Evaluating the Unconfined Compressive Strength Retention of Corn Starch Stabilized Lateritic Soils
Bright, Worlu
Centre for Geotechnical and Coastal Engineering Research, CGCER, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria.
Eme, Dennis Budu
Department of Civil Engineering, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria.
Ohwerhi Kelly Erhiferhi
*
Department of Civil Engineering, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This study evaluates the effectiveness of corn starch as a sustainable stabilizer for lateritic soils, focusing on unconfined compressive strength (UCS) retention under wet–dry cycles. A (3,2) Scheffé simplex lattice design was employed to vary lateritic soil, corn starch, and water-to-solids (w/s) ratio across 12 mixes (6 trial, 6 control). Samples were cured for 28 days, then subjected to 12 wet–dry cycles to assess UCS retention. UCS retention ranged from 69.68% to 90.12% for trial mixes and 69.68% to 91.24% for control mixes, indicating strong durability. The best-performing mixes exceeded 90%, confirming corn starch’s potential for long-term stabilization. The Scheffé regression model developed had an R² of 0.998 and an F-value of 1.056 (< F-critical of 5.05), confirming predictive reliability and statistical adequacy. Model coefficients showed corn starch had the greatest influence (β₂ = 87.50), followed by lateritic soil (β₁ = 83.33) and water-to-solids ratio (β₃ = 69.68). Positive interactions between lateritic soil and corn starch (18.82) and between lateritic soil and water-to-solids ratio (43.98) improved retention, while a slight negative effect between corn starch and water-to-solids ratio (−0.72) indicated that excess water could reduce binding. Overall, corn starch significantly improves UCS retention, offering a durable, eco-friendly solution for lateritic soil stabilization.
Keywords: Unconfined compressive strength retention, durability, lateritic soil, corn starch, Scheffe’s regression, simplex lattic design