South Dakota SDDOT Geotextile Fabrics

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

South Dakota SDDOT - Geotextile Uses

South Dakota projects span glacial tills and lakebed clays in the east, windblown loess, Pierre Shale and rolling prairie in the central counties, and granitic and sedimentary terrains in the Black Hills. Add deep freeze–thaw cycles, blizzards, spring snowmelt, ice-out events, localized cloudbursts, and heavy ag and freight traffic on I-90 and I-29, and you get subgrades that can soften, pump fines, rut, scour, and settle. Geotextiles are the quiet engineering layer that helps pavements, structures, and drainage systems keep performing.

Separation and stabilization. On new lanes, shoulder widenings, and rehab work, SDDOT commonly places a woven geotextile between native soil and granular base. The fabric blocks fine silts and clays—especially from glacial tills and weathered shale—from migrating into the aggregate under traffic, spreads wheel loads, and preserves base thickness. Where subgrades are very soft or saturated (floodplain approaches, pothole-prone low spots, utility cuts), crews roll out geotextile first to create a working platform so haul trucks and pavers don’t punch through. On exceptionally weak ground, it’s often paired with a geogrid to add stiffness and speed construction.

Filtration and drainage. Water drives many failures on the Plains. Nonwoven geotextiles line underdrain and edge-drain trenches, wrap perforated pipe, and separate drainage stone from surrounding soils behind retaining walls and backwalls. Selecting the right apparent opening size (AOS) and permittivity lets water move while fines stay put, reducing clogged outlets, shoulder drop-offs, and wet spots that shorten pavement life. In cold regions, a nonwoven atop open-graded aggregate also forms a capillary break, limiting upward moisture that fuels frost heave and weakens base layers during long winters.

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 tough 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, ice breakup, and debris-laden floods, helping the armor “lock in” and protecting embankments at bridge approaches and channel transitions along the Missouri, James, and Big Sioux systems.

Structures and MSE walls. SDDOT corridors include many mechanically stabilized earth (MSE) walls and grade separations. Geotextiles act as joint and face filters, tucked behind precast panels or modular block joints so backfill fines don’t migrate to the face while drainage continuity is preserved. The same concept applies at wingwalls, backwalls, and around penetrations, where a filter layer keeps weeps functioning without trapping water.

Pavement interlayers. Asphalt-impregnated nonwoven geotextile beneath overlays improves waterproofing and slows reflective cracking—important where thermal swings, studded tire use in some areas, and deicing chemicals accelerate pavement aging. On chip seals common to rural 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—critical for stormwater compliance on long medians, steep approach cuts, and urban work zones. At project entrances, stabilized construction exits typically include a nonwoven geotextile beneath coarse rock; the fabric spreads wheel loads and prevents stone from punching into wet or thaw-weakened soils, reducing track-out.

Liner protection and containment. Heavy nonwoven geotextiles cushion geomembranes in stormwater basins, lined ditches, salt- and sand-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, overlap or sew seams as required, anchor with pins or the first lift, and cover promptly to limit harsh UV and winter weathering. Selection is function-driven—woven for stabilization and tensile capacity; nonwoven for filtration, drainage, and protection—tuned to South Dakota’s soils, hydraulics, and traffic demands.

South Dakota SDDOT