Statewide Survey of Chemically Stabilized Soil Properties for Mechanistic-Empirical Pavement Design

Over 450 cores were extracted from roadways throughout Mississippi to provide a realistic picture of mechanical properties in later-age chemically stabilized soil. Cores ranged from 10 to 54 years old and were stabilized with either lime-fly ash, cement, or lime. Indirect tensile strength (IDT), unconfined compressive strength (UCS), and elastic modulus (E) tests were used to quantify mechanical properties. Generally speaking, IDT, UCS, and E values tended not to exceed 250, 1500, and 1,500,000 psi (1724 kPa, 10,342 kPa, and 10,342 MPa), respectively, in pavements over 10 years old. Cores were also compared to mechanical property relationships found in the 1993 AASHTO design guide and the Mechanistic-Empirical Pavement Design Guide (MEPDG) and the literature to determine their applicability to later-age pavement properties. Relationships from the literature comparing IDT to UCS were generally good predictors of later-age property relationships; however, relationships between E and UCS were not good predictors of later-age strength as most equations did not account for the decrease in E development over time when compared to UCS.