Development of novel CFRP rope structures for reinforcement and prestressing applications – Part A

Carbon-fiber-reinforced polymer (CFRP) reinforcements offer high potential for resource-efficient and durable concrete structures due to their superior tensile properties and corrosion resistance. However, existing CFRP tendons and rope systems are limited in terms of bond performance, anchorage efficiency, bending capability, and applicability to filigree and modular concrete structures. This paper presents the development of novel CFRP rope structures based on preconsolidated, partially profiled carbon rovings combined with thermoplastic and elastomeric impregnation systems. The proposed rope concept features a spiral configuration of seven rovings, consisting of one central unprofiled strand and six surrounding profiled strands to enhance bond behavior. A laboratory-scale rotational manufacturing process is introduced, allowing controlled variation of spiral geometry and structural fixation. In addition, modified tensile testing and load introduction concepts based on segmented grouting were developed to enable reliable characterization of CFRP rope structures with increased diameters up to failure. Experimental investigations focus on tensile and bending behavior relevant to reinforcement and prestressing applications. The novel CFRP ropes achieve Young’s moduli between approximately 140 and 180 GPa and tensile strengths of about 2,350 MPa, exceeding a commercial epoxy-based reference by 10–30 %. Bending tests demonstrate that soft polymer-based impregnation enables small bending radii suitable for coiling and continuous production, while stiffer matrices provide higher axial stiffness at reduced flexibility. Overall, the results highlight the potential of thermoplastic-based CFRP rope systems for material efficient prestressing systems in combination with shaping, modular construction, demountability, recyclability, and future integration of sensor functionalities.