Civil Engineering Departmental Seminar - Next-generation reinforced concrete: Brittle behaviour and Fracture Mechanics assessment

Next-generation reinforced concrete: Brittle behaviour and Fracture Mechanics assessment

The present seminar intends to outline the most recent advancements on high-performance concrete structures, with particular focus on the complex phenomena characterising the failure mechanisms of fibre-reinforced, hybrid-reinforced, and FRP-bar reinforced concrete structures. These next-generation brittle-matrix composites can represent an effective solution to the main drawbacks related to conventional reinforced concrete in terms of durability and structural performances.

With regard to fibre-reinforced and hybrid-reinforced concrete structures, by means of the Updated Bridged Crack Model (UBCM) we can address the lack of knowledge about their bearing capacity, which is mainly influenced by fibre volume fraction and bar-reinforcement percentage coupled with their characteristic structural size. This dominant scale effect appears to be crucial to thoroughly understand fibre-reinforced or hybrid-reinforced concrete structural behaviour under flexural loading or low-cycle fatigue.

Furthermore, a correct understanding of the structural effects due to reinforcement, slenderness, and scale in the design of FRP-bar RC structures can lead to an effective development of innovative standard guidelines. In this context, the transition between tensile cracking and compression crushing failures occurring in FRP-bar RC beams is described by means of the Cohesive/Overlapping Crack Model (COCM). Finally, it is highlighted how the structural ductility, which is represented by the plastic rotation capacity of the composite beam, only occurs for high-strength concrete matrix and when the internal reinforcement can slip.