Investigating the Use of Hydrated Lime and Rice Husk Ash in the Stabilization of Silty Clay Soils. Case Study: Nakivubo Primary School in Kampala
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Date
2024-04-17
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Abstract
This study examines the engineering properties of silty clay soils and their
improvement through stabilization with hydrated lime and rice husk ash (RHA).
Initial findings show untreated silty clay has poor load-bearing capacity and
high plasticity, unsuitable for subgrade applications. Chemical analysis
confirms RHA meets ASTM C 618-2012 standards, with SiO2 + Fe2O3 + Al2O3
content exceeding 70%. Optimal stabilization with 4% lime and 8% RHA
enhances soil properties: reducing plasticity index, increasing CBR from 8% to
35%, and surpassing UCS requirement (0.5 MPa). Lime-RHA treatment yields a
Compression Index (Cc) of 0.23 and Recompression Index (Cr) of 0.06,
improving load-bearing capacity. Soil shows suitability for stabilization with
low free swell index (2.3%), negligible moisture, slightly alkaline pH,
moderate density (1.52), and low electrical conductivity. Further RHA
addition (12%) decreases CBR and UCS, emphasizing stabilizer balance. In
conclusion, combined lime-RHA application offers a promising method for
subgrade construction, enhancing soil strength, reducing water sensitivity,
and potentially improving drainage.