Sustainability and renewability in constructional materials and also utilization of such materials for various engineering purpose is
the need of the hour. Green retrofitting with the aid of green fibre reinforced polymer (FRP) materials, made up of natural bio fibres
like sisal would contribute to sustainable development. Non fossil-fuel carbon precursor organic fibres, i.e. sisal FRP composites
were used for retrofitting of reinforced concrete (RC) beams, designed to undergo shear failure. Study in this field aimed at
understanding the effect of natural sisal FRP retrofitting scheme over carbon FRP and glass FRP retrofitting schemes. Two
wrapping configurations i.e. full wrapping and strip wrapping technique both in U-shaped wrap configurations, were used here for
evaluating the shear strengthening effect. The effectiveness of the retrofitting scheme using natural sisal FRP was compared to that
of carbon FRP and glass FRP in terms of ultimate shear strengths, load-deflection behavioural curves and obtained failure modes
of the tested reinforced concrete beams. Failure mode study of retrofitted RC beams displayed promising performance by sisal FRP
similar to that of carbon FRP and glass FRP. Also sisal FRP promoted ductile failure of beams with sufficient warnings and huge
deflections unlike carbon FRP, which underwent sudden FRP rupture and Glass FRP, which underwent sudden debonding. Test
results of this research indicate that lower embodied energy, renewable, sustainable, environment friendly and green materials like
natural sisal fibre FRP, can be effectively utilized for reinforced concrete strengthening in contrast to other artificial FRP products
such as carbon FRP or glass FRP.