A TWENTY-YEAR REPORT ON THE ILLINOIS CONTINUOUSLY REINFORCED PAVEMENT

IN 1947-48 EIGHT EXPERIMENTAL CRCP SECTIONS WITH LENGTHS RANGING FROM 3,500- TO 4,230-FT. WERE CONSTRUCTED ON U.S. 40 IN ILLINOIS. HALF THE SECTIONS WERE 7-IN. UNIFORMLY THICK AND THE OTHERS WERE 8 IN. ALL PLACED DIRECTLY ON A NATURAL PUMPING-SUSCEPTIBLE CLAY SUBGRADE. LONGITUDINAL STEEL PERCENTAGES WERE 0.3, 0.5, 0.7 AND 1.0 OF THE GROSS PAVEMENT CROSS SECTIONS AND WERE COMPOSED OF DEFORMED RAIL STEEL BARS ASSEMBLED ON CHAIRS UTILIZING 30 BAR DIAMETER LAPS. NO 3 BILLET STEEL BARS WERE PLACED ON BOTH 12-IN. AND 18-IN. CENTERS TRANSVERSELY ACROSS THE 22-FT. WIDE PAVEMENTS TO ACT AS TIE BARS AND NO LONGITUDINAL JOINTING WAS USED. AIR ENTRAINED CONCRETE WAS PLACED IN A SINGLE LIFT. THE STEEL IS 3-IN. BELOW THE FINISHED SURFACE. AN ADJACENT SECTION OF 10-IN. REINFORCED CONCRETE WITH 100-FT. JOINT SPACINGS ON GRANULAR SUBBASE WAS USED AS A CONTROL AND ALL PAVEMENT WAS SUBJECTED TO TWO-WAY TRAFFIC. THE PAVEMENT HAS BEEN CAREFULLY OBSERVED OVER THE YEARS AND REPORTED AT THE HRB IN 1947, 1951, AND 1959. THE OBSERVATIONS OF TRANSVERSE CRACK SPACING AND WIDTH, LONGITUDINAL CRACKING, PUMPING, LENGTH CHANGES, STEEL STRESSES, TRAFFIC RIDING QUALITY AND PERFORMANCE SHOW THAT: (1) CRACK FREQUENCY IS PROPORTIONAL TO -- AND CRACK WIDTH IS INVERSELY PROPORTIONAL TO -- THE STEEL PERCENTAGE, (2) CRACK WIDTHS AND SPACINGS CHANGE WITH AGE BUT ONLY SLOWLY AFTER 5 YEARS, (3) NO STRONG DIFFERENCES IN PERFORMANCE EXIST BETWEEN 7- AND 8-IN. PAVEMENTS, (4) UNSIGHTLY LONGITUDINAL CRACKING OCCURRED AND THE TRANSVERSE STEEL WAS INADEQUATE, (5) CONSTRUCTION JOINTS AND TERMINAL JOINTS ARE POTENTIAL TROUBLE SPOTS, (6) PUMPING CAN OCCUR, AND (7) SATISFACTORY PERFORMANCE TO THE SECTIONS WITH 0.3 PERCENT STEEL FOR MUCH LONGER THAN THE 20-YEAR PERIOD IS NOT EXPECTED. OVERALL, THE PROJECT WAS VERY SUCCESSFULL AND HAS YIELDED MUCH INFORMATION TO AID IN THE DESIGN OF OTHER PAVEMENTS OF THIS TYPE. /BPR/

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Filing Info

  • Accession Number: 00206316
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT
  • Created Date: Jan 16 1976 12:00AM