Innovative Use of Sawdust Waste for Soil Stabilization: A Sustainable Approach in Geotechnical Engineering

Abstract

The need for low-carbon alternatives to traditional soil-stabilizing methods, including cement and lime, has grown in response to rising urbanization and the desire for more environmentally friendly infrastructure. Many studies have focused on sawdust ash or blended systems, but the behaviour of raw sawdust in clay soils, particularly under tropical conditions, has not been thoroughly investigated. This is although lignocellulosic waste materials, and sawdust in particular, offer a potentially environmentally friendly solution. Therefore, this study aims to investigate the effect of raw sawdust on the consistency limits and compaction characteristics of clay soil and to evaluate its potential as a sustainable soil stabilizer. Laboratory experiments were conducted using Atterberg Limits and Standard Proctor Compaction Tests on untreated soil (control) and soil treated with 5% sawdust by dry weight. The result shows that the plasticity index increased from 38.52% to 54.41%, indicating higher moisture sensitivity, while increases in liquid and plastic limits suggest reduced structural stability. Compaction results reveal a decrease in maximum dry density from 1.36 g/cm³ at 15.56% moisture content to 1.15 g/cm³ at 23.08%, reflecting the lightweight and hygroscopic nature of sawdust. Overall, while sawdust contributes to waste reduction and supports circular economy practices, it reduces soil strength and compaction efficiency, making it more suitable for non-load-bearing or lightly loaded applications, or when used in combination with stabilizing agents. This study provides important insights into the potential and limitations of raw sawdust for sustainable ground improvement.