Flexural behaviour of glass fibre reinforced polymer (GFRP) bars subjected to elevated temperature

Flexural behaviour of glass fibre reinforced polymer (GFRP) bars subjected to elevated temperature

The FRP reinforced concrete structures may be exposed to high temperatures that may reduce the structural integrity of the bars, and eventually of the entire structure. Therefore, the thermal stability of the FRP bars must be thoroughly investigated before they can be fully utilized in the construction industry. The flexural strength testing has long been a staple technique for measuring the uniaxial tensile strength of the brittle materials because it is inexpensive and convenient to run rather than the direct tension test. Although the results obtained were not the absolute tensile data, they can provide an indication about the relative tensile performance of the FRP bars. In this study, the flexural behaviour of the GFRP bars of varying nominal diameters (12.7 mm, 14.0 mm, 15.9 mm, 17.0 mm, and 20.5 mm) subjected to elevated temperatures (up to 150 °C) was investigated. The results showed that as the temperature increases, the flexural strength and stiffness of the GFRP bars decreases. As the temperature approaches the glass transition temperature (Tg) of the bars, a drastic strength and stiffness reduction was observed. These findings were also observed in the pure tension testing of the FRP bars done by other researchers. The bars with a larger nominal diameter showed a better flexural strength decay resistance than those with a smaller nominal diameter at elevated temperatures. However, a comparable flexural stiffness deterioration was observed at an increasing temperature.

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