Volume 2, Issue 3, January - June, 2025

Geotechnical characteristics of soils stabilized with lime-Rice Husk Ash for road construction in Nigeria Southwestern states

Faluyi Sunday Olubunmi^1♦, Amu Olugbenga Oludolapo², Adekanmi Jonathan Segun¹

¹Department of Civil Engineering, The Federal Polytechnic, Ado- Ekiti, Nigeria
²Department of Civil Engineering, Federal University Oye-Ekiti, Nigeria

^♦Corresponding Author
Department of Civil Engineering, The Federal Polytechnic, Ado- Ekiti, Nigeria

ABSTRACT

The state of roads in southwestern Nigeria is deplorable. Most of them are not motorable due to pavement failure; this necessitates an investigation into determining the suitability of the underlying soil courses if stabilized with lime-Rice Husk Ash (RHA) mixtures. This investigation used eighteen (18) selected burrow pit soil samples (one from each senatorial district of Southwestern, Nigeria) which are used for road construction. California Bearing Ratio (CBR), compaction, Unconfined Compressive Strength (UCS), and triaxial tests were performed on 6% lime and 0 to 10% RHA mixed soil samples in the laboratory using standard procedures. The additive was also subjected to laboratory test for chemical analysis. The results showed that RHA additive has high silica (Sio2) content and that all strength properties Maximum Dry Density (MDD), CBR, UCS, Cohesion (C), Shear Strength (τ), and angle of internal frictional (ø) increase as RHA content increases and reached the optimum at 4% RHA content, then decrease afterward. The Optimum Moisture Content (OMC) decreases with corresponding increase in RHA content. Almost all of the unsuitable soil samples became suitable for pavement layer materials after stabilization. The mixture of 6% optimum lime and 4% RHA content is recommended for soil improvement, particularly for road construction in Southwestern Nigeria.

Keywords: Rice Husk Ash, Chemical analysis, Lime, Strength properties, Stabilization

Discovery Nature, 2025, 2(3), e5dn1051

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DOI: https://doi.org/10.54905/disssi.v2i3.e5dn1051

Published: 18 February 2025