PREMATURE CRACKING OF CONCRETE BRIDGE DECKS: CAUSES AND METHODS OF PREVENTION

Newly constructed bridge decks were examined in order to identify the factors that cause cracking and ways in which the cracking might be reduced. The research included field surveys that showed transverse cracking to be the prevalent type associated with new bridges. Factors potentially influencing transverse cracking were studied and compared with the design and construction practice of the Pennsylvania Department of Transportation. Preliminary findings indicated that the main cause of transverse cracking is the shrinkage of hardened concrete. Further study and tests provided conclusive evidence of thermal shrinkage and drying shrinkage. Correlation of the cracking performance of several newly constructed decks with the shrinkage actually measured in the deck concrete showed that transverse cracking occurred where the shrinkage measurements were high. The findings further indicated that the type of aggregate used in the mix was a major factor associated with shrinkage cracking. Thermal shrinkage is affected by the amount of temperature change during the curing period as well as the coefficient of thermal expansion of concrete, which is mainly aggregate-related. It was noted that thermal shrinkage and cracking were especially severe in concretes that were subjected to large temperature changes associated with cold-weather curing. The research recommends the maximum acceptable shrinkage, implementation of a shrinkage verification test for use in approving mix designs, and temperature control during cold-weather curing.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 163-175
  • Monograph Title: FOURTH INTERNATIONAL BRIDGE ENGINEERING CONFERENCE, SAN FRANCISCO, CALIFORNIA, AUGUST 28-30, 1995. CONFERENCE PROCEEDINGS, 2 VOLUMES
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00711685
  • Record Type: Publication
  • ISBN: 0309061091
  • Files: TRIS, TRB
  • Created Date: Sep 5 1995 12:00AM