CHEMICAL ATTACK ON CONCRETE

ACIDS AND CERTAIN SALTS, SUCH AS MAGNESIUM AND AMMONIA SALTS, DISINTEGRATE MACADAM STARTING FROM THE SURFACE. SOFT WATER HAS PRACTICALLY NO AGGRESSIVE ACTION, WHILE ORGANIC FATS AND OILS REDUCE THE STRENGTH OF THE CONCRETE. SULPHATES CAN PENETRATE LESS DENSE MACADAM AND CAUSE EXPANSION THROUGH THE FORMATION OF TRISULPHATE (ETTRINGIT) AND GYPSUM. AS THE DEGREE OF ATTACK BY WATER AND SOILS DEPENDS PRIMARILY ON THE CONCENTRATION OF THE AGGRESSIVE SUBSTANCES, LIMIT VALUES CAN BE QUOTED FROM WHICH THE ACTION CAN BE ASSESSED QUITE SIMPLY. AT HIGH TEMPERATURES AND IN QUICK FLOWING WATER A HIGHER DEGREE OF AGGRESSION CAN BE EXPECTED. A REDUCTION IN THE INTENSITY OF ATTACK CAN BE EXPECTED IN GROUND WATER, AS THE AGGRESSIVE CONSTITUENTS REGENERATE ONLY SLOWLY. THE MAIN DETERMINATIVE FACTOR FOR THE RESISTANCE OF CONCRETE TO CHEMICAL ATTACK IS ITS DENSITY. IN THE CASE OF AGGRESSIVE ACTION BY ACID WATERS AND SOILS THE USE OF LIMESTONE AS AN ADDITIVE IS ONLY ADVANTAGEOUS WHEN THE ACIDS RENEW THEMSELVES VERY SLOWLY. IN GENERAL, INSOLUBLE ROCKS ARE BETTER. IN WATERS HAVING MORE THAN 400 MAGNESIUM SULPHATE CONTENT PER LITRE SULPHATE RESISTANT CEMENTS HAVE PROVED HIGHLY SUCCESSFUL. SEA WATER HAS PRACTICALLY NO ACTION ON CONCRETE, IRRESPECTIVE OF THE TYPE OF CEMENT USED. /RRL/

  • Supplemental Notes:
    • Vol 17, No 2, PP 47-50, 1 FIG, 2 PHOT, 25 REF
  • Authors:
    • Locher, F W
  • Publication Date: 1967-2

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  • Accession Number: 00212844
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Aug 5 1994 12:00AM