Corrosion Resistant Concrete
Corrosion-resistant concrete is made with special materials and techniques for optimal performance in corrosive environments. It is commonly used in applications such as tank linings, sewerage systems and coastal engineering projects. The aim is to protect the concrete from chemical attack in the presence of aggressive substances, such as those found in road salts, acids and sea spray. In order to achieve the desired properties, corrosion-resistant concrete requires different mixture proportions and advanced methods of application.
The most common way of improving the corrosion resistance of concrete is through the use of the pozzolanic process. Pozzolanas are materials, usually natural, which contain silica or alumina and react with the calcium hydroxide produced in cement hydration to form calcium silicates and calcium aluminates, which are resistant to corrosion. The most common pozzolanas used today are fly ash, crushed brick and lime. Often, these ingredients are combined to create a blend of pozzolanas.
Another effective way to reduce the effects of corrosion is to use a protective coating which can be applied over the concrete surface after it is cured. The coatings mostly used for this purpose are epoxies, bitumens, limestone, silicones and organic resins. These provide an additional layer of protection by reducing water penetration and providing a barrier against the corrosive agents.
The process of creating corrosion-resistant concrete starts with the selection of appropriate materials. The concrete should be designed to have superior properties, such as low permeability and high compressive strength, which will make it less likely to suffer damage due to chemical attack. The quality of the concrete mix and the water-cement ratio should also be closely monitored.
The concrete mix materials used in the production of corrosion-resistant concrete should contain pozzolanas, protective coatings, air entraining agents and corrosion inhibitors. The proportion of pozzolanic material used in the construction should be carefully determined, as it affects the amount and rate at which water penetrates into the concrete. Air entraining agents can also reduce the penetration rate and improve durability. Corrosion inhibitors prevent the corrosion of metal and steel embedded in the concrete and further reduce the rate of ingress of the agents causing corrosion.
In order for the concrete to remain corrosion-resistant for a longer period of time, it should be cured appropriately and undergo regular maintenance. Regular inspections should be carried out to check for signs of distress, damage or deterioration. Durability tests such as compressive strength tests, water immersion tests and carbonation tests should be carried out as well.
Corrosion-resistant concrete has become increasingly popular over the years due to its superior performance in challenging environments. Good quality materials, special techniques and regular maintenance are essential for creating long-lasting and corrosion-resistant concrete structures.
