Effect of Sand Addition on Laterite Soil Stabilization

Area of Science:

• Geotechnical Engineering
• Materials Science

Background:

• Lateritic soils are abundant in tropical regions and have a history of use in flexible pavement unbound layers in Brazil.
• Traditional methods often discard lateritic soils or require stabilization based on limited parameters like gradation and Atterberg limits.

Purpose of the Study:

• To investigate the mechanical characteristics of a Roraima lateritic soil, focusing on resilient modulus and permanent deformation.
• To evaluate the effect of adding 20% sand on the lateritic soil's mechanical behavior for pavement applications.

Main Methods:

• Repeated load triaxial tests were conducted to assess mechanical properties.
• Shakedown analysis was performed to evaluate material stability under repeated loading.

Main Results:

• The laterite-sand mixture (744 MPa) showed a lower average resilient modulus (RM) than pure lateritic soil (790 MPa).
• The mixture with sand experienced nearly double the plastic strain compared to pure laterite.
• Pure laterite exhibited more stable performance in shakedown analysis, indicating greater durability.

Conclusions:

• Sand addition did not significantly enhance the mechanical performance of the lateritic soil for pavement applications.
• Pure lateritic soil is a viable material for pavement construction, offering superior strength and durability compared to the sand mixture.
• Findings underscore the need for advanced mechanical testing beyond conventional methods for lateritic soils.