TESTING OF CONCRETE BY ULTRASONIC-PULSE TECHNIQUE

A DESCRIPTION IS GIVEN OF THE APPARATUS FOR MAKING HIGH-PRECISION MEASUREMENTS OF THE VELOCITY OF AN ULTRASONIC PULSE IN CONCRETE. THE USE OF THIS VELOCITY (THE LONGITUDINAL-WAVE VELOCITY) AS A CRITERION OF QUALITY IS DISCUSSED WITH REFERENCE TO SUCH CONVENTIONAL CRITERIA AS THE MODULUS OF RUPTURE, COMPRESSIVE STRENGTH, DENSITY OF THE CONCRETE. THE EFFECT OF A LARGE NUMBER OF VARIABLES HAS BEEN STUDIED, AND IT WAS FOUND THAT THE LONGITUDINAL-WAVE VELOCITY COULD BE USED TO MEASURE CHANGES IN THE QUALITY OF THE CONCRETE, EXCEPT WHEN THE AGGREGATE-TO-CEMENT RATIO WAS VARIED. FOR THIS REASON THE LONGITUDINAL-WAVE VELOCITY CANNOT BE USED AS A GENERAL CRITERION OF CONCRETE QUALITY. THE TECHNIQUE CAN BE APPLIED DIRECTLY TO THE CONCRETE IN STRUCTURAL MEMBERS AND CAN BE USED TO DETECT ANY WEAKNESS DUE TO DETERIORATION OR POOR COMPACTION. WHERE TEST SPECIMENS OF THE STRUCTURAL CONCRETE ARE AVAILABLE, A CALIBRATION CURVE CAN BE OBTAINED FROM WHICH THE EQUIVALENT STRENGTH OF THE CONCRETE CAN BE INFERRED. EXAMPLES OF SUCH TESTS ARE GIVEN. LABORATORY APPLICATIONS OF THE TECHNIQUE HAVE BEEN THE STUDY OF CRACK FORMATION IN CONCRETE (1) UNDER LOAD, (2) SUBJECTED TO FROST ACTION, AND (3) WHEN INVERSION TAKES PLACE IN HIGH-ALUMINA CEMENT. AN INTERESTING RESULT SHOWED THAT CONCRETE CUBES IN COMPRESSION DEVELOP INITIAL CRACKS WITH PLANES PARALLEL TO THE DIRECTION OF APPLICATION OF THE LOAD AT ABOUT 30 PERCENT OF THE ULTIMATE LOAD. /AUTHOR/

  • Supplemental Notes:
    • Vol 32, pp 258-275, 22 FIG, 4 TAB, 3 PHOT, 20 REF
  • Authors:
    • Jones, R
  • Publication Date: 1953

Media Info

  • Monograph Title: Proceedings of the Thirty-Second Annual Meeting of the Highway Research Board, Washington, D.C., January 13-16, 1953
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00213952
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 1971 12:00AM