Fatigue Performance of Ballastless Track Slabs Reinforced with BFRP and SFCB

Abstract

The main objective of this research was to evaluate the behavior of fiber-reinforced polymer (FRP) bar-reinforced ballastless track slab subjected to a fatigue loading. Five ballastless track slabs were experimentally tested, which were reinforced with steel fiber–reinforced polymer composite bars (SFCBs), basalt fiber–reinforced polymer (BFRP) bars, and traditional steel bars, respectively. All slabs were loaded in three-point loading and designed to have the same initial stiffness of cross section. To simulate the wheel cyclic load, different maximum loads were selected, but the minimum load was the same for all slabs. At the same maximum load of 1.76 static wheel loads, the stiffness degradation and crack width in the SFCB slab were similar to those of the traditional RC slab and survived 3,000,000 fatigue cycles, showing good fatigue performance and a residual strength reduction of only approximately 3%. At the maximum load level of 60% of the ultimate load static capacity, both the SFCB slab and RC slab could satisfy the requirements of 2,000,000 fatigue cycles, whereas the stress in SFCB was only approximately 66% of the steel bar, and the crack width in the SFCB slab was 1.15 times greater than that in the RC slab. After 2,000,000 fatigue cycles, the maximum load level was increased to approximately 65% of the ultimate load static capacity. The stiffness of the RC slab decreased by 21% and was close to failure, whereas the SFCB slab only decreased by 6%. Finally, the BFRP slab had the shortest fatigue life (only 1,600,000 cycles) with a maximum load of only 52% of the ultimate load static capacity owing to the possibly reduced bond strength between concrete and BFRPs.