Characterization of Lateralite: An Environment Friendly Chemical Additive for Soil Stabilization

Abstract

The objective of this paper is to determine the chemical composition of Lateralite stabilizer and to characterize Lateralite, stabilizer as a solution for improving the engineering properties of fined grained lateritic and clayey soil for road construction. Oxides and metallic compositions of Lateralite was determined by Atomic Absorption Spectroscopy, AAS, composition of chemical elements of Lateralite stabilizer was determined by X-ray Photoelectron Spectroscopy (XPS) and a quantitative analysis by Scanning Electron Microscopy (SEM) associated with Energy Dispersive X-ray spectroscopy (EDX). The oxide composition of Lateralite as determined by AAS is: Calcium Oxide (63.89%), Silicon Oxide (18.31%), Aluminium Oxide (5.89%), Ferrous oxide (1.67%), Magnesium oxide (1.56%), Sulphur oxide (1.22%), Potassium oxide (0.78%), Sodium oxide (0.41%) and L.O.I 6.27%.  The elemental composition analysis by XPS revealed ten (10) elements with Percentage Atomic Concentration, PAC, as: Oxygen (54.33%), Carbon (18.26%), Silicon (9.38%), Calcium (7.56%), Magnesium (4.08%), Aluminium (2.90%), Sodium (2.47%), Ferrous (0.44%), Sulphur (0.31%) and Nitrogen (0.27%) while SEM revealed eleven (11) elements: Oxygen (57.9%), Calcium (21.13%), Silicon (11.08%), Aluminium (4.23%), Ferrous (1.89%), Sulphur (1.07%), Magnesium (1.02%), Sodium (0.99%), Potassium (0.35%), Tin (0.18%) and Barium (0.17%). The three (3) characterization techniques used, (AAS, XPS and SEM) revealed the exchangeable cations in Lateralite are Calcium (7.56%), Magnesium (4.08%), Aluminium (2.90%) and Sodium (2.47%) which are in the ratio 3: 1.65:1.17:1, (Ca²⁺: Mg²⁺: Al³⁺ :Na⁺). This shows a high concentration and quantity of exchangeable calcium cations over other cations. This will enable the formation of Calcium compounds with very strong and stable inter-particle bonds and a stable Lateralite-stabilized soil mixture.