Performance of reactive powder concrete with different fiber varieties at higher temperatures and retention periods

Abstract

Reactive Powder Concrete (RPC) is used to create high-rise buildings, thermal power plants, nuclear power plants, and footbridges worldwide. RPC performance at high temperatures and retention periods must be assessed. In the present study, RPC (110 MPa) samples were prepared with different fiber verities at an optimum fiber dosage of 0.5% by weight of cement. The fibers used in the present study are polypropylene fibers, polyester fibers, and a combination of polypropylene and polyester fibers with 0.5% fiber dosage. The fiber-reinforced RPC was exposed to elevated temperatures ranging from 200°C to 800°C with different retention periods such as 30, 60, 90 and 120 minutes. The evaluation includes determining remaining physical characteristics like color change, fracture formation, weight loss, and residual mechanical strength like reduced compressive strength. Also used for non-destructive testing was ultrasonic pulse velocity. Water absorption of Reactive Powder Concrete (RPC) samples after different exposure durations has been compared to diverse RPC mixes with different fiber kinds. Scanning Electron Microscopes were used to observe microstructure and assess deuteriation of hydrated substances at extreme temperatures with varying retention times. Results demonstrate increased strength for all fiber-reinforced RPC varieties at 200°C for up to 120 minutes. The strength was raised at 400°C for 30 minutes under retention. All retention durations showed a decrease in strength for fiber-reinforced RPC at 600°C and 800°C. RPC with polyester fiber has 10-15% greater residual strength than other fibers during 600-800°C retention durations. Polypropelene fiber reinforced RPC absorbs 6-12% more water than polyester and mixed fibers after 120 minutes at 800°C.