Fiber Reinforced Self-Compacting Concrete (FR-SCC): a state of the art perspective

Fiber Reinforced Self-Compacting Concrete (FR-SCC) combines the benefits of highly flowable concrete in the fresh state with the enhanced performance in the hardened state in terms of crack control and fracture toughness provided by the wirelike fiber reinforcement. Thanks to the suitably adapted rheology of the concrete matrix, it is possible to achieve a uniform dispersion of fibers, which is of the foremost importance for a reliable performance of structural elements. Balanced viscosity of concrete may also be helpful to drive the fibers along the concrete flow direction. An ad-hoc designed casting process may hence lead to an orientation of the fibers “tailored” to the intended application, which is along the anticipated directions of the principal tensile stressed within the structural element when in service. This converges towards a “holistic” approach to the design of structure made with highly flowable/self compacting Fiber Reinforced Concrete (FRC), which encompasses the influence of fresh state performance and casting process on fiber dispersion and orientation an the related outcomes in terms of hardened state properties. The influence of the flow-driven fiber dispersion and orientation on the mechanical performance represents a key distinctive feature of self-consolidating FRC as compared to traditional vibrated FRC, which cannot be disregarded when analyzing engineering and mechanical properties of the material. A thorough understanding is required of the mechanisms underlying the connection between mix-design and fresh state performance, on one hand, and the dispersion and orientation of the fibers on the other hand, also in the context with monitoring and prediction to achieve the anticipated performance in the hardened state. In this framework, this paper will provide a review, based on the author’s own research as well as on a broad literature survey, of the aforementioned topics and of their influence on the engineering and mechanical properties of FR-SCC in order to address its use for high end structural applications, among which some distinctive case studies will be also presented.