The use of protective coatings is to enhance the durability of concrete structures by creating a barrier that will limit the penetration of water, acids, chemicals, solvents, and chlorides that will breakdown industrial or municipal infrastructure. Corrosion in concrete is not just caused by the constituents of wastewater, it can also be caused by the cleaning procedures of water treatment or membrane bioreactor (MBR) systems. Lining solution technologies presented included systems comprised of 100% solids epoxies, epoxy laminate alternatives and elastomer polyurethane applications.
The purpose of this paper is to provide an understanding of two lining solutions: elastomer polyurethane and epoxy laminate systems. The paper will provide insight into the effects of corrosion on concrete infrastructures, identify the various lining solutions, compare, and contrast the application techniques, cost structure, product performance in these environments and highlight project impacts of these solutions that should be considered by specifiers and clients when selecting the lining system for their projects.
Asset owners spend significant monies each year on the construction of new and the maintenance of existing infrastructure. More than ever, these funds can be difficult to procure and budget. The owners include, both municipal and industrial entities and funds are limited in most cases, therefore, asset service life is very important to all parties.
The definition of Concrete Corrosion, "Concrete corrosion is the chemical, colloidal or physicochemical deterioration and disintegration of solid concrete components and structures, due to attack by reactive liquids and gases."1 Furthermore, the corrosion of the steel reinforcement, within the concrete, must also be considered.
Chemical causes of concrete corrosion include.
• Moisture Penetration
• Microbiological induced concrete corrosion from bacteria in wastewater (MIC)
• Carbonation (CO2)
• Sulfide Attacks (H2S)
• Industrial corrosive gases
Often, steel reinforcement (rebar) is corroded by electrochemical reaction. When the rebar corrodes, the resulting rust occupies a greater volume than the steel. This expansion creates tensile stresses in the concrete, which can eventually cause cracking, delamination, and spalling.