Fibre reinforced polymers (FRP) and FRP-concrete composites subjected to various loads and environmental exposures.

摘要

The problems associated with corrosion and deterioration of reinforcing steel have caused attention to be focused on fibre reinforced polymers (FRP) as a potential strengthening material in concrete structures. The effectiveness of FRP structural upgrade has been demonstrated repeatedly in short-term laboratory tests and field applications. However, the data on the durability of FRP subjected to various types of loads and environmental exposure in civil structures is still lacking.; This thesis reports the results of testing 2108 specimens and evaluates the mechanical performance and durability of FRP and FRP-concrete composites for applications in civil structures and nuclear power plants. The mechanical study included testing glass and carbon fabrics, FRP coupons, FRP-FRP single lap bonded specimens, FRP bonded concrete prisms, and FRP wrapped concrete cylinders under static loads. Analytical equations were developed to model the load-deformation response of FRP-FRP bond, FRP-concrete bond, and FRP wrapped concrete cylinders. The time-dependent behaviours for FRP and its bonds under sustained loads and impact loads were also studied. The time-dependent behaviour of FRP coupons and FRP bonded concrete prisms under sustained loads were empirically modeled.; Durability evaluation of materials involved testing the post-exposure performance of the specimens mentioned above subjected to gamma radiation, loss of coolant accident (in a nuclear power plant) condition, sustained and cyclic high temperatures, cyclic low temperature, alkali solutions, water, and outdoor environments. The results of the durability tests showed that FRP materials had good resistance to all of the exposures studied. However, FRP-FRP bonds and FRP-concrete bonds are unable to maintain their load carrying capacity if they are subjected simultaneously to stress and temperatures close to the glass transition temperature of epoxy. It was also observed that moisture had the most deleterious effects on the FRP and its bonds.; The analytical modeling and durability evaluations reported in this thesis were carried out independent of each other. The continuation of this study would be to integrate the analytical equations from the mechanical tests and the results of the durability tests in parametric studies to propose models that would predict the behaviour of FRP reinforced structure under the combined effects of load and exposure.