00213401

Monograph

http://onlinepubs.trb.org...ubs/nchrp/nchrp_rpt_65.pdf

INVESTIGATION WAS CONDUCTED TO DEVELOP A SIMPLE AND FAST TEST THAT COULD BE USED TO IDENTIFY AGGREGATES THAT CAUSE POOR CONCRETE PERFORMANCE WHEN FROZEN. A ONE-CYCLE SLOW- FREEZE TEST WAS DEVELOPED AND EVALUATED BY CORRELATING RESULTS WITH THE DURABILITY FACTOR OBTAINED FROM ASTM METHOD C290 (THE STANDARD FREEZING AND THAWING TEST IN WATER). THE ONE-CYCLE TEST INVOLVES FABRICATION OF 3 X16-INCH CONCRETE SPECIMENS USING AGGREGATES REPRESENTATIVE OF THE AGGREGATE SOURCE AND, AFTER 7-DAY CURING, PLACING THE SPECIMENS IN A CONVENTIONAL HOUSEHOLD DEEP FREEZE CHAMBER. STRAIN MEASUREMENTS ARE MADE WITH A WHITTEMORE STRAIN GAUGE AT 5- TO 15-MINUTE INTERVALS OVER A 4-HOUR COOLING PERIOD. FROM THE DATA COLLECTED, THE CUMULATIVE LENGTH CHANGE IS PLOTTED VS. TIME AND THE TIME SLOPE DETERMINED AS THE MINIMUM SLOPE THAT CAN BE FOUND WITHIN A 1/3-HOUR OR GREATER TIME RANGE. NINETEEN COARSE AGGREGATES FROM DIFFERENT PARTS OF THE COUNTRY AND REPRESENTING VARYING PERFORMANCE HISTORIES WERE USED TO FABIRCATE 336 SPECIMENS DURING THE EVALUATION PROGRAM. A SUFFICIENTLY STRONG RELATIONSHIP WAS FOUND BETWEEN THE TIME SLOPE AND THE DURABILITY FACTOR AT 100 FREEZE-THAW CYCLES TO INDICATE THAT THE ONE-CYCLE TEST COULD BE USED AS A SCREENING TEST WHERE THE DURABILITY FACTOR CAN BE CONSIDERED AS A MEASURE OF POTENTIAL FIELD PERFORMANCE. THE METHOD HAS THE ADVANTAGES OF SIMPLICITY, MINIMAL EQUIPMENT REQUIREMENTS, AND RELATIVE RAPIDITY. THE SIGNIFICANCE OF DURABILITY FACTOR IN RELATION TO FIELD PERFORMANCE MUST BE DETERMINED FOR A SPECIFIC AGGREGATE USE AND GEOGRAPHIC LOCATION. THE TEST METHOD AND TESTING PROCEDURES ARE PRESENTED IN DETAIL.

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. No 65, 21 PP, 11 FIG, 20 TAB, 13 REF, 3 APP

1969

NCHRP Report

Digital/other

Alternatives analysis; Coarse aggregates; Concrete; Concrete aggregates; Concrete tests; Durability; Freeze thaw tests; Freezing; Length; Performance; Screenings; Strain measurement; Test procedures; Time

Geotechnology; Highways; Materials

TRIS

Oct 21 1994 12:00AM