METHOD OF ESTIMATING CORROSION OF HIGHWAY CULVERTS BY MEANS OF POLARIZATION CURVES

THE INTRODUCTION OF NEW MATERIALS FOR CORRUGATED METAL CULVERTS INITIATED EFFORTS TO DEVELOP A COMPARATIVE CORROSION TEST. THE WORK OF WILLIAM SCHWERDTFEGER AT THE U.S. BUREAU OF STANDARDS PROVED THE USEFULNESS OF POLARIZATION CURVES FOR DETERMINING THE CORROSION OF BURIED METAL. THE APPLICATION OF THE SCHWERDTFEGER METHOD TO FULL- SIZE METAL CULVERT INSTALLED UNDER HIGHWAYS IS DESCRIBED. THE PREFERRED METHOD OF OBTAINING CURVES IS TO USE FOUR AUXILIARY ELECTRODES SYMETRICALLY PLACED NEAR THE ENDS OF THE CULVERT AND TWO REFERENCE ELECTRODES PLACED OVER THE CENTERLINE OF THE CULVERT NEAR THE EDGE OF THE ROADWAY. THE METHOD IS SIMPLE AND INEXPENSIVE AND YIELDS CURVES THAT ARE EASILY INTERPRETED.