Durable and highly dissipative fibrous composites for strengthening coastal military constructions

Reinforced concrete strategic structures for military purposes are often established in coastal or offshore areas, widely subjected to chemical attacks, mainly due to an aggressive saline and acid environments. Porosity of cementitious conglomerates favour penetration of chlorides, which tend to corrode the internal metallic rebar. The reinforcement of structures with fibrous composite materials is a viable solution to restore the initial requirements of the building, especially when it exerts defence purposes. Among synthetic fibres, polyphenylenebenzobisoxazole (PBO) is an organic fibre based on linked aromatic structures with high elastic modulus and tensile strength and highly dissipative attitudes. In this work, the assessment of durability of continuous fibre-reinforced cementitious mortar (FRCM) composites is carried out comparing the mechanical performance of laminates subjected to uni-axial tensile tests. It is found that PBO-FRCM presents high resistance against aggressive environments and specifically preserve its mechanical strength in the presence of salt-water, where other reinforcing materials undergo a dramatic degradation process.