Characterization of the Static, Creep, and Fatigue Tensile Behavior of Basalt Fiber/Polypropylene Composite Rods for Passive Concrete Reinforcement

Fiber reinforced polymer (FRP) composites are becoming more frequently adopted as so-called “corrosion-resistant” concrete reinforcement materials, due to their excellent mechanical properties and formability. However, their long-term reliability must be thoroughly investigated in order to understand the failure mechanisms and develop service life models. This study is on the me-chanical properties of a prototype basalt fiber reinforced polypropylene (BFPP) rod under qua-si-static and sustained loading. Static strength and modulus at elevated temperatures do not de-crease significantly, but the variability in strength increases with temperature, as shown by Weibull analysis. Creep behavior is typical of unidirectional FRP, where the creep rupture strength follows a power law. Fatigue at various stress ratios R reveals the sensitivity of composite strength to the matrix damage, which increases at lower values of R (i.e., higher stress amplitudes). These results are discussed in the context of service life and concrete structure design guidelines.