IDENTIFICATION OF FROST-SUSCEPTIBLE PARTICLES IN CONCRETE AGGREGATES

AGGREGATE TEST METHODS TO IDENTIFY FROST-SUSCEPTIBLE PARTICLES IN CONCRETE AGGREGATES ARE EVALUATED. TWO APPROACHES TO THE PROBLEM OF IDENTIFYING FROST-SUSCEPTIBLE AGGREGATE PARTICLES WERE FOLLOWED. RELATIVELY HOMOGENEOUS AGGREGATE FRACTIONS WERE TESTED IN CONCRETE UNDER SIMULATED FIELD CONDITIONS, TO (1) DEVELOP A RATIONAL TEST METHOD INCORPORATING ELEMENTS OF FIELD EXPOSURE CONDITIONS, AND (2) ESTABLISH MEANINGFUL BASES OF AGGREGATE PERFORMANCE AGAINST WHICH OTHER TEST METHODS COULD BE COMPARED. THE SECOND APPROACH EXPLORED THE POTENTIALITIES OF SINGLE AGGREGATE PARTICLE TESTS AS SIMPLE, QUICK, AND ECONOMICAL MEANS OF IDENTIFYING FROST-SUSCEPTIBLE AGGREGATES. THE BASIC MECHANISMS OF FROST ACTION WERE ALSO INVESTIGATED. PETROLOGICAL STUDIES SUBJECTED THE AGGREGATES TO THREE FRACTIONATION PROCESSES TO OBTAIN RELATIVELY UNIFORM TEST FRACTIONS. RESEARCH CONCLUSIONS ARE THAT: (1) A RELIABLE QUANTITATIVE EVALUATION OF AGGREGATE FROST SUSCEPTIBILITY CAN BE ACHIEVED BY THE SLOW-COOLING METHOD, ORIGINALLY PROPOSED BY POWERS AND EXTENSIVELY INVESTIGATED, AND (2) THE MORE ECONOMICAL RAPID TEST METHODS YIELD RELATIVE RATINGS OF AGGREGATES WITH RESPECT TO FROST SUSCEPTIBILITY. THE SINGLE- PARTICLE TEST OF PERMEABILITY AND VOLUME CHANGE DURING COOLING IS THE MOST DISCRIMINATING OF THE RAPID METHODS STUDIED. VACUUM SATURATED ABSORPTION IS ONLY SLIGHTLY INFERIOR AS A BASIS FOR PERFORMANCE RATING. EXCEPT IN EXTREME CASES, RAPID TESTS ARE NOT LIKELY TO PROVIDE A SOUND BASIS FOR ACCEPTING OR CONDEMNING AGGREGATES WITH RESPECT TO THEIR FROST SUSCEPTIBILITY. IT IS RECOMMENDED THAT RESEARCH BE CONDUCTED TO DEVELOP ENVIRONMENTAL EXPOSURE INDICES. REFERENCES: IDENTIFICATION OF CONCRETE AGGREGATES EXHIBITING FROST SUSCEPTIBILITY, T. D. LARSON, A. BOETTCHER, P. D. CADY, M. FRANZEN, J. R. REED, NCHRP REPORT 15, 1965. A CRITICAL REVIEW OF LITERATURE TREATING METHODS OF IDENTIFYING AGGREGATES SUBJECT TO DESTRUCTIVE VOLUME CHANGE WHEN FROZEN IN CONCRETE, AND A PROPOSED PROGRAM OF RESEARCH, T. D. LARSON, P. D. CARY, M. FRANZEN, J. R. REED, HRB SPECIAL REPORT 80, 1964. AGGREGATE, THE DEGREE OF SATURATION AND THE PREVAILING ENVIRONMENTAL CONDITIONS ARE AS IMPORTANT AS THE DELETERIOUS CHARACTERISTICS OF THE AGGREGATE. RAPID TESTS ARE NOT LIKELY TO PROVIDE A SOUND BASIS FOR ACCEPTING OR CONDEMNING AGGREGATES WITH RESPECT TO THEIR FROST SUSCEPTIBILITY. THE QUESTION OF WHETHER THE AGGREGATE WILL PERFORM SATISFACTORILY UNDER SPECIFIED CONDITIONS IN THE FIELD MUST BE ANSWERED BY FIELD EXPERIENCE OR BY A LABORATORY TEST, SUCH AS THE SLOW-COOLING METHOD, THAT CLOSELY ASSIMULATES THE ANTICIPATED CONDITIONS OF FIELD EXPOSURE. PETROLOGICAL FRACTIONATION OF RAW AGGREGATE MATERIALS IS NECESSARY FOR MEANINGFUL EVALUATION OF FROST SUSCEPTIBILITY.

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    • 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. 62 PP, 30 FIG, 44 TAB, 16 REF, 8 APP
  • Authors:
    • Larson, T D
    • Cady, P D
  • Publication Date: 1969

Media Info

  • Media Type: Digital/other
  • Serial:
    • NCHRP Report
    • Issue Number: 66
    • Publisher: Transportation Research Board
    • ISSN: 0077-5614
  • Publication flags:

    Open Access (libre)

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Filing Info

  • Accession Number: 00217794
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Jun 29 1970 12:00AM