Tennessee TDOT Geotextile Fabrics

Solmax DOT Standard Specification Product Chart (click image to expand)

Tennessee TDOT - Geotextile Uses

Tennessee projects cross Mississippi River floodplains, red Piedmont-like clays, karstic limestone in Middle Tennessee, shale and sandstone in the Cumberland Plateau, and steep Appalachian corridors to the east. Add heavy rain, flash flooding, winter freeze–thaw in the mountains, and heavy truck volumes on I-40, I-24, I-75, and I-81, and you get subgrades that can soften, pump fines, rut, scour, or settle. Geotextiles are the quiet engineering layer that helps pavements, structures, and drainage systems keep performing through those stresses.

Separation and stabilization. On new lanes, shoulder widenings, and rehab work, TDOT commonly places a woven geotextile between native soil and granular base. The fabric keeps fine soils—expansive clays, silts, and weathered limestone fines—from migrating up into the aggregate under traffic, spreads load, and preserves base thickness. Where subgrades are very soft or saturated (floodplain approaches, utility cuts, low shoulders), crews first roll out geotextile to create a working platform so haul trucks and pavers don’t punch through. On exceptionally weak ground, geotextile is often paired with a geogrid for added stiffness and construction speed.

Filtration and drainage. Water drives many failures in Tennessee. Nonwoven geotextiles line underdrain and edge-drain trenches, wrap perforated pipe, and separate drainage stone from surrounding soils behind retaining walls and abutments. Selecting the right apparent opening size (AOS) and permittivity lets water move while fines stay put, reducing clogged outlets, wet spots, and shoulder drop-offs. In freeze–thaw zones, a nonwoven over open-graded aggregate can also create a capillary break, limiting upward moisture that weakens base layers in winter.

Riprap underlayment and scour control. Where flows concentrate—culverts, storm outfalls, river bends, and channel linings—geotextiles serve as underlayment beneath riprap or armor stone. A robust nonwoven filter is placed on the prepared bed or slope before rock. It prevents subgrade soils from piping through rock voids during high velocities, rapid drawdown, and debris-laden floods, helping the armor “lock in” and protecting embankments at bridge approaches along the Tennessee, Cumberland, and Holston systems.

Structures and MSE walls. TDOT corridors include many mechanically stabilized earth (MSE) walls and grade separations. Geotextiles act as joint and face filters, tucked behind panel or block joints so backfill fines don’t migrate to the face while drainage continuity is preserved. In karst areas, maintaining a continuous filter is especially important to prevent fines from migrating into voids and sinkholes.

Pavement interlayers. Asphalt-impregnated nonwoven geotextile beneath overlays improves waterproofing and slows reflective cracking—important where wide temperature swings, summer heat, and winter maintenance accelerate pavement aging. On chip seals common to preservation programs, paving fabrics limit water intrusion into base and subgrade, extending service life with minimal added thickness.

Temporary erosion and sediment control. During construction, geotextiles appear in silt fence, inlet protection, curb socks, and check structures. They filter runoff while trapping fines—critical for stormwater compliance on steep cuts in the Plateau and Appalachians and in urban work zones. At project entrances, stabilized construction exits typically include a nonwoven geotextile beneath coarse rock; the fabric distributes wheel loads and keeps stone from punching into wet soils, reducing track-out onto public roads.

Liner protection and containment. Heavy nonwoven geotextiles cushion geomembranes in stormwater basins, lined swales, salt-shed pads, and brine containment, protecting liners from puncture by angular aggregate and construction traffic.

Field practice. Performance hinges on basics: prepare subgrades smooth, avoid wrinkles, orient and overlap seams correctly (or sew where required), anchor with pins or the first lift, and cover promptly to limit UV exposure. Selection stays function-driven—woven for stabilization and tensile capacity; nonwoven for filtration, drainage, and protection—tuned to Tennessee’s soils, hydraulics, and traffic demands.

Bottom line: on TDOT projects, geotextile isn’t “landscape fabric.” It’s a purpose-chosen engineering layer that stabilizes soft ground, manages water and fines through storms and seasons, protects structures and channels, and stretches pavement life statewide.

Tennessee TDOT