An Experimental Study on the Mechanical Properties of Pultruded CFRP Plates at Elevated Temperatures

The use of fibre-reinforced polymer (FRP) composites in civil infrastructure for strengthening and repair applications is becoming more and more widespread. The use of FRP composites for structural members is also gaining popularity. The performance of FRP materials under elevated temperatures is, however, a very real design issue. An accurate understanding of the material properties and behaviour of FRP at such high temperatures are crucial and necessary pieces of information that are surprisingly scarce in the literature. This paper therefore presents the mechanical properties of pultruded carbon fibre-reinforced polymer (CFRP) plates at elevated temperatures. More specifically, CFRP pultruded plate coupons were tested at steady state for temperatures ranging from approximately 20 to 700°C. The tests showed the tensile strength of pultruded CFRP plate to decrease for temperature ranges of 20 to 150°C and 450 to 706°C. Between these temperature ranges, the tensile strength decreased by a small amount while at 300°C the ultimate strength was approximately 50 % of the room temperature strength. At the peak temperature of about 700°C, the tensile strength of the FRP plate was as low as 7 % of the room temperature tensile strength.