Modification of a Lateritic Soil with Lime and Cement: An Economical Alternative for Flexible Pavement Layers

Lateritic soils are widely spread in the Brazilian territory and they have been used as subgrade of pavement layers. Specifically, the Red-yellow latosols are usually clayey soils and are characterized as low bearing capacity materials for flexible pavement layers. As a conventional solution, soil stabilization with hydrated lime or Portland cement has been used as pavement layers reinforcement. However, the addition of low contents of stabilizers, referring to the soil modification, has not been applied on regular basis in highway designs. The purpose of this paper is to evaluate the use of low contents of lime and cement in the modification of a lateritic soil properties concerning the behavior of mixtures since of the beginning of construction to the resulting final product. At this point, the workability, chemical properties, mechanical behavior and mineralogical composition were evaluated. Mechanistic analyses were performed in order to verify fatigue failures on asphalt layers in roadways structural layers. Experimental results showed that addition of 2% and 3% of lime or cement was enough to change the soil workability and mechanical strength. Additionally, mechanistic analyses supported the soil modification technique as valuable practice with low elastic strains in the asphalt layer when applied in pavement base layers.