Jute–Basalt Hybrid Fibre Wrapping for Seismic Retrofitting of Concrete Columns: A Critical Review with a Preliminary Cube Test

Published tests show that a hybrid wrap of two jute and two basalt layers raised cylinder strength by 63.64 percent and energy absorption by 287 percent, kept a confinement effectiveness of 163 to 213 percent after 120 days of exposure, and showed larger gains than the glass, carbon and basalt-only wraps reported in separate studies, although the hybrid used four layers against two for basalt-only and the studies are not directly comparable. These cylinder results come from one group; related jute–basalt work on RC beams gave flexural gains of about 40 percent [7]. In the sources we found, the hybrid wrap has not been tested on RC columns under cyclic loading or costed. Our preliminary cube test found a higher 3-day strength with loose jute and basalt strands (13.16 against 7.67 MPa), but it was one air-cured cube per group with unmeasured fibre content and is a prompt for further work, not a finding.

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