Rapid Heating of Textile Reinforced Concrete: Effect of Textile Coating and Hybrid Textile Layups

The behavior of Textile Reinforced Concrete (TRC) under increased temperatures has been poorly investigated so far and has been a topic of increasing interest in the past decade. The lack of knowledge is even greater when it comes to the behavior of hybrid reinforcement layups, in which different fiber textiles are combined, and the effect of their coating. This paper focuses on the residual tensile behavior of TRC exposed to high temperatures with high heating rates (that correspond to a fire scenario). The investigated parameters are the fiber material (carbon fibers or glass plus carbon fibers) and the textile finishing (coated or uncoated). The specimens (thin tension coupons) were exposed to fire from both sides. Two fire tests were conducted following a standard fire curve (ISO 834) for 7 and 19 min and the reached temperatures at the coupons were approximately 200 ℃ and 300 ℃, respectively, uniform through the coupons’ thickness. The tensile test results that were conducted on the fire exposed coupons, indicated that the temperature effect on the hybrid layup TRCs is relatively small since the tensile strength and the post-cracking stiffness of the material are mainly controlled by the stronger and stiffer carbon fibers, which are unaffected by these temperatures. Additionally, for temperatures of this level, the effect of the coating seems to be limited, since the residual strength of the specimens with coated textiles was almost unaffected. The post cracking stiffness was either unaffected or even increased, depending on the textile finishing.