STEEL CORROSION IN CONCRETE -- HOW DOES IT OCCUR?

Abstract

THE TESTS DESCRIBED IN THIS PAPER WERE DESIGNED TO: IDENTIFY THE MECHANISM BY WHICH CORROSION OF STEEL IS INITIATED, PROVIDE QUANITATIVE INFORMATION ABOUT THE EFFECTS OF CHLORIDES, AND DETERMINE IF A PREDICTABLE THRESHOLD OF CORROSION EXISTS. LABORATORY STUDIES ARE REPORTED ON THE CORROSION OF BARE STEEL RODS IN ENVIRONMENTS SIMULATING POROUS CONCRETE CONTAMINATED WITH CHLORIDES. THE INITIATION OF CORROSION IS SHOWN TO REQUIRE FREE OXYGEN AT THE STEEL SURFACE AND A RATIO OF CHLORIDE TO HYDROXYL ION ACTIVITY OF AT LEAST 0.6. A PROBABILITY MODEL IS USED TO EXPLAIN THE CHLORIDE EFFECT AND TO PREDICT THE THRESHOLD VALUE CAUSING CORROSION. /AUTHOR/