Most of the existing engineering structures were built in the last century and have been in service for decades. However, environmental degradation may lead to a reduction in structural performance and service life. The mechanical property data of full-scale structures, such as bridges, are essential for structural health monitoring. For this purpose, five (half) reinforced concrete (RC) T-beams were removed from a retired 31-year-old bridge and subjected to destructive testing. Two loading points were employed, and the flexural and shear capacities of the retired T-beams were studied. The results showed that all the retired beams held high load capacities (exceeding 1400 kN). The two flexural test beams exhibited a high ductility, and the three shear test beams all failed. In addition, the existing cracks in the flexural test beams reopened when the load exceeded 200 kN, while it was 300 kN for the shear test beams. The load-carrying capacity experimental values of the test beams were compared with the ones calculated according to Chinese code JTG-3362-2018; it was shown that the retired T-beams still maintained a high degree of safety margins despite initial defects. The experimental results are expected to provide a reference for the assessment of in-service RC bridges.

High-strength steel-fiber-reinforced concrete (HSFRC) has become increasingly popular as a cast-in-place jointing material in precast concrete bridges and buildings due to its excellent tensile strength and crack resistance. However, working conditions such as emergency repairs and low-temperature constructions require higher demands on the workability and mechanical properties of HSFRC. To this end, a novel rapid-hardening HSFRC has been proposed, which is produced using sulphoaluminate cement (SC) instead of ordinary Portland cement. In this study, quasi-static and dynamic tests were carried out to compare the compressive behavior of conventional and rapid-hardening HSFRCs. The key test variables included SC replacement ratios, concrete curing ages, and strain rates. Test results showed: (1) Rapid-hardening HSFRC exhibited high early strengths of up to 33.14 and 44.9 MPa at the curing age of 4 h, respectively, but its compressive strength and elastic modulus were generally inferior to those of conventional HSFRC. (2) The strain rate sensitivity of rapid-hardening HSFRC was more significant compared to its conventional counterpart and increased with increasing curing ages and strain rates. This study highlights the great potential of rapid-hardening HSFRC in rapid bridge construction.