Bond behavior of CFRP-steel double-lap joints exposed to marine atmosphere and fatigue loading

Qian Qian Yu, Rui Xin Gao, Xiang Lin Gu, Xiao Ling Zhao, Tao Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

54 Citations (Scopus)


External bonding with carbon fiber-reinforced polymer (CFRP) has been considered great potential in fatigue strengthening of defected steel components. Generally, it takes one to two weeks for a structural adhesive to achieve full strength in such a repair scheme. The potential risk of an environmental attack at the curing stage of adhesive has not been well understood. This paper presents an experimental study on the interfacial behavior of CFRP-steel double-lap joints subjected to salt fog spray or high relative humidity (RH) at the curing stage. Afterwards, the specimens were statically loaded to failure or applied by a pre-set number of fatigue cycles followed by a static test. CFRP laminate-patched specimens had the ability to resist six million high-stress range cycles while CFRP sheet-patched specimens only survived two million low-stress range cycles. After environmental exposure and fatigue loading, the bond strength loss ranged from 1% to 11%. Proper silane treatment was promising to maintain both the strength and stiffness of the bonded joints. Exposure to the harsh environment at the curing stage was detrimental to the mechanical properties of the structural adhesive Araldite 420. The unfavorable effects on the elastic modulus and ultimate strain were comparable to that of long-term exposure for well cured structural adhesive.

Original languageEnglish
Pages (from-to)76-85
Number of pages10
JournalEngineering Structures
Publication statusPublished - 15 Nov 2018
Externally publishedYes


  • Bond
  • CFRP
  • Fatigue loading
  • Marine atmosphere
  • Steel

ASJC Scopus subject areas

  • Civil and Structural Engineering


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