Effect of alkali treated sisal fibre on expansive clay

In this study, the synergic effects of alkaline activation (AA) and fibre inclusions, on the mechanical behaviour of fly ash stabilized black cotton soil was investigated. The natural fibre used in this research was treated with Sodium Hydroxide (NaOH) solution as an expedient solution to attain durability. The fibres are added in two forms: discrete fibres and geotextile. Assessment of engineering behaviour of the AA-treated soil reinforced with surface coated sisal fibres was carried out by conducting various laboratory tests like Free Swell (FS) test, Unconfined Compressive Strength (UCS) test, and cyclic triaxial test. Microstructural characterization was done by Scanning Electron Microscope (SEM) analysis and Fourier Transform Infra-Red (FTIR) spectroscopy analysis. The test results conclusively showed that the alkaline activated-fly ash treated-sisal fibre reinforced soil exhibits better mechanical behaviour in terms of peak stress and post-peak behaviour and appreciable resistance to swelling. Overall, the study shows that fibre-reinforced AA-fly ash amendment could effectively enhance the strength, stiffness and toughness of the soil and could subsidize the anticipated detrimental effects that could cause by dynamic loading. This study affirms the potential of alkali-treated sisal fibre as an alternative to traditional stabilizers for construction involving expansive soil.