APPLICATION OF DEFLECTIONS AND DEFLECTION BASINS TO CONSTRUCTION CONTROL, PAVEMENT DESIGN, AND MAINTENANCE REQUIREMENTS-FINAL REPORT

THERE IS A NEED TO DEFINE NOT ONLY THE MAGNITUDES OF THE DEFLECTION MEASUREMENTS BUT TO USE ALSO THE SHAPE OF THE DEFLECTION BASIN. FOR THIS REASON, THREE PARAMETERS ARE USED TO DESCRIBE THE BASIN CURVE. THEY ARE: DYNAFLECT MAXIMUM DEFLECTION (DMD), THE NUMERICAL VALUE OF THE DYNAFLECTS FIRST SENSOR; SURFACE CURVATURE INDEX (SCR), THE NUMERICAL BETWEEN THE FIRST AND SECOND SENSORS; AND BASE CURVATURE INDEX (BCR), THE NUMERICAL DIFFERENCE BETWEEN THE FOURTH AND FIFTH SENSORS. BY OBSERVING THE DMD, SCI, AND BCI, A TOTAL PICTURE IS AVAILABLE OF THE STRUCTURAL CAPABILITY OF THE MEASURED PAVEMENT STRUCTURE. COMPUTER PROGRAMS UTILIZED THE IBM 360 COMPUTER AND CALCOMP PLOTTER IN THE ANALYSIS OF THE DEFLECTION BASIN SHAPE AS WELL AS IN THE TEMPERATURE AND LAYER EQUIVALENCY STUDIES. IN THE TEMPERATURE STUDY CONDUCTED, IT WAS THE OBJECTIVE TO FIND A TEMPERATURE CORRECTION FACTOR FOR USE IN ELIMINATING TEMPERATURE AS A VARIABLE IN DEFLECTION MEASUREMENTS. LITERATURE WAS REVIEWED AND A DATA COLLECTION PLAN CONCEIVED AND IMPLEMENTED. IT WAS FOUND THAT THE DEFLECTION-TEMPERATURE RELATIONSHIP COULD NOT BE SEPARATED FROM THE MANY OTHER VARIABLES INVOLVED. IT WAS ALSO INDICATED IN THE RESULTS THAT VARIABLES SUCH AS AGE AND SEASONAL VARIATION HAVE LARGE EFFECT ON THE TEMPERATURE-DEFLECTION CURVES. AN OVERLAY DESIGN PROCEDURE WAS ESTABLISHED WHICH USED THE MEASURED DEFLECTION ON A WEAK PAVEMENT AND THE TRAFFIC INFORMATION FOR THAT ROAD SECTION TO FIND THE REQUIRED OVERLAY THICKNESS. THIS THICKNESS COULD ALSO BE CONVERTED TO A REQUIRED STRUCTURAL NUMBER AND THEN BASED ON LAYER EQUIVALENCY: OTHER MATERIALS COULD BE USED TO STRENGTHEN THE ROADWAY. IT WAS FOUND IN REGARD TO EMBANKMENT HEIGHT THAT THERE COULD BE FOUND IN AREAS OF WEAK SUBGRADE A MINIMUM EMBANKMENT FILL WHICH THE PROFILE DESIGNER COULD USE WITHOUT FEAR OF INADEQUATE SUPPORT. THE DYNAFLECT WAS FOUND TO BE INADEQUATE FOR CONSTRUCTION CONTROL. THE FACTORS, RESILIENCE, AGE OF SURFACING, DENSITY, MOISTURE, SOIL SUPPORT, AND VOLUME OF TRAFFIC, WERE TREATED BRIEFLY. RESILIENCE WAS FOUND NOT TO EXHIBIT THE STATE-WIDE VARIATION WHICH WAS ANTICIPATED AT THE TIME OF THE ORIGINAL PROPOSAL. FOR THIS REASON IT WAS NOT GIVEN THE SIGNIFICANCE OF SOME OF THE OTHER FACTORS. AGE OF SURFACE, SOIL SUPPORT, AND VOLUME OF TRAFFIC ARE INCLUDED IN A FIVE YEAR STUDY IN WHICH NO DEFINITE CONCLUSIONS HAVE BEEN REACHED AT PRESENT. DENSITY WAS STUDIED QUALITATIVELY AS WAS MOISTURE. INDICATIONS THAT THESE FACTORS DO AFFECT DEFLECTION MEASUREMENTS ARE PRESENT. HOWEVER, MORE WORK IS NEEDED IN THESE AND OTHER AREAS TO FIND MORE PRACTICAL USES FOR THE DYNAFLECT. /AUTHOR/

• Corporate Authors:

  Utah State Department of Highways

  757 West Second South
  Salt Lake City, UT  United States  84104

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • PETERSON, G
  • Shepard, L W
  • Keane, E G
• Publication Date: 0

Subject/Index Terms

• TRT Terms: Computer programs; Construction management; Deflection; Density; Maintenance; Measurement; Moisture content; Overlays (Pavements); Pavement design; Reviews; Seasons; Sensors; Temperature; Thickness
• Uncontrolled Terms: Seasonal variations
• Old TRIS Terms: Construction control
• Subject Areas: Construction; Highways; Maintenance and Preservation; Pavements;

Filing Info

• Accession Number: 00206454
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: Study No 906
• Files: TRIS, USDOT
• Created Date: Feb 15 1972 12:00AM