Enhancing soft subgrade performance with geocomposite-embedded capping layer: utilising Australian granular pavement design chart for assessing geocomposite benefits

Abstract

Improving soft subgrades in road construction is essential for efficient machinery use, reducing gravel layer thickness, and enhancing pavement performance. Traditional methods like gravel replacement and chemical stabilisation are costly and harmful to the environment. Geosynthetics offer a cost-effective, eco-friendly alternative, but their full potential in Australian pavement design remains untapped due to limited research on estimating their modulus. This study addresses this gap by modeling geosynthetic-stabilised subgrades in a controlled environment and conducting plate load tests. Results show that incorporating geocomposites reduces capping layer thickness by 25% and overall granular cover by 20%. By developing a method to estimate geosynthetic-stabilised subgrade modulus and integrating it into design charts, this research aims to promote more efficient and sustainable road construction practices in Australia.