.

A combination of incompatible materials in the environment leading to the decline in corrosion resistance and weathering resistance of the infrastructure will reduce the life of the infrastructure. There is a need for the corrosion protection of structural steel, especially for the reinforcements, load supports, and frames that have become extremely important to meet the demand of modern infrastructure having 100–120 years of service life.

In the following sections, we will focus on the corrosion causes in steel reinforcement, steel cables, and structural steel with the advantages and disadvantages of different corrosion protection techniques.
