An Experimental Investigation and Numerical Modeling of Glass Fiber-Reinforced Expansive Subgrade Soil With Alkaline Stabilizer

Untreated expansive subgrade soil attains weak geomechanical stability against periodic moisture fluctuation, leading to massive damage on pavement structures. Traditional binders degrade the atmosphere by producing greenhouse gases. This study examines the geoengineering effectiveness of glass fiber composite alkaline binder mixed soil (GF-AS) with different fly ash-sugarcane bagasse ash (SBA) percentages. Alkaline stabilizer (AS) is formed by reacting an alkali solution (NaOH + Na2SiO3) with industrial residual pozzolanic precursors (sugarcane bagasse + fly ash) at 0.4 water-to-solids ratios. The effects of fiber, SBA, and binder doses on the penetration resistance and indirect tensile strength (ITS) in fiber-reinforced soil are quite significant. Mineralogical and morphological studies using powder X-ray crystallography and field emission scanning electron micrographs are conducted to understand the micro surface texture between soil-fiber mixture. The alkaline-fiber soil exhibits higher interfacial bonding and interlocking density compared to lime-fiber soil. A finite element analysis carried out in commercially available software to assess the strength performance of soil with varying binder content in subgrade applications shows that the alkaline-treated subgrade soil exhibits less deformation compared to the lime-treated soil.