Potential of oyster shell ash activated with cement as soil stabilizer for road construction

Abstract

The study investigated the suitability of oyster shell ash activated with cement as additive to improve soil geotechnical properties. Three Lateritic soil samples were collected and stabilized with varying percentages of oyster shell ash (OYSA) from 2%-15% activated with 5 % cement by dry weight. The mixtures’ geotechnical properties: Atterberg limit, specific gravity, California bearing ratio (CBR) and shear strength parameters (cohesion and angle of friction) were determined. Chemical analysis of the oyster shell ash was carried out in laboratory. Results showed that the OYSA is rich in calcium and silicon oxides (CaO and SiO 2 ) with other oxides. OYSA addition led to increase in specific gravity (2.42 to 2.43 sample 1; 2.24 to 2.50 sample 2 and 2.25-2.28 sample 3), improvement in Atterberg’s limit through decrease in the plasticity index, increase in the CBR (22.5%-145% sample 1, 0.54%-30.78% sample 2 and 1.56%-54.54% sample 3) and improvement of cohesive shear strength property (50-65kN/m 2 sample 1, 20-21 kN/m 2 sample 2, and 42 – 78 kN/m 2 sample 3)) due to the formation of cementitious layer and alteration in the structure and grain composition of soil samples. Therefore, using 6% OYSA activated with 5% cement will enhance soil geotechnical properties.