South Carolina SCDOT Geotextile Fabrics

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

South Carolina SCDOT - Geotextile Uses

South Carolina projects span loose Coastal Plain sands and tidal marsh deposits in the Lowcountry, red Piedmont clays through the Midlands, and steep Blue Ridge foothills upstate. Add hurricanes, tropical downpours, high water tables, and heavy freight on I-95, I-26, and I-20, and you get subgrades that can rut, pump, scour, or lose fines. Geotextiles are the quiet engineering layer that helps pavements, structures, and drainage systems perform in these conditions.

Separation and stabilization. On new lanes, shoulder widenings, and rehab jobs, crews place a woven geotextile between native soil and granular base. The fabric keeps fine soils—plastic clays in the Piedmont and silty or organic Lowcountry soils—from migrating into the aggregate under traffic, spreads wheel loads, and preserves base thickness. Where subgrades are very soft or saturated (marsh edges, floodplain approaches, utility cuts), geotextile often serves first as a working platform so trucks and pavers don’t punch through. On exceptionally weak or variable ground, it’s commonly paired with a geogrid to add stiffness and speed construction.

Filtration and drainage. Water management is paramount in a hurricane- and thunderstorm-prone state. Nonwoven geotextiles line underdrain trenches, wrap perforated pipe, and separate drainage stone from surrounding soils behind retaining walls and abutments. Matching apparent opening size (AOS) and permittivity to local soils—clean sands near the coast versus tighter silts and clays inland—lets water move freely while fines stay put, reducing clogged outlets, wet shoulders, and base softening after big rain events. In cooler upstate corridors, a nonwoven over open-graded aggregate can also serve as a capillary break, limiting upward moisture during cold snaps.

Riprap underlayment and coastal scour. Where flows concentrate—culverts, storm outfalls, tidal creeks, and riverbanks—geotextiles act as underlayment beneath riprap or armor stone. A robust nonwoven filter goes on the prepared bed or slope before rock placement. It prevents subgrade soils from piping through rock voids during high velocities, wave run-up, and drawdown, helping the armor “lock in” and protecting embankments at bridge approaches, causeways, and estuarine shorelines.

Structures and MSE walls. SCDOT corridors include extensive mechanically stabilized earth (MSE) walls and grade separations. Geotextiles serve as joint and face filters, tucked behind panel or block joints to keep backfill fines from migrating to the face while maintaining drainage continuity. The same concept applies around structural penetrations, wingwalls, and backwalls, preserving weeps and outlets without trapping water.

Pavement interlayers. Asphalt-impregnated nonwoven geotextile beneath overlays improves waterproofing and slows reflective cracking—important where heat, heavy axle loads, and frequent wetting accelerate pavement aging. On preservation chip seals common to secondary routes, 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—crucial for stormwater compliance in coastal watersheds and urban work zones. At project entrances, stabilized construction exits typically include a nonwoven geotextile beneath coarse rock; the fabric distributes wheel loads and prevents the stone from punching into wet soils, reducing track-out.

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

Field practice. Performance hinges on basics: prepare subgrades smooth, avoid wrinkles, use proper overlaps or sewn seams, anchor with pins or the first lift, and cover promptly to limit intense UV and heat. Selection is function-driven—woven for stabilization and tensile capacity; nonwoven for filtration, drainage, and protection—tuned to South Carolina’s soils, hydraulics, and traffic demands.



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

South Carolina SCDOT