Virginia VDOT Geotextile Fabrics

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

Virginia VDOT - Geotextile Uses

Virginia projects sit on diverse ground: soft tidal marsh deposits and coastal sands in Hampton Roads, shrink–swell clays across the Piedmont, karstic limestones in the Valley and Ridge, and weathered rock in the mountains. Add hurricanes and nor’easters, flashier summer storms, winter freeze–thaw at elevation, heavy commuter loads in Northern Virginia, and the I-81 freight corridor, 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, crews place a woven geotextile between native soil and granular base. The fabric keeps fine soils—expansive clays, silts, and loose sands—from migrating up into the aggregate under traffic, spreads wheel loads, and preserves base thickness. Where subgrades are very soft or saturated (floodplain approaches, marsh edges, utility cuts), geotextile often goes down first as a working platform so trucks and pavers don’t punch through. On exceptionally weak or highly plastic soils, it’s commonly paired with a geogrid for added stiffness and construction speed.

Filtration and drainage. Water drives many failures in Virginia. Nonwoven geotextiles line underdrain and edge-drain trenches, wrap perforated pipe, and separate drainage stone from surrounding soils behind retaining walls and backwalls. Matching pore size (AOS) and permittivity to local soils—tight Piedmont clays vs. cleaner Coastal Plain sands—lets water move while fines stay put, reducing clogged outlets, wet spots, and shoulder drop-offs. In colder districts, a nonwoven over open-graded aggregate also forms a capillary break, limiting upward moisture that fuels frost heave and weakens base layers in winter.

Riprap underlayment and scour control. Where flows concentrate—culverts, storm outfalls, stream realignments, and tidal channels—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, wave run-up, and rapid drawdown, helping the armor “lock in” and protecting embankments at bridge approaches and channel bends along the James, Potomac, Rappahannock, and New River systems.

Structures and MSE walls. VDOT 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 maintaining drainage continuity. The same concept applies at wingwalls, backwalls, and around penetrations, where a filter layer preserves weeps without trapping water and prevents staining of facings.

Pavement interlayers. Asphalt-impregnated nonwoven geotextile beneath overlays improves waterproofing and slows reflective cracking—important where thermal swings, deicing chemicals, and heavy axle loads accelerate pavement aging. On chip seals used in preservation, paving fabrics limit water intrusion into base and subgrade 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 from the mountains to the Bay. At site entrances, stabilized construction exits typically include a nonwoven geotextile beneath coarse stone; the fabric distributes wheel loads and prevents rock 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 brine containment, protecting liners from puncture by angular aggregate and construction traffic.

Field practice that makes it work. Prepare subgrades smooth, remove protrusions, and avoid wrinkles; orient rolls correctly; lap or sew seams as specified (more overlap on very soft ground); anchor with pins or the first lift; and cover promptly to limit UV and heat exposure. Selection stays function-driven—woven for stabilization and tensile capacity; nonwoven for filtration, drainage, and protection—tuned to Virginia’s soils, hydraulics, and traffic demands.

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

Virginia VDOT