Flexural fatigue behavior of reinforced concrete T-beams strengthened with a composite of prestressed steel wire ropes embedded in polyurethane cement (PSWR-PUC)

ABSTRACT

To study the fatigue properties of reinforced concrete (RC) T-beams strengthened with a composite of prestressed steel wire ropes embedded in polyurethane cement (PSWR-PUC), which is an innovative reinforcement method, two RC beams without strengthening, three RC beams with a composite of prestressed steel wire ropes embedded in polymer mortar (PSWR-PM) and three RC beams with PSWR-PUC were designed. Some key parameters, such as the material into which the wire rope is imbedded, the fatigue loading, and the tension of steel wire ropes, are discussed. The experimental results show that PSWR-PUC reinforcement can significantly improve the monotonicity and fatigue performance of RC T-beams. The PSWR-PUC strengthening can significantly reduce beam deflection and steel bar stress. Under the same load, the maximum strain and strain range of PSWR-PUC reinforced beams are significantly smaller than those of PSWR-PM reinforced beams. Due to the excellent properties of polyurethane cement composite with high strength, high bond, and high toughness, the cracking and peeling phenomenon of polymer mortar in PSWR-PUC reinforced beams did not occur, which can improve the fatigue life of beams by reducing the stress of steel bars. Due to the cracking, falling off, and peeling of polymer mortar, the bonded prestressed wire rope becomes unbonded pre-stressed wire rope, which redistributes the stress of the beam and further increases the stress of the steel bars.

Keywords:
Reinforced concrete (RC) T-beams; Bending fatigue; Polyurethane cement (PUC); PSWR-PUC strengthening technique; Prestressed steel wire rope (PSWR)