STRESS-INDUCED THERMAL AND SHRINKAGE STRAINS IN CONCRETE

A previous material model for the increase of creep of concrete caused by simultaneous drying is extended to describe the effect of both drying and wetting, as well as the increase of creep caused by temperature changes, both heating and cooling. By theoretical arguments and comparisons with numerous existing test data, it is shown that the creep increase due to temperature changes, sometimes called the transitional thermal creep, is physically the same phenomenon as the increse of creep due to humidity changes, known as the Pickett effect (or the drying creep effect). In accord with the previous model for drying creep alone, the present extended model explains the increase of creep due to humidity or temperature changes as a consequence of principally two effects: (1) Stress-induced shrinkage (or swelling) or stress-induced thermal expansion (or contraction); and (2) the distributed tensile cracking (or strain softening) of concrete. The former effect is explained by the previously advanced hypothesis that the creep viscosity depends on the pore humidity rate. The latter effect reduces measured overall deformations, and thus results in the true thermal expansion or shrinkage of uncracked material being considerably larger than observed on load-free companion specimens when significant nonuniformly distrubuted self-equilibrated stresses are produced by the temperature or humidity change. The proposed material model is suitable for finite-element programs.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/07339399
• Corporate Authors:

  American Society of Civil Engineers

  345 East 47th Street
  New York, NY  United States  10017-2398
• Authors:
  • Bazani, Z P
  • Chern, J C
• Publication Date: 1987-10

Media Info

• Features: Appendices; Figures; References;
• Pagination: p. 1493-11
• Serial:
  • Journal of Engineering Mechanics
  • Volume: 113
  • Issue Number: 10
  • Publisher: American Society of Civil Engineers
  • ISSN: 0733-9399
  • EISSN: 1943-7889
  • Serial URL: http://ascelibrary.org/journal/jenmdt

Subject/Index Terms

• TRT Terms: Concrete; Cracking; Creep; Drying; Mathematical models; Shrinkage; Strain (Mechanics); Stresses; Temperature; Thermal stresses
• Uncontrolled Terms: Concrete cracking; Models; Thermal response
• Old TRIS Terms: Concrete creep; Strains
• Subject Areas: Bridges and other structures; Highways; Materials; I20: Design and Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00474791
• Record Type: Publication
• Files: TRIS
• Created Date: Oct 31 1987 12:00AM