CONTROL OF CRACKING IN PORTLAND CONCRETE PAVEMENT

THE VOLUME CHANGE OF PORTLAND CEMENT CONCRETE DURING HARDENING AND AFTERWARDS DUE TO TEMPERATURE AND MOISTURE CHANGES CONTRIBUTE TO THE FORMATION OF TRANSVERSE CRACKS IN CONCRETE PAVEMENTS. RESTRAINED CURLING OF PAVEMENTS AND WHEEL LOADS ALSO CONTRIBUTE TO DEVELOPMENT OF CRACKS. TRANSVERSE CRACKS ARE A MAJOR PROBLEM WHICH HAS OCCUPIED THE ATTENTION OF HIGHWAY ENGINEERS, DESIGNERS AND MANUFACTURERS FOR THE LAST 50 YEARS. MOST OF THE EFFORTS TO CONTROL CRACKING HAVE INVOLVED THE USE OF TRANSVERSE JOINTS AND/OR REINFORCEMENT AND SUCH FEATURES AS LOAD TRANSFER AND SUBBASES. A VARIETY OF JOINTING PRACTICES HAVE BEEN USED. AN EARLY JOINTING PRACTICE WAS THE USE OF EXPANSION JOINTS AT 800 TO 1000 FT INTERVALS TO ELIMINATE OR MINIMIZE THE OCCURRENCE OF BLOWUPS. THE PRACTICE DID NOT FULFILL ITS OBJECTIVE AND WAS DISCONTINUED IN FAVOR OF EXPANSION JOINTS AT INTERVALS OF 90 TO 120 FT WITH INTERMEDIATE CONTRACTION JOINTS 20 TO 30 FT APART. LATER, BASED ON EXPERIENCE FROM EXPERIMENTAL PAVEMENTS SPONSORED IN 1940, BY THE BUREAU OF PUBLIC ROADS AND THE PORTLAND CEMENT ASSOCIATION, THE PRACTICE OF USING CONTRACTION JOINTS WAS WIDELY ACCEPTED. IN 1960, 25 STATES SPECIFIED SLAB LENGTHS VARYING FROM 15 TO 30 FT, WITH THE PREDOMINATE PRACTICE BEING IN THE 15 TO 20 FT. MORE RECENTLY, THE TREND HAS BEEN TOWARD REINFORCED PAVEMENT WITH JOINT SPACING RANGING FROM 40 TO 100 FEET. DISTRIBUTED REINFORCEMENT DOES NOT PREVENT CRACKS, ITS PURPOSE IS TO HOLD TIGHTLY CLOSED THOSE CRACKS THAT DO OCCUR. THE ANSWER IS CONTINUOUSLY REINFORCED PAVEMENT. TRANSVERSE CRACKS IN CONTINUOUSLY REINFORCED PAVEMENT OCCUR RANDOMLY AT AN EARLY AGE AND ULTIMATELY THE AVERAGE SPACING MAY RANGE FROM 2 TO 10 FEET. THE CRACKS ARE HELD TIGHTLY CLOSED BY THE CONTINUOUS REINFORCEMENTS SO THAT AGGREGATE INTERLOCK REMAINS EFFECTIVE, LOAD TRANSFER AND STRESS REDUCING PROPERTIES ARE RETAINED AT A HIGH LEVEL AND THE STRUCTURAL INTEGRITY OF THE PAVEMENT IS MAINTAINED. WHILE THE FIRST COST OF CONTINUOUSLY REINFORCED PAVEMENT IS SOMEWHAT HIGHER THAN THAT OF CONVENTIONAL PAVEMENT, THE PERFORMANCE OF CONTINUOUSLY REINFORCED PAVEMENTS 14 TO 28 YR OLD INDICATE THAT THE DIFFERENTIAL MAY BE MORE THAN OFFSET BY SAVINGS IN SURFACE MAINTENANCE AND IN A LONGER SERVICE LIFE, SO THAT IN THE LONG RUN CONTINUOUSLY REINFORCED PAVEMENT IS THE BETTER INVESTMENT. THE LOWER MAINTENACE REQUIREMENTS OF CONTINUOUSLY REINFORCED PAVEMENT GIVE IT AN IMPORTANT ADVANTAGE OVER OTHER TYPES.

  • Corporate Authors:

    American Concrete Institute

    38800 Country Club Drive
    Farmington Hills, MI  USA  48331
  • Authors:
    • Lindsay, J D
  • Publication Date: 1968

Subject/Index Terms

Filing Info

  • Accession Number: 00205828
  • Record Type: Publication
  • Source Agency: Am Concrete Inst Journal & Proceedings
  • Report/Paper Numbers: Title No Sp 20-9
  • Files: TRIS
  • Created Date: Sep 28 1970 12:00AM