The present research work investigates the effect of elevated temperature on the structural behavior of reinforced concrete (RC) beams strengthened with FRP laminates and protected using different external coating layers.. The first phase of this research consisted of testing 81 concrete cubes protected by different coating materials (cement, perlite or vermiculite mortar, Aswan clay, or ceramic fiber blanket) under variable degrees of elevated temperature and for different durations. The second phase consisted of testing 36 beams, strengthened externally by FRP, protected with different coating layers, and subjected to 600oC for two hours duration, left to cool gradually, and then tested till failure.
The obtained experimental results demonstrated the effect of the reduction in flexural capacity of unstrengthens and FRP-strengthened RC beams due to high temperature. All tested beams coating layers showed protection during exposure to 600°C for 2 hours, by reducing heat transfer thus providing higher fire rating and preserving the load carrying capacity. Further enhancement was achieved by using a double layer of ceramic fiber blanket followed by one of the tested materials. Finally, it was concluded that the most efficient protection was achieved by using a double coating system of ceramic fiber and perlite mortar, where the FRP-strengthened beam subjected to 600oC for two hours lost only 5% of the load carrying capacity compared to the control beam which has not been subject to elevated temperature. |
