Design of novel glass fiber reinforced polypropylene cable-anchor component and its long-term properties exposed in alkaline solution

The high performance and long life of engineering structures can be realized through replacing traditional steel materials with glass fiber reinforced polypropylene composites with high toughness/durability, flexibility design and recycling. In addition, the anchorage problem of composites needs to be solved by developing new anchorage technologies or forms. In the present paper, a new type cable-anchor component was developed to prolong the service life and realize the reliable anchoring of composite. The influence mechanism of arc angle (10o, 20o, and 30o) on the mechanical properties of cable-anchor component was evaluated through the experimental and mechanical simulation. The durability evolution of cable-anchor component exposed to alkali solution environment was investigated through macro-performance test and microstructure analysis. The results showed the tensile strength retention of cable-anchor component was up to 88.7% at the arc angles of 10o under the circumferential constraint of carbon fiber. Larger arc angle increased the stress concentration and fiber misalignment of transition area between arc and straight segments, leading to the formation and propagation of defects or cracks in transition areas and early fracture failure. The saturated water absorption and diffusion coefficient of glass fiber reinforced polypropylene composites were obtained to be 0.78% and 4.41×10-14 m2/s, respectively. Compared with nylon 6 and epoxy resin, polypropylene has excellent hydrophobic properties with the diffusion coefficient ratio of 0.0077 and 0.024. At the longest immersion, the tensile strength retentions of cable-anchor component were 61.8% and the failure mode changed from component longitudinal splitting to brittleness fracture of arc region. The degradation mechanism was attributed to the initial defects of arc section formed and expanded under the complex stress and corrosive medium, which further aggravated the fiber/resin interfacial debonding. Through comparing with other glass fiber reinforced thermoplastic and thermosetting composites, the cable-anchor component has higher tensile strength retention after the immersion of alkaline solution owing to excellent hydrophobicity behavior of polypropylene and efficient preparation process.