Efficacy of Almond Shell Ash Inclusion on the Geotechnical Behavior of Lime Blended Kaolinitic Soil

Abstract

The current study focuses on studying the effect of almond shell ash (ASA) inclusion along with lime in addressing issues related to strength and volume change behavior of a typical problematic soil. Experiments were carried out on both natural as well as amended soil mixtures having varying percentages of lime and ASA (added based on dry weight of soil). The addition of ASA reduced the plasticity characteristics of selected kaolinite rich clay. Of all the mixtures, the mixture containing 1% ASA and 0.5% lime exhibited maximum optimum moisture content (OMC) and lowest value of maximum dry density (MDD). Upon curing to 28 days, the same mixture exhibited the unconfined compression strength (UCS) value 76 kN/m2. The results pertaining to UCS values indicated that the rate of gain of strength increased proportionally up to 1% ASA addition, followed by which there was a consistent decrease in the rate of gain of strength even in the presence of lime and is attributed to pore saturation with ASA. The addition of lime aids in better binding between non-plastic ASA particles and kaolinite-rich clay which was confirmed by scanning electron microscopic (SEM) images and X-ray diffraction (XRD) studies. SEM images confirmed the presence of agglomerated particles with homogenous mass exhibiting reduced pore opening size for mixture containing both ASA and lime.