Missouri MODOT Geotextile Fabrics

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

Missouri MODOT - Geotextile Uses

Missouri projects span claypan soils across the north, thick loess along river bluffs, alluvial sands and silts in the Mississippi River Bootheel, and karstic limestone terrain in the Ozarks. Add freeze–thaw cycles, intense spring and summer thunderstorms, flooding on the Missouri and Mississippi Rivers, and heavy truck traffic on corridors like I-70 and I-44, 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 rehabilitation work, a woven geotextile is placed between native soil and granular base. It prevents fine soils—especially plastic clays and loess—from migrating upward into the aggregate under traffic, spreads load, and preserves base thickness. Where subgrades are very soft or saturated (floodplain approaches, utility crossings, low shoulders), geotextile creates a working platform so haul trucks and pavers don’t punch through. On exceptionally weak ground, the fabric is often paired with a geogrid to boost stiffness and construction speed.

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

Riprap underlayment and scour control. Where flows concentrate—culverts, storm outfalls, streambanks, and channel linings—geotextiles serve as underlayment beneath riprap or rock armor. A tough nonwoven filter goes on the prepared slope or bed before stone placement. It prevents the subgrade from piping through rock voids during high velocities, drawdown, and debris-laden floods, helping the riprap “lock in” and protecting embankments at bridge approaches and channel bends from the Ozark streams to the Mississippi bottoms.

Structures and MSE walls. MoDOT 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. The same idea applies at wingwalls, backwalls, and structural penetrations, where a filter layer keeps weeps functioning without trapping water. 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—useful where thermal swings, heavy axle loads, and deicing salts accelerate pavement aging. On chip seals used widely on rural routes, paving fabrics limit water intrusion into base and subgrade, extending service life with minimal added thickness.

Temporary erosion and sediment control. Geotextiles appear in silt fence, inlet protection, curb socks, and ditch checks. They filter runoff while trapping fines—critical for stormwater compliance on long medians, steep 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 soils, reducing track-out.

Liner protection and containment. Heavy nonwoven geotextiles cushion geomembranes in stormwater basins, lined ditches, salt-shed pads, and brine containment areas, 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 UV exposure. Selection is function-driven—woven for stabilization and tensile capacity; nonwoven for filtration, drainage, and protection—tuned to Missouri’s soils, hydraulics, and traffic demands.

Bottom line: on MoDOT projects, geotextile isn’t “landscape fabric.” It’s a purpose-chosen engineering layer that stabilizes soft ground, controls water and fines through floods and freeze–thaw, protects structures and channels, and stretches pavement life statewide.

Missouri MODOT