SERVICE TESTING OF BITUMINOUS COATINGS

THE BASIS FOR EVALUATING PROTECTIVE COATINGS REST HEAVILY ON THE PROPERTIES WHICH THE COATINGS EXHIBIT. A BRIEF REVIEW IS PRESENTED OF SOME OF THE PARTICULAR REQUIREMENTS AND MORE IMPORTANT CHARACTERISTIC PROPERTIES WHICH COATINGS MUST HAVE FOR EXPOSURE TO GENERAL CLASSES OF ENVIRONMENT. SERVICE TESTING IS NOT THE ONLY ALL-INCLUSIVE WAY TO EVALUATE THE MERITS AND LIMITATIONS OF PROTECTIVE COATINGS. PRELIMINARY SCREENING TESTS USING PANELS OR TEST COUPONS ARE MOST USEFUL IN ELIMINATING TOTALLY INEFFECTIVE MATERIALS FROM CONSIDERATION ON A SPECIFIC APPLICATION. SERVICE TESTS GENERALLY FALL INTO THE TWO FOLLOWING CATEGORIES: DIRECT TESTS WHICH MAY BE CONDUCTED WHERE IT IS POSSIBLE TO EXAMINE PHYSICALLY THE COATING SYSTEM UNDER ACTUAL CONDITIONS OF EXPOSURE, AND THAT CONDUCTED USING INDIRECT METHODS TO REACH CONCLUSIONS ON COATING EFFECTIVENESS. WHILE THE MAJORITY OF MEASUREMENTS EMPLOYED FOR THE INDIRECT EVALUATION OF COATINGS ARE ELECTRICAL, ONE SPECIFIC TEST INVOLVES A PHYSICAL TYPE OF MEASUREMENT. THIS IS THE EVALUATION OF WATER-LINE FRICTION COEFFICIENTS BY THE HAZEN AND WILLIAMS FORMULA. BECAUSE THE PRIMARY PURPOSE OF PROTECTIVE COATINGS IS TO CONTROL CORROSION, ONE METHOD OF EVALUATION IS TO DETERMINE THE RATE OF CORROSION ON A GIVEN STRUCTURE COATED ACCORDING TO A SET OF SPECIFICATIONS. POLARIZATION MEASUREMENTS ARE ONE APPROACH TO DETERMINING SUCH RATES OF CORROSION ON BURIED STRUCTURES. A MODIFICATION OF CORROSION RATE DATA FOR EVALUATION OF COATING CONDITION WOULD BE THE USE OF MINIMUM CURRENT REQUIRED FOR CATHODIC PROTECTION ON A GIVEN SYSTEM. CATHODIC PROTECTION REQUIRES THAT A STRUCTURE BE POLARIZED TO A PREDETERMINED LEVEL. THE AMOUNT OF CURRENT REQUIRED TO MAINTAIN THIS POLARIZATION OVER A PERIOD OF TIME CAN BE USED AS AN INDEX TO THE CONTINUED EFFECTIVENESS OF THE COATING.

• Supplemental Notes:
  • Vol 58, No 6, PP 70-75, 6 FIG, 11 REF
• Authors:
  • WAGNER, J
• Publication Date: 1966-6

Media Info

• Serial:
  • Industrial & Engineering Chemistry

Subject/Index Terms

• TRT Terms: Bituminous materials; Cathodic protection; Coefficient of friction; Electrical measurement; Evaluation; Level of service; Polarization; Protective coatings; Screenings; Testing
• Uncontrolled Terms: Service
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00211536
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 26 1970 12:00AM