Recent Developments in Corrosion Protection of Steel Structures

Abstract

Corrosion of structural steel is cited as one of the reasons for not preferring steel intensive construction in India, though the same is widely used in the advanced countries. The present paper is devoted to understanding the mechanism of corrosion with reference to use of structural steel and the methods available for corrosion protection. Protection of steel can be done by envisaging proper detailing at the design stage itself as also by use of high performance paint/coating systems. Thermal metal spray coating involving use of liquid aluminum can give a maintenance free life of around 50 years without painting during this period. High build epoxy, chlorinated rubber, modified alkyd micacious iron oxide kind of paint systems can give paint life of 12-25 years depending upon actual formulation and the aggressiveness of the environment. Surface preparation is also extremely important. Steel-concrete composite construction is cost effective technology, which marries the advantages of both steel and concrete. While exposed steel beams and columns can be effectively protected against corrosion by application of paints and coatings, corrosion of reinforcing bars in the concrete slab has been an area of concern. Effective measures of coating the bars with epoxy or other suitable coatings or use of corrosion resistant TMT bars can prov-ide an effective solution. It has been concluded that corrosion is not a problem in steel intensive construction today and available know-ledge with national laboratories, corrosion experts, acad-emics and paint companies should be used to adopt cost effective design and surface protection systems.