Relaxation, creep, and fatigue behavior of carbon fiber reinforced plastic tendons

Hamid Saadatmanesh, Fares E. Tannous

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

Corrosion of steel tendons is a major problem in prestressed and posttensioned concrete structures. Fiber reinforced plastics (FRPs) are a promising alternative to steel due to their high tensile strength, light weight, and resistance to electrochemical corrosion. Different types of FRP tendons have been developed to potentially replace steel tendons in areas where corrosion is a problem. However, before field application of FRPs as prestressing elements, their long-term behavior must be investigated. This paper presents relaxation, creep, and tension-tension fatigue test results of two carbon fiber reinforced plastic (CFRP) tendons, namely, Leadline PC-D8 8-mm-(5/16-in.)-diameter, and 1 x 7-7.5-mm-(5/16-in.)-diameter carbon fiber composite cable (CFCC). Twelve Leadline and 12 CFCC tendon specimens were tested in air at temperatures of-30, 25, and 60 C to determine their relaxation behavior. In addition, the relaxation behavior of 24 Lead-line and 24 CFCC samples was examined in chemical solutions simulating aggressive field conditions. The loss of tensile force for the 3000 hr test duration at stress ratios of 0.4 and 0.6 was generally less than 10 percent, and it depended primarily on the initial stress level and the type and temperature of the environment. Preliminary investigation of creep behavior of Leadline and CFCC in air and in chemical solutions was also conducted. Six samples of Leadline and six samples of CFCC were subjected to sustained load at room temperature in air, in alkaline, and in acidic solutions, for a period of 3000 hr. Creep behavior of both tendons was good; however, the creep strains were higher in solutions than in air. Furthermore, 190 samples of Leadline and CFCC were tested in tension-tension fatigue to examine the effect of repeated loading on the modulus of elasticity. Poissons ratio, and the tensile strength of these types of tendons. Fatigue strength was generally good and depended on the stress range and initial stress level.

Original languageEnglish (US)
Pages (from-to)143-153
Number of pages11
JournalACI Materials Journal
Volume96
Issue number2
StatePublished - Mar 1 1999

Keywords

  • Environments
  • Modulus of elasticity
  • Poisson's ratio
  • Prestressing steels
  • Tensile strength

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)

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