CONCRETE PAVEMENT THICKNESS MEASURED BY TWO METHODS

ON TWO PAVING PROJECTS, SLAB THICKNESS WAS MEASURED AT 25 TEST LOCATIONS BY CORING AND BY A SINGLE MANUFACTURER'S ULTRASONIC METHOD, AND THE RESULTS WERE COMPARED FOR PRECISION. FIRST, THE DIFFERENCE BETWEEN THE THICKNESS CALCULATED FROM ULTRASONIC READINGS AND THAT MEASURED FROM THE CORE WAS DETERMINED AND COMPARED FOR EACH TEST LOCATION. THEN, ALL MEASUREMENTS OBTAINED BY EACH METHOD WERE GROUPED AND COMPARED FOR EACH PROJECT. THE FIRST COMPARISON SHOWED THAT DIFFERENCES CAN BE LARGE AND MAY OCCUR OFTEN, BUT NOTHING COULD BE CONCLUDED ABOUT RELATIVE PRECISION. COMPARING THE GROUPED DATA PROVED MORE MEANINGFUL, AND INFERENCES CONCERNING PRECISION COULD BE DRAWN. THE SONIC THICKNESS FOR EACH LOCATION REPRESENTS THE AVERAGE THICKNESS OF AN AREA OF ABOUT 2-FT DIAMETER. THE CORE REPRESENTS THE AVERAGE THICKNESS OF A MUCH SMALLER 4 IN DIAMETER AREA. THUS, CORE LENGTHS SHOULD INCLUDE MORE EXTREME VALUES, AND THEIR STANDARD DEVIATIONS SHOULD BE LARGER IF THE TWO METHOD ARE EQUALLY PRECISE. SINCE THE STANDARD DEVIATIONS OF SONIC THICKNESSES WERE EQUAL TO OR GREATER THAN THOSE OF CORRESPONDING GROUPS OF CORES, IT IS CONCLUDED THAT SONIC MEASUREMENTS ARE LESS PRECISE THAN CORING. THE COSTS OF MEASURING WITH THE TWO METHODS WERE ALSO COMPARED, AND CORING WAS FOUND TO BE LESS EXPENSIVE, AS WELL AS TO REQUIRE ONLY ONE MAN WHERE THE SONIC METHOD REQUIRES TWO. /AUTHOR/

• Corporate Authors:

  New York State Department of Transportation

  1220 Washington Avenue
  Albany, NY  United States  12232

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Di Cocco, J B
  • Nuzzo, W W
• Publication Date: 0

Subject/Index Terms

• TRT Terms: Core samples; Pavements; Slabs; Thickness; Ultrasonic tests
• Old TRIS Terms: Coring
• Subject Areas: Construction; Geotechnology; Highways; Materials; Pavements;

Filing Info

• Accession Number: 00215939
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: 45-1
• Files: TRIS, USDOT, STATEDOT
• Created Date: Jan 11 1971 12:00AM