Behavior of foamed concrete reinforced with hybrid fibers and exposed to elevated temperatures

This paper demonstrates the behavior of foamed concrete reinforced with either or both carbon fibers and polypropylene fibers exposed to elevated temperatures. Various volumetric fractions of carbon fibers (0.5, 1 and 1.5%) were used to reinforce foamed concrete mix. Also, hybrid fibers of carbon fibers (CF) and polypropylene fibers (PPF) as 1%CF + 0.5% PPF and 0.5%CF + 1%PPF were prepared. Lastly, the mono polypropylene fibers as 1.5% PPF were used to reinforce the foamed concrete mix. These different mixes were tested, compressive strength, splitting tensile strength, flexural strength and flexural toughness tests. Besides, the heating procedure of the specimens was done by applying them to different burning degrees, which were 200, 250, 300, 350 and 400 °C. The results illustrated that the compressive and flexural tensile strengths of lightweight foamed concrete (LWFC) decreased with the increasing temperature. However, the highest effects on these strengths appeared once the temperature raised to 400 °C. The LWFC mix reinforced with polypropylene fiber exhibits more sensitive to elevated temperature than LWFC mixes reinforced with carbon fiber due to low melting point of polypropylene fiber.