Effect of carbon fiber on mechanical properties of reactive powder concrete exposed to elevated temperatures

An ultra-high-performance cement-based composite like reactive powder concrete (RPC) achieves its exceptional engineering properties due to a dense and homogenous microstructure. To improve the ductility and fire-resistance, RPC is of ten reinforced with a high volume of steel fibers (SF). Due to the issues of high density, low durability, and high conductivity; there is a need to study RPC with lightweight and durable fibers. In this research, the mechanical properties of RPC are studied with a single and hybrid fiber mixture of carbon fiber (CF) and conventional SF. The mechanical properties of plain and fiber-reinforced RPC were examined after exposure to 200 degrees C, 400 degrees C, 600 degrees C, and 800 degrees C temperatures for the 2 h. The results showed that CFRPC mechanically performs up to 85-90% potential of conventional SFRPC. Hybridization of 1.5% SF and 0.5% CF produced synergistic effects on the mechanical properties of RPC at both normal and elevated temperatures. After exposure to 800 degrees C, CFRPC showed about 2, 4, and 5 times higher residual compressive, tensile, and flexural strength an plain RPC, respectively. Compressive strength-per-unit weight of CFRPC was notably higher than SFRPC.

Automated summary

The study shows that a hybrid fiber combination of carbon fiber and conventional steel fiber can improve the mechanical properties of RPC, especially under high temperature conditions. CFRPC exhibits higher residual compressive, tensile, and flexural strength at 800 degrees Celsius. Carbon fiber shows significant advantages in compressive strength and strength-per-unit weight of RPC.