Flexural behaviour of FFRP wrapped CFRC beams under static and impact loadings

The flexural behaviour of a new construction material, flax fibre reinforced polymer (FFRP) wrapped coconut fibre reinforced concrete (CFRC) beams, under static and impact loads was investigated for the first time. Coconut fibre was mixed into concrete and the concrete beams were wrapped externally with flax fibre reinforced polymer (FFRP) laminates. Then static tests, followed by single and repeated impact tests were performed. Three different fibre contents, i.e. 1%, 3% and 5% of cement mass, corresponding to fibre volumes of respectively 0.4%, 1.2% and 2%, were considered. The effect of the coconut fibre content on the dynamic flexural load, deflection, energy absorption and dynamic increase factor (DIF) were analysed to discover the composites impact properties. The test results indicated that the flexural strength of the FFRP-CFRC beams was almost three times higher than that of CFRC beams. Dynamic increase factors (DIFs) of the FFRP-CFRC beams were found not very sensitive to the coconut fibre content but influenced by strain rate. The beams with 3% coconut fibre content were the best in resisting impact when compared with that of FFRP-CFRC beams with 1% and 5% coconut fibre content.