Transient Thermal Tensile Behaviour of Novel Pitch-Based Ultra-High Modulus CFRP Tendons

• Published in: Polymers Vol. 8; no. 12; p. 446
• Main Authors: Terrasi, Giovanni Pietro, McIntyre, Emma R E, Bisby, Luke A, Lämmlein, Tobias D, Lura, Pietro
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.12.2016; MDPI
• Subjects: Ambient temperature; Carbon fiber reinforced plastics; carbon fibre reinforced polymers (CFRPs); Coal tar; Concrete construction; Construction industry; Design engineering; Digital imaging; dynamic mechanical thermal analysis (DMTA); Failure; Fiber reinforced polymers; Fire resistance; high elastic modulus; High temperature; high temperature behaviour; Mechanical properties; Pitch (material); Polymers; Prestressing; Strain; Tendons; tensile properties; Tensile strength; Tensile tests; thermogravimetric analysis (TGA); carbon fibre reinforced polymers (CFRPs); tensile properties; thermogravimetric analysis (TGA); dynamic mechanical thermal analysis (DMTA); high temperature behaviour; high elastic modulus
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym8120446

A novel ultra-high modulus carbon fibre reinforced polymer (CFRP) prestressing tendon made from coal tar pitch-based carbon fibres was characterized in terms of high temperature tensile strength (up to 570 °C) with a series of transient thermal and steady state temperature tensile tests. Digital image correlation was used to capture the high temperature strain development during thermal and mechanical loading. Complementary thermogravimetric (TGA) and dynamic mechanical thermal (DMTA) experiments were performed on the tendons to elucidate their high temperature thermal and mechanical behaviour. The novel CFRP tendons investigated in the present study showed an ambient temperature design tensile strength of 1400 MPa. Their failure temperature at a sustained prestress level of 50% of the design tensile strength was 409 °C, which is higher than the failure temperature of most fibre reinforced polymer rebars used in civil engineering applications at similar utilisation levels. This high-temperature tensile strength shows that there is potential to use the novel high modulus CFRP tendons in CFRP pretensioned concrete elements for building applications that fulfill the fire resistance criteria typically applied within the construction industry.