Fibre reinforced polymer (FRP) bars are increasingly being used as replacement of steel reinforcing bars in the design and construction of concrete buildings. However, the deterioration of mechanical properties of FRP materials on heating is, in general, not well known and has not been well characterized for the wide variety of FRP materials currently available; this hinders application of FRP materials in many cases. To better understand the complexities of FRP bars’ response at high temperature, an experimental study into the tensile mechanical response of FRP reinforcing bars at high temperature is presented. The results of dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) tests are used to evaluate the glass transition temperature (Tg) and decomposition processes (Td) of a specific commercially available glass FRP (GFRP) reinforcing bar for concrete reinforcement. Results are presented from direct tensile tests on the FRP bars at different steady-state temperatures varying from 20°C to temperatures at which crystallization of the resin occurs (i.e. 500°C). These are compared against results from the small-scale characterization tests and semi-empricial models available in the literature. Finally, a novel model for the reduction in tensile strength of FRP materials at high temperature, which requires only small scale DMA and DSC testing, along with a small number of tension tests at elevated temperature, is proposed.
|Title of host publication||8th International Conference on Structures in Fire|
|Place of Publication||Shanghai|
|Publisher||Tongji University Press|
|Publication status||Published - 1 Jun 2014|