Effect of Fly Ash and Synthetic Fibers on the Desiccation Cracking of Expansive Clay

Expansive clays are abundant in many strategically important places in India. They undergo volumetric changes by swelling and shrinkage upon seasonal moisture variations. The hysteresis of swelling and shrinkage leads to desiccation cracking, loss of shear strength, change in consolidation characteristics, increase in permeability, and seepage characteristics. Generally, these soils are replaced with a more desirable material for construction. This study aims at sustainable use of expansive clay from Surat in barrier systems as the clay possesses permeability of the desirable range of 1 × 10–9 m/s. Expansive clay was mixed with fly ash and reinforced with discrete and randomly distributed polypropylene fibers of length 12 mm and varying fiber contents. The tensile strength behavior of fiber-reinforced expansive clay was studied by performing desiccation cracking and direct tensile strength tests. The desiccation cracking tests were performed under controlled environmental conditions. The results indicate 89.9% of crack reduction due to the presence of reinforcing fibers and fly ash. The bridging action of fibers increases the tensile strength of clay and prevents cracking of expansive clay, thereby maintaining the integrity of the clay layer.