00213261

Component

http://onlinepubs.trb.org.../hrbbulletin/70/70-001.pdf

A METHOD WAS DEVELOPED WHICH MAKES IT POSSIBLE TO DETERMINE THE CHARACTERISTICS OF THE ENTRAINED AIR VOIDS IN CONCRETE. BRIEFLY, THE PROCEDURE CONSISTED OF CUTTING AND POLISHING A SECTION OF CONCRETE TO EXPOSE THE DISTRIBUTED VOIDS. THE VOIDS THUS EXPOSED WERE THEN FILLED WITH A FLUORESCENT MATERIAL AND PHOTOGRAPHED UNDER ULTRAVIOLET LIGHT. AFTER DETERMINING THE SIZE DISTRIBUTION AND NUMBER OF VOIDS APPEARING ON A PHOTOGRAPH, EQUATIONS DERIVED BY USING THE METHODS OF MATHEMATICAL STATISTICS WERE APPLIED TO DETERMINE THE TRUE PROPERTIES OF THE DISTRIBUTED VOIDS. APPLICATION OF THE METHOD MADE IT POSSIBLE TO COMPARE THE VOID PROPERTIES IN DIFFERENT TYPES OF CONCRETE CONTAINING VARIOUS PERCENTAGES OF ENTRAINED AIR. THE EFFECTS OF THE TWO MOST WIDELY USED AIR-ENTRAINING AGENTS, DAREX AND VINSOL RESIN, WERE ALSO COMPARED. INFORMATION OBTAINED FROM THE TESTS INDICATES THAT THE AVERAGE DIAMETER OF THE VOIDS IN CONCRETE MAY VARY FROM ABOUT 0.1 MM. IN NORMAL CONCRETE TO LESS THAN HALF THAT SIZE IN AIR-ENTRAINED CONCRETE. THE NUMBER OF VOIDS PER UNIT VOLUME OF CONCRETE INCREASED GREATLY WITH A SMALL ADDITION OF ENTRAINED AIR, AND FOR A GIVEN AMOUNT OF ENTRAINED AIR, CONCRETE WITH A HIGH CEMENT CONTENT CONTAINED MORE VOIDS PER UNIT VOLUME THAN CONCRETE WITH A LOW CEMENT CONTENT. DAREX AND VINSOL RESIN PRODUCED ENTRAINED VOIDS WHICH HAD ALMOST IDENTICAL CHARACTERISTICS. /AUTHOR/

No 70, pp 1-10, 7 FIG, 2 TAB, 3 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

01410484

1953

Highway Research Board Bulletin

Air entraining agents; Air voids; Cement content; Concrete tests; Entrained air; Fluorescence; Mathematical analysis; Photographs; Size; Statistical analysis; Test procedures; Ultraviolet radiation; Void ratios

Data and Information Technology; Highways; Materials

TRIS, TRB

Apr 28 1994 12:00AM

• RECORD OF EXPERIMENTAL AIR-ENTRAINED CONCRETE 10 TO 14 YEARS AFTER CONSTRUCTION