THE PROTECTION OF FRESH ROAD CONCRETE AGAINST THE EFFECT OF THAWING SALT

WALL CONSTITUTED AND HARDENED ROAD CONCRETE WHICH HAS A MINIMUM AIR CONTENT OF 3.5% PRODUCED BY AIR ENTRAINING CONCRETE AGGREGATES /AIR ENTRAINED CONCRETE/ IS ADEQUATELY RESISTANT TO THAWING SALT UNDER THE CLIMATIC CONDITIONS PREVAILING HERE, AS TESTS AND EXPERIENCE SHOW. IF REGULAR AIR ENTRAINED CONCRETE WHICH HAS BEEN PRODUCED AND STORED IN LATE AUTUMN AT LOW TEMPERATURES AND DAMP WEATHER IS SHORTLY AFTERWARDS EXPOSED TO A HEAVY STRESS OF FROST/THAWING SALT THEN, DESPITE THE AIR ENTRAINING CONTENT, DAMAGE IN THE FIRST WINTER IS CONSIDERED POSSIBLE THROUGH PARTIAL WEATHERING OF THE SURFACE. THROUGH THE PRESENT LABORATORY TESTS THE INTENTION WAS TO DETERMINE WHETHER SUCH DAMAGE COULD OCCUR AND, AS THE CASE MAY BE, JUST WHAT MEASURES ARE NECESSARY IN ORDER TO PROTECT SUCH YOUNG AIR ENTRAINED CONCRETE AGAINST WEATHERING. FOR THIS PURPOSE NUMEROUS SLABS OF GOOD ROAD CONCRETE HAVING AN AIR CONTENT USUALLY OF ABOUT 3.5% WERE SUBJECTED TO 90 SHARP FROST/THAWING SALT ALTERNATIONS AT THE AGE OF 42 DAYS AFTER DAMP PRESTORAGE AT PLUS 5 DEGREES C. IN SOME CASES THE UPPER SURFACES OF THE SLABS RECEIVED AN IMPREGNATION WITH LINSEED OIL, EPOXIDE RESIN SOLUTION, ANTHRACENE OIL OR SILICON BEFORE THE CHANGES. SLABS OF THE COMPARISON CONCRETE, STORED AT PLUS 20 DEGREES C AND WITHOUT ARTIFICIAL AIR PORES AND WITHOUT IMPREGNATION /COMPRESSIVE STRENGTH 587/KP/SQ CM AT THE BEGINNING OF THE CHANGE AT AN AGE OF 42 DAYS/ SHOWED HEAVY DAMAGE AND WEATHERED AWAY TO A DEPTH OF 1 CM /3/8 IN/ AFTER THE FROST/THAWING SALT ALTERNATIONS, HERE, COARSE PARTICLES OF AGGREGATE ALSO BECAME DETACHED. ON THE OTHERWISE EQUAL, LIKEWISE NON-IMPREGNATED AIR ENTRAINED CONCRETE, HARDENED AT PLUS 5 DEGREES AND HAVING APPROX. 3.5% AIR CONTENT /COMPRESSIVE STRENGTH 445 KP/SQ CM AT THE BEGINNING OF THE CHANGES AT AN AGE OF 42 DAYS/, EVEN UNDER THESE UNFAVOURABLE CONDITIONS MERELY A MAXIMUM 1 MM /1/25 IN/ THICKNESS OF FINE MORTAR LAYER WEATHERED AWAY. THE TOP SURFACE OF SLABS OF AIR ENTRAINED CONCRETE, UPON WHICH A COMMERCIAL AFTER-TREATMENT FILM WAS SPRAYED A FEW HOURS AFTER PRODUCTION, SHOWED ABOUT THE SAME LOW DEGREE OF WEATHERING AS THE ABOVE-MENTIONED SLABS WITH 3.5% AIR CONTENT. SLABS WHICH WERE IMPREGNATED WITH ANTHRACENE OIL OR SILICON SOLUTIONS, OR TO WHICH A SILICON ADDITIVE WAS ADDED TO THE CONCRETE MIXTURE, BEHAVED SIMILARLY. IN THE CASE OF THE SLABS OF AIR ENTRAINED CONCRETE IMPREGNATED WITH LINSEED OIL ONLY THE CEMENT SKIN WEATHERED AWAY, AND THOSE IMPREGNATED WITH EPOXIDE RESIN SOLUTION REMAINED UNCHANGED.

  • Supplemental Notes:
    • Vol15, No4, PP155-159, 3FIG, 4TAB, 25REF
  • Authors:
    • Walz, K
    • Helms-derfert, H
  • Publication Date: 1965-4

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  • Accession Number: 00212251
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Jun 10 1994 12:00AM