Novel hybrid composites based on glass and sisal fiber for retrofitting of reinforced concrete structures

In this work an attempt has been made to assess the efficacy of hybrid composite system as a potential choice for the retrofitting of reinforced concrete structures. The combination of synthetic and natural fibers are used for the external confinement of concrete cylinders. A comparative performance analysis of hybrid sisal-glass fiber reinforced polymer (HSGFRP) confinement vis a vis carbon fiber reinforced polymer (CFRP), glass fiber reinforced polymer (GFRP) and sisal reinforced polymer (SFRP) individual confinement is carried out. The axial compressive behaviour, stress-strain response and energy absorption characteristics are studied. The inclusion of sisal fibers along with glass fiber is found to improve the energy absorption characteristics. For predicting the ultimate strength of HSGFRP confined concrete, a new equation was developed based on the lateral confining pressure which shows good agreement with the experimental results. Durability performance studies indicated that exposure to wet/dry conditions and temperature variations resulted an increase in strength for all FRP confined specimens and whereas it decreased for unconfined ones.