Behaviour of CFRC beams strengthened by FFRP laminates under static and impact loadings

This paper investigates the impact resistance of a new construction material, being coconut fibre reinforced concrete (CFRC) beams strengthened with flax fibre reinforced polymer (FFRP) laminates. To study the impact resistance of the material, a series of CFRC specimens with various FFRP thicknesses (2-, 4- and 6-layer) were experimentally studied through static and drop weight impact tests. Parameters of the FFRP-CFRC beams, i.e. the impact force, deflection, energy absorption, dynamic increase factor (DIF) and damage pattern were studied. In addition, the influence of the FFRP laminate thickness was investigated in terms of (1) flexural strength and toughness under static loading, (2) flexural behaviour under impact loading, and (3) failure mode. The results showed that FFRP laminates were effective in enhancing the flexural strength under both static and impact loadings. It is also suggested that FFRP-CFRC composites could be used as environmentally-friendly materials for protective structures in resisting impact loadings.