Asphalt corrosion-resistant materials
Asphalt and asphalt-based materials are extensively used in a number of civil engineering projects. As such, many of these materials undergo various forms of environmental and physical wear and tear, which may lead to corrosion of the material and cause it to eventually wear out and fail. Asphalt as a material is often selected in cases where an extended period of time and/or extreme environmental conditions will occur. In order to increase the longevity of asphalt pavement and reduce the cost of street maintenance, it is essential to select asphalt corrosion-resistant materials which have the highest resistance to corrosion and wear and tear.
Asphalt-based materials are composed of a combination of mineral materials such as gravel, sand, and other substances. Depending on the materials used and the grade of the asphalt mix, the resistance to corrosion and wear may vary significantly. As asphalt mixes must meet certain criteria to be considered corrosion-resistant, it is important to select asphalt mixes which combine the optimal mineral composition and other additives.
At a minimum, asphalt mixes must contain enough limestone to form an alkali-resistant material. Additionally, asphalt mixes require an appropriate aggregate fraction that is a combination of no more than three types of aggregate. Generally, this fraction should contain a smaller amount of larger sized particles and higher amounts of smaller particles. These particles help to reduce the permeability of the asphalt mix and make it more resistant to corrosive effects.
In addition to the mineral components, other compounds may be added in order to increase the corrosion resistance of asphalt-based materials. For example, additives such as rubber, hydrocarbon wax, and other substances may all be added to the asphalt mix in order to reduce and stabilize water absorption in the material. By controlling the water absorption, asphalt-based materials are more resistant to surface erosion, which can cause significant corrosion in the material.
In rainy, cold climates, it is necessary to use corrosion-resistant asphalt coatings and sealers to maintain the integral strength and properties of the asphalt material. Various asphalt coatings and sealers are available for use, and these should be used according to their specifications. Generally, these coatings and sealers should be applied in two to three coats each. The first coat should be a penetrating coat that adheres to the aggregate surface; the second coat should be a waterproofing coat, and the third coat should be a sacrificial coating that provides protection from the elements.
For extreme climates, asphalt mixes should contain special asphalt resins and modified polymers that are designed to form a protective shield on the material. These polymers will help to reduce water absorption and increase the overall durability of the material.
In order to extend the longevity of asphalt-related materials, asphalt pavements and roofs should be inspected regularly and sealants should be reapplied on a regular basis. Early detection and repair of asphalt-related damages can help to save significant costs and effort in the long run.
