RELATIONSHIP OF PHYSICAL PROPERTIES OF SOME IOWA CARBONATE AGGREGATES TO DURABILITY OF CONCRETE

A STUDY OF CARBONATE ROCKS USED FOR CONCRETE AGGREGATE WAS CONDUCTED FOR THE IOWA STATE HIGHWAY COMMISSION TO DETERMINE THE FACTORS IN THE AGGREGATE CAUSING DISTRESS IN CONCRETE AND TO ESTABLISH CRITERIA FOR RECOGNIZING POTENTIALLY POOR AGGREGATES. DEVONIAN ROCKS FROM THE CEDAR VALLEY FORMATION WHICH IS DIVIDED INTO THE SOLON, RAPID AND CORALVILLE MEMBERS WERE SAMPLED ON A BED-BY-BED BASIS IN FOUR QUARRIES, ONE OF WHICH IS THE CONDEMNED GLORY QUARRY. THE GLORY AGGREGATE WAS PRODUCED FROM THE RAPID MEMBER, WHICH SERVES AS A STANDARD OF COMPARISON. THE AGGREGATES WERE INVESTIGATED BY PETROGRAPHIC EXAMINATION TO DETERMINE INSOLUBLE RESIDUE, CLAY MINERALS PRESENT, POROSITY, PORE SIZE AND PORE SIZE DISTRIBUTION DATA. A PETROGRAPHIC STUDY WAS ALSO MADE OF DISTRESSED CONCRETE CONTAINING GLORY AGGREGATE. THE RESULTS WERE CORRELATED WITH FREEZE-THAW DATA AND SERVICE RECORDS. A PETROGRAPHIC STUDY OF THE ROCKS FROM THE CEDAR VALLEY FORMATION INDICATES THAT THE RAPID MEMBER HAS A DISTINCTIVE LITHOLOGY WHICH IS EASILY RECOGNIZED. ROCKS WITH SUCH A LITHOLOGY HAVE POOR FREEZE-THAW RESISTANCE. THE INSOLUBLE RESIDUE CONTENT OF SUCH ROCKS IS CONSIDERED AN INDICATION OF DURABILITY. ROCKS FROM THIS FORMATION WITH HIGH RESIDUE SHOW POOR FREEZE-THAW RESISTANCE AND ROCKS WITH LOW RESIDUE SHOW GOOD FREEZE-THAW RESITANCE AND MAKE SERVICEABLE CONCRETE. THE RAPID MEMBER IS CHARACTERISTICALLY HIGH IN RESIDUE. POROSITY DATA ARE ON THE WHOLE VARIABLE AND INCONCLUSIVE, BUT SOME CORRELATION TO FREEZE-THAW DATA IS EVIDENT IN ROCKS OF UNIFORM LITHOLOGY. THE ONLY CLAY MINERAL PRESENT IS ILLITE WHICH IS RESTRICTED ALMOST ENTIRELY TO BEDS OF RAPID LITHOLOGY. ROCKS FROM THE CONCRETE AGGREGATE LEDGES ARE ALMOST DEVOID OF CLAY. PORE SIZE DISTRIBUTION DATA AND EFFECTIVE POROSITY ARE RELATED TO THE LITHOLOGY OF THE ROCKS AND TO FREEZE-THAW RESULTS. PORE SIZE DISTRIBUTION DATA FOR THE RAPID ARE DISTINCTIVE AND SHOW THAT MOST OF THE PORES ARE UNIFOMLY SMALL AND AVERAGE 0.1 MICRON IN RADIUS. THE RAPID AGGREGATE HAS HIGHER CAPILLARY PRESSURES AND MORE PORE AREA AVAILABLE FOR REACTION. PETROGRAPHIC INVESTIGATION OF DISTRESSED CONCRETE MADE FROM GLORY AGGREGATE SHOWED THE PRESENCE OF REACTION RIMS AROUND PIECES OF ROCK OF RAPID LITHOLOGY. IT IS CONCLUDED THAT IMPURE CARBONATE ROCKS FROM THE CEDAR VALLEY FORMATION CHARACTERIZED BY HIGH RESIDUE AND CLAY CONTENT ARE DELETERIOUS. PURE ROCK TYPES OF HIGH CARBONATE CONTENT, LOW RESIDUE AND LITTLE IF ANY CLAY HAVE A GOOD SERVICE RECORD. BECAUSE OF HIGHER CAPILLARY PRESSURE, THE RAPID AGGREGATE WOULD RETAIN FLUID MORE EASILY AND PROVIDE MORE PORE SURFACE AREA FOR CHEMICAL ACTIVITY. A STUDY OF REACTION RIMS IN RAPID AGGREGATE IN DISTRESSED CONCRETE INDICATES THAT A REACTION HAS OCCURRED WITH THE CEMENT. THE REACTION PROBABLY CAUSES A GRADUAL WEAKENING OF THE CONCRETE WHICH CONDITIONS IT TO LATER FAILURE BY FREEZING OR EXTERNAL STRESSES. /AUTHOR/

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  • Supplemental Notes:
    • No 196, pp 1-16, 11 FIG, 4 TAB, 17 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
  • Authors:
    • Lemish, John
    • Rush, F Eugene
    • Hiltrop, Carl L
  • Publication Date: 1958

Media Info

  • Media Type: Digital/other
  • Pagination: 16p
  • Monograph Title: Air voids in concrete and characteristics of aggregates
  • Serial:

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Filing Info

  • Accession Number: 00213247
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 12 1994 12:00AM