EFFECT OF MAXIMUM SIZE OF COARSE AGGREGATE ON D-CRACKING IN CONCRETE PAVEMENTS

Field and laboratory observations have indicated that D-cracking is caused by freeze-thaw failures in certain types of coarse aggregate particles. In areas where durable aggregates are not available, it has been found that the rate of development of D-cracking can be reduced by decreasing the maximum particle size. These observations were extended during a laboratory investigation that was carried out to find a test procedure that would distinguish between durable coarse aggregates and those that cause D-cracking and provide an indication of the benefits to be derived by reducing the maximum particle size. Exploratory work indicated that a rapid freeze-thaw procedure similar to ASTM Designation C666-71 would be suitable. A failure criterion of 0.032 to 0.033 percent expansion in 350 or fewer cycles was established on the basis of the service records of 15 sources from which the test materials were obtained. Studies of the effect of maximum particle size on durability indicated that decreasing the size from 1 1/2 in. to 1 in. and 1/2 in. reduced expansions to varying degrees. These findings are in line with the critical size concept for aggregate that was developed in previous work. It is recommended that, where D-cracking is a problem, similar testing programs be set up to evaluate coarse aggregate sources on an individual basis and to determine the benefits to be derived by reducing maximum particle sizes to improve durability. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 33-43
  • Monograph Title: Grading of concrete aggregates
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00159545
  • Record Type: Publication
  • ISBN: 0309021723
  • Files: TRIS, TRB
  • Created Date: Sep 20 1977 12:00AM