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Concrete is the most widely used construction material on the planet and when reinforced with steel, becomes the cheapest and most versatile compositesystem used in any superstructure. The single biggest cause of premature failure in reinforced concrete is the corrosion of steel from chlorides. Repair of thesestructures is steadily increasing, especially in the Pacific Northwest as many structures are at or nearing 40 to 100 years old. During repair, it is commonto protect the corroded reinforcing steel (subsequent to sufficient cleaning) with a coating or another type of corrosion mitigation system.The purpose of this study was to qualitatively and quantitatively compare different types of materials, products and systems of products that are currentlyin commercial production, as well as in the conceptual research and design stage.Reinforcement steel bars were protected with different materials/systems, encased in chloride laden concrete and immersed in salt baths with a smallinduced current to simulate chloride infiltration and accelerate corrosion. Reference bars were left uncoated to compare as some engineers/designers preferno additional corrosion protection system during repairs.The effects of corrosion were documented and compared via electrochemical testing (half-cell measurements), visual examination (steel, coatings, andgalvanic anodes), metallurgical analysis (steel and coatings, reduction in effective diameters and cross-sectional areas), and mechanical testing (tensile andbending).The results were compared and summarized using a weighted rubric with point totals and a ranking system. In addition, the effects of uncoated sectionsdirectly adjacent to coated sections ),which is lacking in research, were quantified and explored. Similarly, samples were also purposefully left uncoated at targeted locations (5% of surface) tosimulate improper application.The results of this study can be directly and immediately applicable to the building science, building envelope consulting and concrete restoration industries.While some specifications and guidelines are available, none provide any real specificity or confidence in corrosion protection a crucial component inreinforced concrete repair. Engineers, designers and asset planners/managers will be able to use these results to assist with any type of reinforced concreterepair (buildings, parking garages, bridges), ultimately creating more durable structures and prolonging service lives.
Citation: Thermal Buildings XIV 2019
Product Details
- Published:
- 2019
- Number of Pages:
- 9
- Units of Measure:
- Dual
- File Size:
- 1 file , 1.7 MB
- Product Code(s):
- D-Bldgs19-086
