ABSTRACT
Hot dip galvanizing of metallic structures is a corrosion protection technique that consists in immersing the metallic piece in a molten zinc bath at 450°C, creating intermetallic bonds between steel and zinc, which promotes both cathodic and barrier protection to steel. The protection of reinforcing steel through hot dip galvanizing has been used for many years in the United States and Europe, mostly in bridges and overpasses. In Brazil, the protection of steel reinforcing bars against corrosion is not a widespread practice. This happens because there is a strong culture of a short-term view concerning the relationship between initial cost and durability of structures.
The additional initial cost in the utilization of hot dip galvanized bars in infrastructure work is approximately 4% of total cost, which is easily offset by considering the gains in durability and reduction in maintenance costs of structures along its lifespan. It is estimated that the first maintenance work in a galvanized rebar structure occurs in not less than 30 years after work conclusion, while a structure with uncoated bars usually demands maintenance work in approximately 10 years. Even though hot dip galvanizing increases lifespan of steel structures, it does not affect its mechanical properties, so it is used in the same conditions of uncoated rebar.
This paper aims to demonstrate the equal performance between hot dip galvanized rebar and uncoated rebar regarding its mechanical properties by showing the results of traction and bending tests in both coated and uncoated rebar of 10 and 25 mm. In addition, it verifies the quality of the coating by showing the results of adherence, thickness and uniformity tests in galvanized bars and promotes the advantages of coated rebar in the increase of steel reinforced structures lifespan.
