Incorporating Chemical Stabilization of the Subgrade in Pavement Design andConstruction Practices

Roadbeds are considered one of the most problematic components in pavement design and construction. Its engineering properties differ significantly in terms of soil composition, gradation, and strength parameters. Soil stabilization techniques have been widely used to improve the engineering properties of roadbed soils. Therefore, in order to study the effects of the stabilization of subgrade layers for pavement structures, theoretical and experimental work was carried out to study pavement responses constructed over stabilized subgrade with lime and cement. The theoretical study involved creating finite element models to study the nature of stresses and strains in the subgrade and asphalt layers when stabilized layer is used in the pavement structure. To study the durability and long term performance of chemically stabilized subgrade, FWD and DCP tests were performed on several pavement sections constructed with stabilized layer. The results from the theoretical study showed that the subgrade could be protected from being over-stressed during construction by providing a suitable stabilized layer. Results from field testing showed that the stiffness of chemically stabilized layers increases significantly over time. It also showed that it provides structural stability to the pavement constructed over stabilized subgrades. Based on these results, input parameters were recommended to MEPDG of flexible pavements.