LONG-TERM TESTS ON THE ACTION OF CHLORIDE ON THE CORROSION OF PRESTRESSING STEELS IN CONCRETE

LANGZEIT-VERSUCHE UEBER DIE WIRKUNG VON CHLORID AUF DIE KORROSION VON SPANNSTAEHLEN IN BETON

A STUDY IS TO BE MADE OF THE ACTION OF CHLORIDE ON STEEL IN CONCRETE, TAKING ACCOUNT OF ALL OTHER POSSIBLE INFLUENCES, SINCE PRESTRESSED STEELS ARE NOT ONLY ENDANGERED BY PITTING, BUT ALSO EXPERIENCE ADDITIONAL DAMAGE AS A RESULT OF EMBRITTLEMENT, STRESS CRACKING CORROSION AND SIMILAR ATTACK. THE FOLLOWING QUESTIONS SHOULD BE ANSWERED BY THE PROGRAMME OF TESTS: 1 - WHAT IS THE EFFECT OF THE LEVEL OF CHLORIDE CONTENT, GIVEN OTHERWISE EQUAL CONDITIONS, ON THE TYPE AND RATE OF CORROSION OF PRESTRESSING STEELS? 2 - HOW QUICKLY DOES THIS CORROSION PROGRESS UNDER VARIOUS ENVIRONMENTAL CONDITIONS? 3 - WHAT EFFECT HAS HEAT TREATMENT DURING THE MANUFACTURE OF CONCRETE ON CORROSION CAUSED BY CHLORIDE? 4 - WHAT IS THE EFFECT OF TYPE OF CEMENT (FOR EXAMPLE PORTLAND CEMENT, PORTLAND CEMENT LOW IN C(3)A ON CHLORIDE CORROSION? 5 - HOW IS THE CORROSION IN CARBONATED CONCRETE AFFECTED BY CHLORIDE? 6 - HOW QUICKLY CAN CHLORIDE DIFFUSE FROM ONE STRUCTURAL PART (SCREED) INTO ANOTHER? SYSTEMATIC STUDIES CAN RESULT IN THE DISCOVERY OF METHODS OF PREVENTION EVEN BEFORE THE PROGRESS OF CORROSION IS FULLY UNDERSTOOD, SO THAT DAMAGE WHICH MIGHT OTHERWISE OCCUR CAN BE PREVENTED IN THE INTERESTS OF PUBLIC SAFETY.