REACTIVITY OF ROCKS /IN RUSSIAN/

THE REACTIVITY OF 15 ROCK VARIETIES IS INVESTIGATED. REACTIVITY IMPLIES THE CORROSION OF AGGREGATES FROM THESE ROCKS BY CEMENT ALKALIES. IT WAS DETERMINED BY: (1) ANALYSIS OF THE MINERALOGICAL-PETROGRAPHICAL COMPOSITION OF THE ROCKS, (2) CHEMICAL (AMOUNT OF DISSOLVED SILICA), AND (3) EXAMINING CORROSION OF THE AGGREGATE GRAINS. REACTIVITY ESTIMATIONS ACCORDING TO (1) WERE COMPARED WITH DATA OBTAINED BY METHOD (2) UNDER PREDETERMINED CONDITIONS. THOSE ARE BASED ON THE RATIO OF DISSOLVED SILICA (S MILLIMOLES/1.) TO REDUCTION OF ALKYL IN THE SOLUTION (R MILLIMOLES/1.). BOTH METHODS YIELDED ANALOGOUS RESULTS. EIGHT ROCK SAMPLES (QUARTZ, SANDSTONE, ANDESITE, QUARTZ-CHALCEDONE FLINT, PERLITE, GRAVEL, TUFF, SAND, GRAVEL) WITH S/R IS GREATER THAN 1 AND DISSOLVED SILICA IS GREATER THAN 50 MILLIMOLES/1. ARE REACTIVE. SEVEN SAMPLES (PORPHURITE, WELDED TUFF, GRANITE, SEMIMINERAL SANDSTONE, CRYSTAL, SHALES. TRACHITE-LIPARITE, DOLOMITE) SHOWED S/R IS LESS THAN 1, DISSOLVED SILICA IS LESS THAN 50 MILLIMOLES/1. AND ARE NONREACTIVE. CORROSION TRAILS ARE PERFORMED, BY KEEPING THE AGGREGATES, CONTAINING VARIOUS AMOUNTS OF CEMENT, UNDER OBSERVATION FOR 1 YEAR. CORROSION ON THE AGGREGATE GRAINS IS CHECKED PERIODICALLY BY MICROSCOPE AND ELECTRON MICROSCOPE. NEARLY ALL THE SAMPLES REPORTED TO BE REACTIVE TO (1) AND (2) DISPLAYED SIGNS OF CORROSION AFTER ASYMPTOTICALLY EQUAL TO 180 DAYS (AT AN ALKALI CONTENT OF 0.84%). ALL SAMPLES ARE CORRODED AFTER 1 YEAR. THE NONREACTIVE SAMPLES DID NOT INDICATE ANY CORROSION. A CERTAIN DISCREPANCY BETWEEN THE RESULTS OF (3) AND THOSE OF (1) AND (2) IN THE CASE OF TUFF IS EXPLAINED BY THE GREATER PORSITY OF THE MATERIAL, LEADING TO FASTER CORROSION. SEDIMENTARY ROCKS USED FOR THE PRODUCTION OF CRUSHED STONE ARE REACTIVE IN THE PRESENCE OF OPAL AND CHALCEDONE. AMONG THE IGNEOUS ROCKS THE TUFFS OF GRANITE ROCKS AND DIRITES, CONTAINING VOLCANIC GLASSES, ARE REACTIVE. IT IS RECOMMENDED TO GIVE THE CHEMICAL METHOD OFFICIAL RECONGITION, LIMITING THE APPLICATION OF AGGREGATES FOR CONCRETE IN ACCORDANCE WITH SILICA. THE METHOD ALLOWS THE FORECAST OF POTENTIAL CORROSION; HOWEVER, THE DETERMINATION OF A POSSIBLE DILATION OF THE CONCRETE OWING TO THE VARIOUS AGGREGATES WOULD REQUIRE A SEPARATE INVESTIGATION IN EACH INSTANCE. /LCPC/A/RRL/

  • Supplemental Notes:
    • No 22, pp 78-88
  • Corporate Authors:

    Inst Nerud Stroit Mater Gidromekh /Ussr

    ,    
  • Authors:
    • Kadantseva, K I
    • Malyshev, N I
    • Tokarev, P Y
  • Publication Date: 1967

Subject/Index Terms

Filing Info

  • Accession Number: 00237587
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Nov 9 1970 12:00AM