Memphis sits on a complex foundation of Mississippi River alluvium and loess deposits that create unique challenges for pavement engineers. The subsurface across Shelby County typically consists of 15 to 30 feet of silty clay and sandy silt overlying the Jackson Formation, with groundwater often perched within the upper 10 feet during wet seasons. Designing flexible pavement here means confronting expansive soils, variable moisture regimes, and the freeze-thaw cycles that degrade underbuilt road sections within three to five years. Our team approaches every flexible pavement design by first characterizing the subgrade through a targeted field investigation — because the AASHTO 93 empirical method demands accurate resilient modulus values, not assumed ones. For projects near the Wolf River floodway or industrial corridors south of downtown, we often combine pavement design with CBR road testing to calibrate structural numbers against site-specific bearing capacity, ensuring the asphalt concrete and aggregate base layers perform across Memphis's seasonal extremes.
A flexible pavement section is only as reliable as the subgrade characterization beneath it — skip the resilient modulus testing in Memphis clay and you are designing blind.
