Compressive and Bond Behavior of Concrete-Filled Pultruded GFRP and PE Tubes Under Elevated Temperatures

Tabatabaeian Nimavard, Mojtaba | 2023

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 55792 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Khaloo, Alireza
  7. Abstract:
  8. Concrete-filled GFRP and PE tubes are composite systems using the polymeric tubes as confinement for the marine structures to extend their service life. However, elevated temperatures and thermal cycles in marine environments can affect the behavior of such composite systems. In this investigation, the effect of elevated temperatures and thermal cycles on the performance of concrete-filled pultruded GFRP tubes (CFPGT) and concrete-filled polyethylene tubes (CFPT) is assessed, respectively. For this, different parameters such as concrete core strength (30 and 60 MPa), exposure temperature (25, 100, 200, 300, and 400°C), time exposure (60 and 120 min.), number of thermal cycles (50, 100, and 150 cycles), and type of the thermal cycle (Type A and B) are considered to evaluate the compressive and bond behavior of concrete-filled tubes. Mechanical properties of concrete core, hollow and concrete-filled tubes are obtained via compressive and disk-split tests. Also, the push-out test is used to determine the bond strength of specimens. Concerning CFPGTs, the results showed that the maximum load-bearing capacity of the exposed specimens at temperatures of 100, 200, 300, and 400°C was 8%, 22%, 34%, and 51% lower than that of the unexposed specimen, respectively. Regardless of exposure conditions and the concrete core strength, the pultruded GFRP tubes resisted about one fourth of the total load-bearing capacity. Regarding CFPTs, it was shown that the concrete core strength increment can lead to increase in the maximum compressive capacity, while exposing specimens to the thermal cycles reduced both the maximum compressive capacity and ductility. It was also concluded that the exposure temperature and number of thermal cycles increment led to the interlocking and coefficient of kinetic friction increase, resulting higher bond strength. Finally, models are presented to estimate the compressive and bond strength of CFPGTs and CFPTs after exposure
  9. Keywords:
  10. Thermal Cycle ; Compression Strength ; Glass Fiber Reinfoced Polymer (GFRP) ; High Temperature ; Elevated Temperature ; Concrete-Filled Polyethylene Tubes (CFPT) ; Bond Model ; Bond Strength ; Compressive Behavior

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