GEOTECHNICAL CHARACTERIZATION AND STABILIZATION PERFORMANCE OF LATERITIC SOIL TREATED WITH CASSAVA PEEL ASH AND LIME

Abstract

This study evaluated the geotechnical characterization and stabilization performance of lateritic
soils treated with cassava peel ash (CPA) and lime for pavement applications. Lateritic soil
samples obtained from selected locations within the three senatorial districts of Kwara State,
Nigeria, were subjected to laboratory tests including natural moisture content, specific gravity,
particle size distribution, and Atterberg limits to determine their natural engineering properties.
Chemical composition analysis was conducted to assess the pozzolanic potential of the cassava
peel ash. Representative soil samples were subsequently stabilized using varying proportions of
CPA–lime blends and tested for consistency characteristics, compaction behavior, and California
Bearing Ratio (CBR). The natural soils were predominantly classified as A-7-5 materials under
the American Association of State Highway and Transportation Officials classification system,
indicating poor subgrade suitability in their untreated condition. The results revealed that
stabilization with CPA and lime significantly reduced soil plasticity while improving compaction
and bearing capacity characteristics. The optimum engineering performance was achieved at a
blend ratio of 75% lime and 25% CPA. The study concluded that cassava peel ash–lime
stabilization is an effective and sustainable approach for enhancing the engineering properties of
lateritic soils for road pavement construction.