Development of Long Carbon Fiber-Reinforced Concrete for Dynamic Strengthening

This paper discusses the development and testing of long carbon fibers—fibers 75 mm long or longer—to improve the resistance of reinforced concrete to dynamic loading, such as blasts and impact. In the past, attempts to use long fibers in concrete have failed as a result of both balling (agglomeration) and poor dispersion of the fibers. In the present study, two types of long carbon fibers were developed and optimized for their use in reinforced concrete. The resulting long carbon fiber-reinforced concrete (LCFRC) was subsequently evaluated through impact and blast testing. Full-scale blast testing revealed that these fibers significantly increased the resistance of concrete spalling. In terms of the amount of material lost during the blast, LCFRC panels outperformed nonfiber concrete panels by nearly a factor of 10. This significant reduction in weight loss for the LCFRC panels translates into a substantial decrease in harmful, flying debris in a blast event, and a corresponding reduction in blast lethality.